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Fundamental Studies on Moisture Sorption Behavior of Textiles
一 Moistyre Absorption and Desorption Isotherms
of CbMulosic Fibers 一
A Dissertation Presented by
l〈AZUNORI KOHATA
to
Department of Practical Life Studies
Faculty of Teacher Education
Hyogo University ot’ Teacher Education
Hyogo 673－14， Japan
1984
．Fundamental Studies on Moisture Sorption B．ehavior of Textiles
一 Moisture Absorption arid Desorption lsotherms of Cellulos．ic ’Fibers 一一
by Kazungri KOHATA
ContentS
Abstruc’煤D
Chapte’秩@1．
Chapter 2．
Chapter 3．
Ch．apter 4．
Chapter 5．
Chapter 6．
Introduction．
Brief SurVey on the Theories of Sorption lsotherms
of Textile Fibers．
2－1． Brunaue．r， Emmett and Teller i s，Theory of
Adsorption 工sotherm．
2－2． Thermodynainic Approach to Adsorption lsotherm
by Hill．
Apparatus Constructed for Measuri．ng the Sorption
Isotherm．
prbparation and characterization of Test specimens．
Experimental Results and Discussion．
f5－1’． Thermodynamics of Moisture Absorption．
’5－2． Ab＄orption and Pesorption Hysteresis．
5・一3．． Analyses of APsorption lsotherms． of Cellulosic
Fibers in Terms of Theories of BET Multilayer
Adsorption and of Hill’s Thermodynamic Approach．
5－4． Structural Characterization of Adsorbed Water by
Means Qf Differential Scanning Calorimetry．
Conclusion．
1
2
14
15
21
Qノ つ」 【」［」◎ノ3
り」 4 β◎戸◎．671
80
128
一1一
Abstract
Twel ve kind’s of cell．ulosic ．fiber ， including’natural，．negenerated， and ，．
1四割老，鼎賑賑．ll謙。ぎe鼎㍊：dll締。稀題n乳甜r1巴ol邑t16rllb13「p・．
means of two ，types 一〇f gravimetric methods 1－a weighing bottle method and 一a－
sorption balance method wi，th quartz spring in vacuum．
From the temperature depen’dence of the’ sorption isotherms， the exess
energy of moisture absorption on to the cellulose fibers was found to belargest in dry state， rahgin．g up to a．values at least，．mo’r．e th．an． 100 cal／gr’
of l iquid water， and to decrease down to almost zero’with increasing relativehumidity up to saturation． These results suggest that the adsorbed waterswere very firmly bound in the dry state to the adsorbent in an extent toform the crystal lattice of ice， whereas the waters were loosely absorbedin the saturated state to form bulk water．
The sorption isotherms at a given temperature of 30 OC were analyzed
in terms of the Brunauer， Emmett and TeHer’s （BET） multilayer adsorption
l舗翻舗鵬，lh麗lll、ll，ll丁直s constants・v・・。・and nmax・The
1濃ldnmax・。li9魏u理dl臨。lf，温lelhlaざ隻1翻。譜d。寵「Σ1継ら1－
mediate range of relative hutnidities， was found to be 6 for almost everycellulosic fibers with exceptions of 7 for Na－carboxymethylated rayonand of 4 for tri－acetate raYon．
記。掬1留二ef翻’ll臨t；。認，聖maXまん＞a謙1もt，991。鴇1詰t’Ve
volumd ”oi m6n61ayer’adgo“bth‘ofi－6F’watbF per gr “of 6ry mateVial， for
most of cellulosic fibers with－except．i．ons of di一・and．tri－acetate rayonsi
諮一v哩1階lltlyt織1鍛麟二認ll牒。m艦lll臨1cell’浮撃盾唐пffibers’
C一’
Und acdtatbJfib’ brs in’the brdeif’pf・des’Cendin－g wqteyi’
accessibility， possibly reflecting the differences’ 奄氏@chemical andphysical structures of noncrystalline region of the materials．
4） When plotting the moisture regains with n ＝ 1 （Langmuir’s monolayer
皐1羅’鋸1論1諜i器囎1瀦諮nll，tll。ll囎牌．vm’、離in the water accessfibility； i．e．， the slope in the vicinity for acetate
rayons being about one－third to that in the vicinity for regenerated
rayons．
5） When poltting the value’s of C， bonding energy characteristics between
adsorbent and water molecules， against the nqmber of hydroxyl groups per cellobi， ose u，nil ， there found roughly a l inear relation． But plotting the
vm， there hardly found any quantitative values of C against the normalized corr6tation， 5ut 5ust a tendencSf thaT“the larger tVhe value oUf c’， the
normal ized vm becomes larger．
Finally， the nature of adsorbed water was examined by comparing themoisture regains．of different n with those by a current micrQ－calorimetricinvestigations， deduciRg a conclusion that the adsorbed waters with n aslarge as 7 to 8 are still calssified as ’freezable bound－water’ and thosewith n less than 6 are as ’nonfreezable bound－water’．
一一 2－
Chapter 1． lntroduction
The interactions of moisture and fibers．haye many t．echnigal consegur．．
ences： t Dhe weight changes are of direct financjal importance， and they may
also influence the composition of a blend or the aPparent count of a yarn．
Because of the aSsociated heat effe’cts， conditiohing is a slow process， and
textiles buffer changes of temperature which the body woyld otherwise
experience． Swellfing’ results in dimensional changes of yearns and fabrics 一
sometimes this is advantageous， as in the closing of pores of Ventile
fabrics， but more often it is a nuisance，’causing garments to become ill－
fitting． The changes in mechan’ical properties， such as the increased stren－
gth of wet cotton and the l ower strength of wet rayon， influence the behavior
of textiles under different atmospheric conditions． The amount of water
・b…b・dby fibers va，i，、 c。n、id，，、bly．1， generaいh。、e ’Bhう、h、b，。．b
…t・・ter a・e ea・i・・t・d・yr・・re p・・ne t・micr・br・1・grcal・ttacいess
prone to static electrification， and better conductors of electricity．
Af「b・・us m・t・・「・1・xp。・ed t・uゆangi・g external…d「t「・・s att・『・・
ultimately a moisture content that remains constant so long as these condi－
t’
奄盾獅刀@remain unaltered． This constancy of moisture content is not a static
state but is the result of a dynamic equilibrium， in which the amount of
water evaporating from the fibers，in unit time is extactly counterba］enced’
by that condensing on them． The rate of evaporation depends on the amount
of water a3ready taken up and on temperature， wh“e the rate of condensation
depends on’@the number of potential absorbing points in the fibers that
are sti11 unoccupied and on the concentration of water vapour in the sur－
rounding atmosphere． Hence， the fundamental v．ariables controlling the amount
of water in the material are the constitution and structure of the fiber
itself， the temperature and concentration of water in the fiber surroundings；
mpte sorption i sotherm． i s the curve that expresses the relation， at any
一 3 一一
constant temperature， between the amount of water in the fiber and i・ts
concentration outsiqe， and is one of the most fundamentals to investigate
the interactions of moisture and fibers． The amount of water in the fiber
is generally expressed as a fraction or percentage of the weight of dry
fiber， when it is called ’moisture regain’， though occasi．ona，］ly it is
referred to ’しhe combined weight of fiber and water， when it js ca］led
’moisture content’； 一th’?@concentration of water in the surrounding atmosphere
is expressed as the relative vapour pressure （．the partial pressure of
water vapour divided by the saturation vapour pressure at the temperature
concemed）・oゆy 109 times th・t value・c・mm・・1y k・・wn as塵％・e1・tive
h、mrd甫tゾ：
There have been two groups of direct methods of determining the sorption
isotherm． ln the first， the sample is maintafined at given water vapour pre一一
ssure in an encl．osed space and the changes in its mass are measured． A simple
method of doing this with samples in weighing bottles has ’ b??氏@described
1）
by Bu11， water vapour at known pressures being provided by mixtures of
sulphuric acid and water in varying proportions． Other modifications of
thi、 m，th。d have been、sed by個1。n et、1．2）and by U，q、h、，t and Wmi、m、．3）
If the，appratug i’s evacuated， the approach to equilibriurn is speeded up．4）
Contfinuou，s observation of the changes fin weight of the sample may be made
by hanging fit on a quartz or tungsten spi’ral spring， as described by McBain5’6）
and by others．7’8） Ashpole has described a way of making these experiments
・F high h・mid帽…9）・h・・e th…i・ ・ ・i・k・f・uper・aturatう・・if th・t・m－
perature is not very closely controlled， and the approach to equilibrium
is’slow．
The basic apparatus for the second group of methodg consists of a bulb
containing ．the fiber which is connected to a mercury manometer， or some other
device fo．r measur’ing vapour pressure， and through a tap to reservoir of
一4－
water． After the fibers and the space around them are dried under a high
vacuurn， a known mass of water is admfitted， and the vapour pressure－is
measured after equVibrium has been reached． Thus， the total mass of water
present within and around the fibers is kept constant durfing a test． This
is repeated for successivd additions of water． This method yfie’ 撃р刀@more
accurate results than the first met－hod， especially fin the difficult condi－
tions at very low and very high humidities， though it has been criticized
on the ground that the vapour pressure is changing during the approach to
10）
Details of the method have been described by Urquhart andequilibrium．
湘1r、m、，ll）and．ece，tly T，yl。，1 2・13）h、、 d，、crib，d、m。re ，1、b。，at。
arrangement specially for use below 4％ relative humidity．
Sorption iso’しherms have be6n determine（l for many different systems
including text“e fibers， and five types of the isotherm have been noted；
these are shown schematicaHy in Figure 1－1． The uptake of moisture by
textile fibers usually occurs in accordance to the isotherm shown as Type
II， with an occasional tendency towards Ty’ 垂?@III． lt is not necessary to
dうscuss i・d・t・il h・・e th・th・・retical・i．9酬cance・f th・φff・ren．t tyPes・
but－some indication of their origin may be desirable， if only to provide
a theoretical framework in which to fit the facts to be presented．
It is generally agreed that the Type 1 isotherm is characteristic of
sorption where the substance forms only a unimole．cular layer on the substrate，
but there is more difference of opinion with regard to the remaining types．
According to an all－embracing theory，14） the Type II isotherm is characte－
ristfic of multimolecular sorption where the attracti．ve forces between the
sorbing and the sorbed substances are greater than those between the mole－
cules of the sorbed substance in the l iquid state， whereas the 丁ype III is
obtained when the forces between sorbing and sorbed substances are relatively
small．． Type IV and Type V isotherms are obtained when the simpler relation一
一5m
ships are coinplicated by t．he occurance of ’capillary condensation’． Accor－
ding to other more circumscribed views，i5’i6） an isotherm of Type u， in，
which we are prin．cipaMy interested， is the resul’t o’f twosimultaneously
occuring processes， direct chemical combination of water molecules to fiber
mo］ecules producing on’e curve， while a ］ooser binding by van der Waals forces
or fin solution proyides the other； the sum of the two effects provides the
composite sigmoid curve， as shown in Ffigure 1－2．
During a few decades sjnce as early as 1920， the moisture sorption
behavior of texbile fibers was studied in terms of the absorption and
desorption isotherms by a number of au’しhors for some natural and regenerated
cellulose fibers； such as by Urquhart， Williams and Eckersall for raw and
soda－boiied cottons，3’11’17－24） by oguri， Nara and Terui for cotton and
viscose rayon，25－27）’ ≠獅п@by Neal， Brownsett anci Farrow also for soda－boi］ed
cotton，28－30） and speakman and cooper for wool．31 “一33） An of these fibers
are composed of hydrophilic polymers and－have relatively high degrees of
hygroscopicity， so that the isotherms were significant not only in an academjc
sense to study the interaction between the water molecules and fiber mole－
cules， but also from a technical view point of determining the official
regains for trading the fibers by weight．
After．．．the pioneering stud」es of the absorption and desorption isotherms，
as rnentioned above， numerous investigations have been devoted mostly for
natural and regenerated fibers and for synthetic fibers of hydrophVic
po，lymers， such as nylons and polyvinyl alcohol； i．e．， in a decade of 1940，
1）
by Bull for several kinds oi protain fincluding s’ilk fibroin， by Rowen
and Balaine for moisture and nitrogen absorption on cellulose fibers， wool，
・ilkr・岬・・6－6，34）by H・・hi・…d Y・m・t・f・r ・yl・n．6，35）and by H・tt・・
and Gartside for raw silk and s“k sericin． 36） ln a decade of lgso， Taylor
has investigated the sorption isotherm of viscose rayon and mercerized cotton
一6一
（，。da－b。“，d、。tt。，）。ith、peci，1，ef・，ence at 1・w h・。iditi，・、1り2・37）Yan。
has finvestigated tAe sorption isotherrn of poiyvinyl alcohok38） and Thompson，
Highes and Fordyce have studied the moisture sorption equilibrium as well
as kinetics for’ 翌≠狽?秩@soluble po］yme“s of ceMulose ethers．39） same sort
of studies on the sorption isotherrn has been continued by Kataoka for cellulose
acetate fibers，40） by Beever and’ ualentine also for cellulose and cellulose
acetate fibers with special reference at interval and integral sorptions of
。、ter vap。鵬4ト43）and by St、p1， f。剛，c。、e，、y。n at sat、，at」。，，eg、r，
d，d、ced f，。m d，，sうty・、，d，w，m，g d、t，．44）エ， a decad，。〔96・， J，fferう，、
has ipvestigated v’ ?窒凵@comprehensively the sorption isotherm for cellulose
45－48）
and eight other texti］e polymers， and Daruwalla and Shet have extended
the interval and integral sorptions of water vapour on cellulose and ce］lulose
acetates．49） Newns has carried out moisture sorption studies of regenerated
ce？lulose extensively in terms of sorption kinetics for almost two decades sO－54・）
frovn mi d－1950．
Theo’retical approach fo，r explaining the mois’ture sorption fisotherm of
textile fibers in terms of different sorption mechanisms， was originated．
byP，ir、ef。，c。tt。，う，1929．15）H，。，deam。、tう。p。，t、nt、。，励、tう。，t。
the theory by postu］ating two possible forms of adsorbed water， one （alpha
form） chemically bound to cel lulose molecules and the remender （beta fo．rm）
adsorbed in 1’iquid form， as demonstrated in Figure 1－2，，i．e．， two－phase
adsorption theory． The theory was modified by Speakman adding the third
form of water in capiHary condensation for the sorption isotherm of wool
fib，r，．A55）1．e．，three．ph，、e、d、。rpti。n th，。，y．丁h， t。。．。． th，ee．ph，se
theory was replaced with rnultilayer adsorption theories， which are essentially
the same Sn cohcept as the multi－phase adsorption theories， but are more．
realistic in adsorption me’ モ?≠氏Djsms as represented．’by． ，Bruneuer，．Emmettee
56）
and Teller （BET） theory．
［1@7 e一
The BET theory 一is sirnply to extend the Langmuir’s unimolecular
adsorption theory，57） dynamicaMy balancing the evaporatton and condensation
of water molecules from and onto the surfaces．of substrate， to mul，ti］ayers
of adsorbed molecules， and has been generally accep’しed to give a reasonably
accurate acco，unt of the adsorpbion process． It does fit textile isotherms，
except at high hunidities at which several modifications have been suggested
to account for ．this discrdpancy． The BET theory has been dfiscussed by
cassie，58，59） Gilbert，60） and Hil161） largely with respect to the structure
of the outer layers of adsorbed water， on the basis of thermodynamic approach．
The discrepancy of the textile fisotherm at high humidities frorn the BET theory
has been discussed not only by taking into account the capUlary condensation
mechanism， but also by restrains on polymer swelling to yield a hydrostatic
pressure acting so as to reduce the observed vapour pressure to that for
unconstrained absorption．58） A similar theory of，restrain has been recently
employed by Newns in a study of absorption－desorption kinetics of regenerated
cellulose．50）
Despite of a great development of synthetic fibers following the first
invention of nylon 66 fiber by Du Pont in 1938， relatively few investigations
of the sorption isotherm have been performed for the synthetic fibers．
This is becaUse most of the synthetic fibers being composed of hydrophobic
polymers， such as poly－alpha－olefins， polyacrylonitrils， and polyesters，
and having relatively low degree of hygroscopicity． Recently， however， a
special group of synthetic fibers principally composed of hydrophobic
polymers， has appeared with a relatively high degree of hygroscopicity， possibly
owing to chemical and／or physical modifications of the fiber structure as
a water adsorbent． Therefore， it is a time to activate the studies of sorption
isotherm Of textile fibers， again， with a particular emphasis of investigating
the interaction between water and textile po］ymers， especially the charac’1 er
一8一
ヰand， comsequently， the structure of the adsorbed wa te r・『 by means of some
novel techniques， such as mic｝【o－ca］orimetry and／or mo］ecular spectroscopy
being able to character「ze the nature of the adsorbed water experjmen’しally，
rather than theoretically．
In this disertation， therefore， ’じhe absorption and desoγ’ption isothers
of twelve kninds of cellulosic fiber will be first observed under various
condit「ons， and then the isotherms will be analyzed in terms of the BE丁
equat「on， not only to quantify the isotherms in terms of the parameters of
the equation， as closely as possうble， but also to examine the physうcal
meani・g of th・p・・am・t…r・・e1・㌻i。・t・wid・ly va・壌ed伽e・truct・re
of the spec「mens。 Finally， the natuγ・e and the structuγ・e bf adsorbed water
will be investigated expe酉mentally be means of the novel techniques， a
differential sc．anning calorlmetry and a h「gh－resolution nuclear magnetic
resonance spectroscopy， in order to solve the most fundamental problem
ln the BET equation； i．e．， the structural characterization of the outer
layers o’f the adsorbed water， γ・eally in contrast e窪ther to the so－called
free water， to the capillary－condensed water， or to the restrained water
accompanied with swelling pressure of specimen at high relative humid「一
tうes．
＋Th， w・・d・d・。・pti・・i， used t・d…t・the attach…t・f・・t・・t・specifう・
sites as distinct from the random m「xing of molecules which occurs 「n
SOlution．
．9 一一
℃①§250εく
（1） （耳） （皿） （IV） （V）
iv一 Pressure一一一一一一一一一一L
Fi uu r， e 1 一1’ ． F fi ve ty pes of ・ so rpti on i sotherm ．
v
．．． ID， ¢
［ U
02甲⊂Φり
」Φα
こ
巴巴
Φ10ヨ．至
。
Σ
0
Cotton at
嘱
Q5。c l l
@ 1
@ Total water@ sorbed
1
ノ’I
，＿一4一一一一 一 ＿ 一 哨 一 一 一 一
va堂er in
Dissotved@ater
@hydrate
20 40 60 80 100Retative humidity per cent
Fi’gur・ e 1－2． Composite sigmoid absorption curves
ヨ リ 一 ロ 一
Ref＝erences
1） M． Bu11， 」． Amer． Chern． Soc．， 66， ］499 （1944）．
2） A．F’． Mellon， A．H． Korn， and S．R． Hoover， 」． Ameγ・． Chem． Soc．， 69， 827
（1947）； 70， 114 （1948）．
3） A．R． Urquhaγ・t and A．M． Williams， J． Text． Inst．， 15， T138 （］924）．
4） S．W． Benson， D．A． Ellis， and R．W． Zwanzi9， J． Amer． Chem． Soc。， 72，
2102 （1950）．
5）」．W． M、B，i， and A．図． B、，k， J． A。，，． Ch，。． S。c．，48，．U90（1926）．
6） J．M． McBain， S．J． Good， A．M． Bark， D．P． Davis， H．J． Wi］1avoys， and R． Buck「ngham， Tγ・ans。 Faraday Soc．， 29， 1086 （1933）．
7） S．L． 図adorsky， Rev． Sci． Instrum．， 21， 393 （1950）．
8） P．M． Hauser and A．D． McLaren．， Ind． Eng． Chem．，月旦， 112 （1948）．
9） D．K． Ashpole， Pγ・oc． Roy． Soc．， A212， 112 （1952）．
10） 」．B． Speakman， 」． Soc． Chem． Ind．， 49， T209 （1930）．
］1） A．R． Urquhart and A．M． Wう11うams， 」． 丁ext． 工nst．， 15， T433 （1924）．
12） J．B． Taylor， 」． Text． Inst．， 43， T489 （1952）．
13） J．B． Taylor， 」． Text． Inst．， 45， T642 （1954）．
14） S． Brunauer， 1匪Physical Adsorpt「on of Gases and Vapoursu， Oxford Univ．
Press， 1943， PP． 149 et seq．
15） F．T． Peiγ℃e， 」． Text． Ins’し．， 20， T133 （1929）．
16） A．J． Hailwood and S． 卜｛orrobin， Trans． Faraday Soc．， 42B， 84 （1946）．
17） A．R． Urquhart and A．M． Williams， 」． Text． Inst．， 15， T559 （1924・）．
18） A．R． Urquhart and A．M． Wi11．iams， 」． Text． Inst．， 16， T155 （1925）．
19）A・R・U・q・h・・tand A・M・Wmr・m・・」・Text・lh・t・・1ブ・T38（1926）・
20）A・R・U「quha「t・」・Text・lnst・ D・18・丁55（1927）・
2］） A．R． Urquhart， J． Text． Inst．， 20， T119 （1929）．
22） A．R． Uγ、quhart and N． Eckersa11， J． Text． Inst．， 21， 丁499 （1930）．
23） A．R． Urquhart and N． Eckersa11， J． Text． Inst．， 23， T163 （1932）．
24） A．R． Urquhart and N． Eckeγ・sa11， J． Text． Inst．， 23， T135 （1932）．
25） S． Ogur「 and M， Nara， Kogyo Kagaku Zashi， 33， 777 （1930）．
＿ 1つ ＿ 凸L
））））））））））））））））ヘノ））））））））㍉ノ））
S． Oguri and S． Terui， Kogyo Kagaku Zashi， 3．4．， 515 （193］）．
S． Oguri and S． Terui， Kogyo Kagaku Zashi？ ．ILt， 630 （1931）．
S．M． Neal， J． Text． lnst．， 22， T320 （1931）．
S．M． Neal， J． Text．’ hnst．， 22， T349 （1931）．
T． Brownsett， F．D． Farrow and S．M． Neal， J． Text． lnst．， 22，
J．B． Speakrnan and C．A． Cooper， J． Text． lnst．， 27， T183 （1936）
J．B． Speakman and C．A． Cooper， J． Text． lnst．， ．ZL7， T186 （1936）
J．B． Speakman and C．A． Cooper， J． Text． lnst．， 2Z， T191 （1936）
H．B． Rowen and R．L． Blaine， Ind． Eng． Chem．， 39， 1659 （1947）．
K． Hoshino and K． Yumoto， Nippon Kagaku Zashi， ．Z90．， 104 （1949）．
E．A． Hutton and J． Gartside， J． Text． ｛［nst．， 40， 丁16］ （1949）．
J．B． Taylor， J． Text． lnst．， 47， T147 （1956）．
Y． Yano， Nippon Kagaku Zashi， 76， 668 （1955）．
L．J． Thompson Highes and D．B． Fordyce， J． Polym． Sci．，
Kogyo Shikenjo Iho， ＃46， 7 （1958）T． Kataoka， Sen－i
D．K． Beever and L． Valentine， J．
D．K． Beever and L． Valentine， J．
D．K． Beever and L． Valentine， J．
M．LL Staples， Tex’t． Res． J．， 28，
R． Jeffries， J． Text． lnst．， 51，
R． Jeffries， J． Text． Inst．， 51，
R． Jeft’ries， J． Text． lnst．， 51，
只・」e飾師J・Appl・P・］ym：S・『・
E．H． Daruwalla and R．T． Shet， Text．
A．C． Newns， Trans． Farday Soc．， 52
A．C． Newns， J． Polym． Sci．， 41， 425
A．C． Newns， Trans． Faraday Soc．，
A．C． Newns， J． Chem． Soc．， Faraday
75つ」 ● ・ ・
T）））
（1931）．
22， 509 （1956）．
Iho， ＃46， 7 （1958）．
Appl． Chem．， 8， 103 （1958）．
Text． lnst．， 49， T95 （1958）．
Polym． Sci．， 32， 521 （1958）．
900 （1958）．
T339 （1960）．
T399 （1960）．
T441 （1960）．
， 8， 1213 （1964）．
Res． J．， 32， 165 （1962）．
， 1534 （1956）．
（1959）．
64， 3147 （1968）．
Trans．， 1， 69， 444 （1973）．
） ） ）
4霞」だ0
［つ［JRJ）
）
）
700Qノ
［つ［」［」
）06
）ヨ6
一 13 一一
A．C． Newns， J． Chem． Soc．， Faraday Trans．，’ P， 71， 278 （1975）．
q．B． Speakman， Trans． Faraday Soc．， 40， 6一（1944）．
S． Brunauer， P．H． Emmett， and F． Teller， J． Amer． Chem． Soc．， 60， 309
（1938）． ， 一1 Langmuir， J． Amer． Chem． Soc．， 40， 1361 （1918）．
A．B．D． Cassie， Trans． Faraday Soc．， 41， 458’ i1945）．
A．B．D． Cassie， J． Soc． Dyers ＆ Col．， ”Symposium Fibrous Proteins”， 86（1 946）．
G．A； Gilbert， J． Soc． Dyers ＆ Col．， ”Symposium Fibrous Proteins”， 96（1946）．
T． HiH， J． Chern． Phys．， 14， 263 （1946）．
一 14 一
Chapter 2． Brief Survey on the Basic Theories of Sorp．tion． Isoth．e－r． rn． 一〇．一f．
Textile Fibers
There have been several theories that attempt to explain the adsorption
of moisture by textile materials． This fis due partly to our lack of knowledge
concerning the sorpti’ 盾氏@process， but also to the absence of any ’ モ窒撃狽奄モ≠
test th№煤@may be appl icable to each the．ory． lt is re］atively easy ，to deveiop
a sorption isotherm to fit the experimental relation with the aid 6f two
or three adjustable parameters， but this is not necessarily a sufficiently
exacting criterion on which we can judge the theory． We can only ensure
that the theory does not violate any physical prin．ciples which have been
accepted．
The theories fall roughly into two groups． peirce，1） and Brunauer，
Emmett and Teller，2） for example， consider the water molecules to be adsorbed
on il！t［！！glznterna］ s u rfaces or E一！t l！esLtes i n the a d s orbenP， a n d a pa rt from s upplying
these siles the textile fis considered to play l ittle part in the process．
On the other han，d， Katz，3） and Hailwool and Horrobin，4） consider the process
to be one of solution． lt is probable that both these l ines of approach
are correct， the former at low water concentratiop， and the iatter as we
approach saturation．
It is about fifty years since Peirce developed the first adsorption
isotherm for textiles in order to explafin the effect of adsorped water on
the elastic properties of cotton． As mentioned in the previous chapter， he
made a most important contribution to the theory when he postulated two
possible forms of adsorbed water， one chemicaHy bound to the cotton， and
the remainder adsorbed in l iquid forrn． This concept has been employed by
all succeeding investigators・『n the fie］d． 丁his theory has been， however，
criticized by Gilbert5） on the grounds that there is no microscopic balan－
cing of the evaporation and condensation processes， in accordance with the
。． 1員 ＿ 1㍉ノ
theories of Langmuir6） and Brunauer， Emmett and Teller （BET）．2） ln fact，
Peirce derivation is not clear at several points， but it has suppl ied
many basic ideas for later workers， and such as its value can not be
overesimated．
Hailwood and Horrobin4） have developed a sorption isotherm by analogy．
with simple solution theory basing on standard thermodynamics． They consider
that the adsorbed water exists partly in chemical combination with the
polymers， as water of hydration， and partly in sol id solution． Furthermore，
the three spcies， namely polymer， dissolved water and polymer hydrate， are
considered to form an ideal solution， ln their derivation the authors con－
sider the general case with ！llgtnLgi2gtggEL－g！一bxEing！一ignny degrees of hydration， but for si．mpl fi c i ty
it is proposed to take the case where the monohydrate only is formed； the
principles involved are not affected by this modification．
In spite of the good descripbion of experimental data， such as th’e
heat ok wetting observed by Hedges for wool （keratin 一 water system），7）
with the above model by Hailwood and Horrobin， it has been criticized by
Gee and Barrer．8） The main criticism is that the splid solution can not
be considered as fi deal， especially when spec「es o’f to’しally different molecu］ar
size are included． Solutions pf long－chain polymers are known to differ
considerably from ideal solution． Cassie9） has questioned the doubt cast
on Hedgesis experimental data for heat of wetting， whfich he considers to
be the most reproducible data available for the keratin 一 water system．
Ei℃」109」髭≡と＝三＿E田胆∈III1｝＿9E⊇璽＿1皇ll∈iと⊃⊥§＿lbggrこ∠＿gf＿6望§9tp1190＿工§9主bg12胆
As long as 1918， Langumir6） developed a sirnple theory o’F sorption
limited to the formation of unimolecular layers on sol id surfaces． He did
this simply by equating the rate of evaporation of gas molecules from the
surface with the rate of condensation from the surrounding gas or vapour．
Very simply then， the rate of evaporation wi11 be proportional to the
．一 16 一一
surface covered by，adsorbed molecules （Aa）． The rate of condensation will
Pe proportional to the uncovered surface （Ao） ’and the vapour pressure （p）．
Therefore，
k’aAa＝koP Ao ’ （1．）If the total surface 6re is A（＝ A一 ＋ AA）， then
a o
kA A e p一一一一一g－L’ ＝k＝＝kdv （2） koAo （A 一 Aa） （1 一 e）
where e（＝ Aa／A） is the fractional adsorption for a pressure p， and k is
the ratio of ’汲＝^ko． This relation gives the well－known isotherm which
describes only some adsorption processes， the more general shape befing more
like the hormal textile regain curves wfith a point of inflection， as shown
in Fig． 2・一1， can not be predic’ted．
one is， therefore， led to c6nsider adsprption in amounts greater than
the monolayer． Langmuir did extend his th’ ?盾窒凵@in thfis way， but did not
derive an isotherm． Many years later， however， Brunauer， Emmett and Teller
（BET）2）devel。P，d，m、1tう1、y，，6d、。，pti。，。echani、。、翻、， t。 th、t。f
Langmuir and extended fit to derive a multimolecular adsorption isotherm．
The method is simply to extend the evaporation 一 condensation mechanism to
many layers of adsorbed molecules． ．
Consider a surface covered by groups of molecules； there will be free
surface together with groups contafining 1， 2， 3 etc． Iayers of molecules．
Let Ao be the area of uncovered surface， Al be the area covered by one l ayer
molecules， and Ai be the area covered by i layers ef molecules； i．e．， the
molecules can be arranged as shown in Fig． 2一一2， schematically．
For equilibrium one may equate the rates of evaporation and condensation
from successive layer， and for the first layer it follows
一 17 一一
alp Ao＝klAl ， （3）and the general expression is
aip Ai－1＝kiAi 一 一 （4）
The coeffic’ 奄?獅狽刀@ki inc］ude a term which governs the rate of evaporation
of the adsorbed molecu］es． These can leave the surface only if they acquire
an energy equal to the energy of bindfing to the surface．
The fraction of molecules acquiring the necessary energy at any instant
wiH be given by Boltzmann’s expression as exp（一一UVRT）， where U’堰@is the
binding energy for the i－th layer， R fis the gas constant， and T is the
absolute temperature． Therefore， one can write
kl ＝bl exp（一UVRT） ， （s）
and in general
ki＝biexp（一Ui／RT） （6）where b］， b2， b3， etc． are constants．
The total surface area Ao’ can be given by
co
Ao’＝Z Ai （7） o
and total volume adsorbed v
co
v＝ vo Z i Ai （8） o
where the area Afi is covered with i l ayers， and vo is the volume of gas
adsorbed per unit area of monolayer． Therefore，
一18一
co
v z fi A．
一 〇 1
‘vA）＝v／v－a ＝一 （9） v／（A o o m oo
v z A． O l
o
BET now make two assumptions； （1） that U2 ＝ U3 一一 一：一丁一一 UL （heat Of
liquefaction of gas）， （2） that b2／a2 i b3／a3 ＝ 一一一一一一 d， i．e．， they’ assume
that the adsorbed gas is in a l iquid state from the second layer outwards，
so that the evaporation 一 condensation－mechanism is similar for all layers
except the first layer． Thus， one can write A2 ＝ x Al， or in general
Ai ＝ x Ai．1， where
×＝ （p／d） exp（UL／RT） （10）
and for the first layer Al
C ＝ （aVbP ．d exp［（Ul
＝ A．．C x，
o
一 UL）／RT］
where
（ll）
Therefore， the following relations may be deduced for unresticted
adsorption of infinite layers：
（v／Vm） ＝
ココ
A
曾－
○○
ｰ0
Al ＋ 2A2 ＋ 3A3 ＋
oo Ao ’ Al ’ A2 “ A3 “ ”“一一一’
1へ
Al（1 ＋ 2x ． 3，2 ．一 一一一一一一一一）
Ao “ A］ （1 ＋x ＋ x2 ＋ ．一一．．．）
A。C・臼／（、一x）2］
Ao［1 ＋ Cx／（1 一 x）］
一19一 一
cx
．一 ． （12） （1 ・一 x）（1 一 x ＋ Cx）
At saturation （p ＝ ps） v ＋ oo． But v ＋ oo when．x ＝ 1－in the above
expression for the isotherm given by Eq．（12）， so that from Eq．（10） it
foU ows
X＝ （p／d） exp（ULIRT） （13）
For v f oo， x ＝ p／ps， and
，．L．CP （14） （p， ’ p）［i ＋ （C T ，i）p／ps］
If the adsorption js restricted to a finite number of molecular layers，
the following relation may be obtained：
v－c x i 一 （n．＋ i）xn’＋ nxn’i
v＝一1－i’i1iinyib一一」IV iN 一ii－ti－iiLt一一zil’i－rL6”Vli；ri（c．i），．ckn＋ （i5）
where n represents the maximum number of adsorbed molecular layers which
can be built up and is compa ti ble with space l imitations． 工t 「s noted that
the Eq．（15） reduces to Langmuir’s eauation， Eq．（2） for monomolecular
adsorption when n ＋ 1．
The above relation of Eq．（14） may be put in a l inear form
p／v（p， 一 p） ＝ o／v．c） ＋ 一一12－v：’E ！ci （p／p，） 06）
m
and by ploting p／v（ps 一 p） against （p／ps）， vm and C may be determined from
the s］op and fintercept． But vm ＝ Ao’vo， where Ao’ is the total area avai－
lable for adsorption． Therefore， if vo can be estimated， it is possible to
determin A ’． o
一 20 ．．
NoWs
C・（・1／bl）（b2／・2）exp［（UドUL）／RT］ 『． （17）
and BET assume that alb2／a2bl ＝ 1． Therefore，
C・exp［IUドUL）／RT］ ． （18）
from which one mqy determine the heat of absorption of the first layer．
H。weve，， C、ssi，IO）h、、。bt、i，，d、， exp，essう。， f。， C，mp1。yi，g，th，，。。dyna而・
treatrnent and given reasons to suggest that alb2／a2bl 〉 1， and as a result
the values for the heat of adsorption by BET equation of Eq．（18） may be too
low．
The BET theory of sorption is generally accepted as giving a reasonably
accurate account of the adsorption process’． It does fit textile ibotherm，
except at high vapdur pressures nea’r saturation， and many mod’ifications
have’@been suggested， a’刀@will be discussed in a later chapter， to account
for this discrepancy．
The BET theory has been discussed by cassiell） and Gilbert，5） largely
with respect to the structure of the outer adsorbed layers． BET allow only
short－range forces sufficient to bind the first adso’窒b?п@layer； further
layers are adsorbed at vapour pressures below saturatio，n by virtue of a
と・hd・・s・ti・n－evap・・atr・n eq・111b蘭・At th・・am・t加・・h・wever・BET
consi，der that the adsorbed water over and above the monolayer has the
properties of liquid water． These two considerations are incompatible，
because， as Ca’唐唐奄?@has pointe’п@out， no adsorption could take place on the
external layers if they’@were identical with l iquid water． Thesb could be
no result’奄獅〟@decrease in free energy bn transferring water molecelues from
liquid wate’秩@to the outer adsorbed layers． It is also apparent frbm inspection
of the BET model that the outer layers of water molecules are distributed
21
in a manner completely different from t，hat in l i’quid water， i．e．， in a rnore
ordered state than ．in a random state of l iquid． The terminology of internal
surface upon which the mono一 and multi－laye・rs of adsorbed molecules are
built－up， seems to be visua］ized as a model， but fis difficult to．understand
unless the existence of any internal rnicrocleavage or microvoid is examined．
工b§〔田g鯉躯1⊆．aE2塑gb．19一合鯉ご匹ユ9し王§匹b卿
In the absence of long－range forces binding these outer layers to the
surface， the adsorption of vapours on sol ids has received justification only
on the thermodynamic grounds； Brunauer， Emmett and Teller argue that there
are no such long－range forces present． According to the law of thermodynamics，
adsorptfion must take place only if the absorbate suffers a reduction in
free energy on befing transferred from an external l iquid to the absorbed
state．
丁he change うn free energy at constant pressure is
AG－A’H 一TAS ． （1 9）
where △卜｛ is the heat exchange per mole， △S is the entγ・opy exchange per mole，
and T is the absolute tempe’ 窒≠狽浮窒?D
For a reduction in free energy， AG must be negative， and even if AS is
zero or negative； i．e．， the absorbed molecules are in a more ordered state
than in the l iquid， then， provided that AH is negative （i．e．， heat is evolved
in the adsorPtion process）’， adsorpbion can st“1 take place． However， ii’ the
heat evolved is from water adsorbed in the first layer only， then for
subsequent layers where AH ＝ O， in order that AG be negative， AS must be
positive． ln other words， adsorption must then take place because the
adsorbed molecules are in a more random state than in l iquid water； G．e．，
by some mixing or distributive process analogous to the BET evaporation 一一
condensation mechanism．
一22一
Cassie first developed a theory of multimolecular adsorption on these
line and showed that the resulting isotherm relation was equivalent to that
of BET．11） He did not postulate adsorption on internal surfac－e． s一， but con－
sidered adsorpt『oA sites d「strうbu’しed throughout the polymer． On these sites，
water molecules can combine chemically with the polymer with， evolution of
heat， one coTT｝bined mo］ecule to a site， whilst the remainfing water exists in
a ljquid state adjacent to these occupied sites to form a sort of water
cluster． Cassie．’s original derivation of the resul．ting free energy increase
in the polymer phase was critieized by Hill12） to be incorrect， although
the final isotherm relation was correct． What is essentially Hillis derivation
is therefore discussed below．
SupPose there are B mo］es of．adsorption sites per a given しmit
mas’s of textile polym’ ?窒刀D Then we first consider the distribubion of A moles
of water over’ @these sites in such that X moles are combined． The remaining
（A 一 X） moles exist in a l iquid state with their entropy increased by
distributing them over thd × occupied sites， allowing any ’number to each
group． We can then write
z）1GA＝AGx＋AG（A．一×） （20）
where AGx is the free－energy change due to the distribution of × moles
on B l oW－energy sites， and AG（A－x） is the free－energy change due to the
distribution bf （A 一 X） moles on the X occupied sites．
AGx is made up of a heat term， ！xHx（＝ wX） where w i s the heat of reaction
between l iquid water and the low energy sites （heat is evolved， so that w
is negative）， and al so an entropy term given by
T！tsSx＝RT（ln Cx ＋× l n j，） （21）
where js is the partition function for the bound water molecules， and is
＿ つR ＿ 』㌔ノ
determined by the number of ways that the energy may be distributed amongst
the available degrees of freedom．， Cx is the number of ways of distrib’ @uting
× moles on B sites， i．e．，
cx＝一?Iill一×）！k一一 一l」ll：B．〉（）（B一×） （22）
Hence，
iesGx ＝ A，Hx 一 TASx
＝ 一RT［BlnB 一 ×lnX 一 （B 一 ×）ln（B 一 X） ＋ Xln．」， ＋ wX／RT］ （23）
△G（A－X＞．・…「・t・・f・ne・t・・pyt・m・nly・s輔a「淫nfomt・Eq・（21い・e・・
TAS（A一×） ＝ RT［lnC（A一×） ＋ （A 一 X）lnjL］ （24）
where C（A一×） is the number of ways of distributing （A 一 X） moles on × sites
allowing any number per group．
C（A一×）＝一~！A一
ili－r－il－I」一1／一一一L＝fut ft一×）（A．．×） （2s）
Therefore，
△G（A．XドーRT［Al・A－Xl・×一（A－X）1・（A－X）・（A－X）1・jL】（26）
Summing the tw’o terms，． we obtain the total free－energy change． Then，
for equfilfibrium between the two distributions we determine the condition
that AGA fis a minimum for a given value of A， i．e．， 5AA／BXA ＝ e． The
condithon is
2 （A 一 X）（B 一 ×） 一Y× （27）
where ’y ＝ （jL／js） exp（w／RT）．
一24一
N．ow， in．order to determine the isotherm relation we equate ’the chemical
potentials of rnolecules in the．．vapoyr．’and adsorbed phases，．i・e・， ’vv ＝’vA
where’ 魔磨@and vA refer to the vapour and adsorbed phases， respectively．
But， assuming the vapour to have the properties of．a perfect gas，
P，・・。・RT．1叩 ’ （28）
where vo is a constant and p the vapour pressure， and
μA・∂△GA／BA・RT 1・［（A－X）／A】一R丁1・jL （28）
Therefore，
Po＋
Also， for
RT lnp ＝ RT ln［（A 一
equilibrium between
x）／A］ 一 RT lnjL
a pure l iquid and its vapour
V。・RT 1叩s＝一RT 1・」L
where ps is the saturation vapour pressure． Therefore，
（P／Ps） 一 （A 一 X）IA
and， combining this with the equilibrium condition given
obtain the isotherm relation
（29）
（30）
（31）
by Eq．（27）， we
Bp
A一一一 （32） （p， 一 p）［y ＋ （1 一 y）p／p，］
It shoul be noted that this equation is essentially the same as the
BET isothe’ 窒香@given by Eq．（14）， explaining the BET constants fin terms of
thermodynamic parameters， since A／B ＝ v／vm， alb2／bla2 ＝ js／jL， and C ＝ 1／y・
From a thermodynamic point of view， it is essentially jmportant to inves一
’tigate the chahge in ’entropy’ AS during the process’ @of ．vabour． adsorption in
一 25 一一
order to characterjz’ ?@the structure of the ou，ter． adsorbed．layers i－n the
sense of BET adsgrptfion． mechanism；．，m． or．e，．o．rdered ．pr－les．s． ordbred－than．．the
structure of water in the l iquid state．
一26一
e
Adsorption isothermfor texti｛es xi
Langmuir
p
Fig． 2－1． Comparison of adsorption isotherm of Langmuir’s
monornolecular layer to that of textiles．
27一
：こ＝＝＝＝
＿剛一．ご＝
o一 一 ， 軸
40 ．A ’42． 頑3 ノ44 ・45
surfaces．solidonadsorptionMulti－1ayer2－2．Fig．
一 28 一
References
）） ） ） ） ））））））
12．3 4 5 678901
■巴11
）21
F．T． Peirce7，Jr Text． lnst．． ．ZLO， T133，（1929）．．
S． Br’浮氏f ≠浮?秩C P．H． Emmett， and F． Tdller， J． Amer． Chem．． Soc．， 60， 309
（1938）． 一一一J．R． Katz， Kolloid Beih．， 9， 1 （1917－18）； Trans． Faraday Soc．， 29， 279（1933）．． ． 『 ． 一
A．J． 卜｛ailwood and 事． Horrobin， 蛙General Discussion on Swe11うng andShrinking”， Trans． Faraday Soc．， 42B， 84 （1946）．
G．A． Gilbert， J． Soc． Dyers ＆ Col．， Symposium ’Fibrous Protejns’， 96（1946）．
1． Langmuir， J． Amer． Chem． Soc．， 40， 136］ （1918）．
J．J． Hedges， Trans． Faraday Soc．， 22， 178 （1926）．
G． Gee and R．M． Barrer， Trans． Faraday Soc．， 42B， 84 （1946）．
A．B． D． ．Cas’sfie， Trans． Faraday Soc．， ！LZtE－B， 84 （1946）．
A．B．D． Cassie， T．rans． Faraday Soc．， ±1 ， 458 （1945）．
A．B．i Cassie， J． Soc．’ Dyers ＆ Col．， Symposium’ ’Fibrous Proteins’， 86
（」946）．
T’D Hill， J． Chem． Phys．， 14， 263 （1946）．
一29－
Chapter 3． Apparatus Constructed for Measuring the Sorption lsotherms
Two types of apparatus both basing on gravimetric method； a weighing
bottle method and a sorption balance method with quartz sprjng in vacuum，
as sch6matized in Ffigs． 3－1 and 3－2， respectively， were constructed for
measuring the moisture absorption and／or desorption isotherms of fiber
specimens． The weighing bottle method was originated by Urquhart and
wiHiamsl） and modified by several authors．2－9） This method has been most
widely used because of its simple handl ing． A weighing bottle containing． a
mass of a fiber specimen is kept within a closed chamber， such as a desiccator，
and the fiber specimen is condi’しioned under a given temperature and a given
vapour pressure adJ’usted by an aqueous solution of sulfric acid at a given
concentration o“ by a saturated aqueous solution of a given inorganic salt．
Usually， it takes ’＝@time as long as at least a week until an equilibrium of
moisture absorption or desorption of the fiber specirnen is attained， especially
・when the equilibrium value approaches a saturated value of moisture content
and where some stirring of atmosphere within the closed charnber by a fun
mea2irt be recommended．
1・目9素3・re・h・w・g・・phi・・1 rel・ti。・s。f th・・el・ti・e h・midity（frac－
t．ional vapoqre pressure to saturated vapour pressure at a given temperature）
ef atmosphere withfin the closed chamber to the specific gravity of the aqueous
sol’ution of sulfric acid at five different temperaturesg 10， 20， 30， 40， and
5・oC，・11，ep1。tt，d f，。。 th，エ，t。rn、tr。，ai C。itical T、bl，Jo）1， practice，
a set of twelve desiccators differing in the concentration of sulfric acid
contained a’獅п@consequentl’凵@covering a whole range of relative humidity of
the atmosphere from O to 100e／o， is prepared so as to determine at once the
absorption or desorption isotherm over the whole range of relative humidity
for bone－dried or wet specirnen， respectively． The dgsiccators are stored
in a huge constant temperature air－bath controlled by forced afir－flow of a
一30－
gi、e・t・叩erat・・e wlth・・．a6cu・・cy・f士．10C． M・i・t・・．e up．t・ke at．the eq・i－
1ib・i・m i・ the・b…ptう・…d 秩cpt「・・pゆcess l・・ep・e・e・t・d by．1％一・・g・’・’
which can be defined as
mass of moisture up－take
9，一regain ＝ 一 x 100 （1） unit mass of bone－dried specimen
Fig、，含天2 r、 a，ch。。、ti、 d蜘d。由。ISt脚g、p晦。痴f th，、。，ptう。，
balance method with quartz spring in vacuum orig3nated by McBain6’7） and
modified by otherg；9’ii’igy） which the change in weight of the sampie （fiber
specimen） during the moisture absorptipn or desorption process can be rneasured
continuously in terms of the change in length of the quartz spring with lapse
of tGme until the equilibriurn is attained at a given vapour pressure and a
given temperature． For performing the measurement， every cock， “iith exception
of the Cock 5， is opened and the whole system is evacuated by a vacuum pump
up to a high－vacuum in the order o’ ?@，lo．T4．N一一5’ ． torr．to dryT－up the，，whole．sy，stem．．
including the sample， for gxample， for the measurement of．moisture，aPsorption
P，。cess。f b。・e－d．16d、pecimen． Aft，， d，yi，g．。f． th¢き．peci。，，考、．蜘16毛，di
the Cocks 1， 2 and 4 are closed whereas the Cock 5 is opened to evaporate
a given amount of water into the vapour reservoir with a given vapour pressure
which can be measured by the manometer． After closing the Cock 5 and openjng
the Cock’ Q， thb water vapour in the vapour reservoir is transfered into the
specimen chamber， and the moistUre adsorption process can be investigated by
a travellfing microscope fin terms of the change in elongation of the quartz
spring as a function of time．
Comparing the two methods with each other， the sorption balance method
has advantages， not only of being able to measure the absorption or desorption
process as a function of time， but also of attaining the equilibrium of the
process much faster than by the weighing bottle method； say usually within
一 31 一’
several hours in contrast一 to several days， at least， by，the wei，ghing bottle
method． Qn the other hand， the sorption bal・ance method with ・／q．uartz／一spring
has a disadvantage’ 盾?@not necessarily keeping the vapour pressure of－the
whoie system at a given constant ’魔≠奄浮?@during the course of the processes，ii）
unless the volume of the vapour reservoir is extremely large in’comparison
tb that of the other part of the whole system to minjmize the fluctuatiQn
of the vapour pressure due to moisture absorption or desorption of the specimen．
In Fig？；4 is shown a comparison of the absorption’isotherms of a bone－drfied
normal viscose rayon； one obtained by the weighing bottle method at a given
temperature of 30 ± 1 OC and the other obtafined by the sorption balance method
at a gfiven temperature of 30 ± O．1 OC． As can be seen in the figure， the
isotherms agree quite well at relatively low humidities less than about 400／，
relative humidity， beyond which， however， the isotherm by the weighing bottle
method deviates’gradually from that by the sorption balance method， always
showing a l ittle less values of regain as the relative humidity increases．．
This suggests that the absorption 一isotherm by the weighing bottle．．me．thod，一．
even after the conditioning as long as一 ’ ?盾宙黶@a week，’ itas not bden’ really’
achieved in an equilibrium state of mofisture absorption at high humidities．
Figur8A’一5 shows a block diagram of an apparatus constructed on the basis
of the sorption balance method wfith quartz spring in vacuum； a modification
of the principle in Fig．3－Q， not only to measure two absorption and／or
desorption processes at different vapour pressures， simltaneously， but also
to have an additional manometer with di－butyl phthalate， instead of mercury，
for performing the experiments at relatively low vapour pressures with high
accuracy． Figure3 奄U shows a relation between the readings of the two manometers，
mercury and di－butyl phthalate manometers， at various vapour pressures at
30．0 OC， indicating a good linear relation with a slope of density ratio
of mercury to di－butyl phthalate， （13．54／1．046）．
一 32 一一
Ffigure 3－7 shows galibration diagrams of quar－tz springs used； ．i．e．，
・1・ng・ti・・and dr・d一四rうght・el・ti・ns at 3・oC・・111・dうca伽g 9・・d linear
relations with the spring constants of O．2495， O．2012， and O．2283・gr／cm
for the ＃a ＃3and ＃4quartz sprfings， respectively．
一 33 一’
Captions for Figures
Fig． 3－1， Block ciiagram shoviflng the－gonstruction of．一a一・we－ighing bottlemothed
used for the measurement of moisture up－take of ’fiber specimen at
a given temperature and a given relative humidity．
Fig戟f 3－2 iil．OtChkq：la，gtlal］p7？．2；li：．：．a，’s，p，rlgfipig・of ．a sorpt」gn paian．cg／，me．thod
Fig． 3・一3． Diagrams showing relationships of the sbecific gravity of aqueous
solution of sulfr「c acid and ’しhe relative humidity of atmosphei（e
at five different temperatures．
Fjg． 3－4． Comparison of absorption isotherms of bone－dried norrnal viscose
rayon at 30 OC， measured by a weighing bottle method （open circle）
and by a sorpbion balance methpd with quartz spring in vacuum （dot）．
Hg． 3－5． Block diagram showing the construction of a apparatus based on
a sorption balance method with quartz spring an vacuum， where
Cs： cock， DBT M： di一一butyl phthalate manometer， D．P．： diffusion
pump， G．T．： Geisler Pube， Hg M： mercu－ry manometer， 1．G．： ion
gauge， LNG－bath：”1 h’quid nitrogen bath， Q．S．：一 quartz spring，’
R．P．： rotary pump， T．R．： trap， V．R．： vapour reservoir， and
W．R．： water resGrvoir．
Fig． 3－6． Cal ibration diagram showing a linear relationship between the
reading of rnerc’ury manometer and that of di－butyl phthalate
manometer at 30 Oc．
Fig． 3一一7． Calibration diagrams of three quartz springs， indicating good
linear relabionshfip between the elongation’ of spring and the dead－
weight hung with spring constants，
for ’the ＃ 2， ＃ 3， and ＃ 4 springs， respectively， at 30 Oc．
／
ts， H’ ’一
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Fig． 3一一1．
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50 60 70 80 90
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100
一 38 一一
40
Absorption Isotherm of Normal Viscose
Rayon at 30 Oc．
e ： measured by weighing bottle method
O ： measured by sorptfion balance method
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1．0 1．1 1．2
一 42－
References
1） A．R． Urquhart and Ar｝S． WiHiams7 J， Text’． lnst．， ．iLLt， T］38 （1924）；
2）H．B、1い． Amer． Ch，m． S。と．，．66，．1499（、944）．幽
3）1瀦1181．・献11靴and R・s・H。ove「・’ P・Ame「．・chem・soc・・69・827
4） ？iWggo？9nSOn， D・A・’t］，lis， and R・W・ Zwanzi－g， J． Amer． chem． soc．一， zg．t2， 2，lo2
5） J ’． L’1 ．i McBain i．一 andt A：iM； ’， Ba rkg ，」； Ame r； Chem． Soc． ，’ 48， 690： （1 926）．
6） J．Wr． 卜忙Bain，． S．」． Good， A．M． Bark， D．P． Davies， H．J． W「11avoys， and
B， Buck「ngham， 丁rans。 Faraday Soc．， 29， 1086 （1933）．
7） S．L． Madorsky， Rev． Sci． lnstrum．， L／， 393 （1950）．
8） P．M． Hauser and A．D． McLaren， lnd． Eng． Chem．， Lt， ］12 （1948）．
9） D．K． Ashpole， Proc． Roy． Soc．， A212， 112 （1952）．
10）“Internabiohal Critical Table”， Vol e 3’， p・303； G．H． Greenewalt， Ind． Eng． Chem．， Lt， 5？2 （1925）．
ll） 」．B． Speakman， J． Soc． Chem． Ind．， 49， T209 （1930）．
12）A・R・U・q・h・・tandA・M・Wmr・mS・J・丁・・t・エnst・，15・T433（1924）・
13） J。B。 Tayor， J。 丁ext。 Inst。，．43， T489 （1952）e
14）J・P・丁・yl…J・Text・エ・・t・・．坐・T642（1954）・
一一 43 ・一
Chapter 4． Preparatton and Characterization of Test Specimen
Twelve．kinds of test specirnen inclu6ing natural． and regenerated cellu－
losic fibers were prepared， as l isted in Table 4－1， for rneasuring the moisture
absorption and desorption isotherms at various temperatures ranginqL from IQ
to 50 OC． Two kfinds of naturai fibers？ rarnie and cotton，，were scoured in a
rather mild c’ 盾獅р奄狽奄盾氏@with，20／， aqueous solution of NaOH at llO OC for one hour，
to remain their crystal structure unchanged in the cellu］ose 1．1） The
scoured cotton was further furnished to prepare two kinds of mercerized cotton，
1 and II as listed in Table 4－1， by soaking in 180／o and 350／o aqueous solu’tions
of NaOH， respective］y， at a room temperature of aihound 20 OC for about one
day without any mechanical restr－afin to produce alkali celuloses， the so－called
Na－cell－1 and Na－ce］］一一N，2’3） leaching in running water for several day．s to
4）
remove the alkal i and to reduce the alkali cellulose to cellulose hydrates，
and drying in air and ultimately in P20s to obtain the specimens having crystal
structure of the cellulose II．1） The change in the crystal structure during
the mercerization pro・cess is illustrated in Figs． 4－1 and 4－2 in accordance
4）
to the proposal by Meyer， Misch and Badenhuizen．
Four kinds of regenerated ceHulose fibers were furn．ished from factoriesi
i．e．， a normal viscose rayon staple of 1．5 den with 2．5 cm cut， a high－tenacfity
viscose rayon filament yarn of 1，650 den with 1，100 fils， a polynosic rayon
staple of 1．5 den with 5．1 cm cut， and a cuprammonium ray6n staple of 1．5 den
with 3．8 cm cut．
Four kinds of cel lulose derivativRs are added： i．e’．， two kinds o£ acetate
rayon differing fin the degree of acetYlation， a dfi－acetate rayon filament
yarn of 75 den with 21 fils of 55．2 wt．O／o acetYlation and a tri－acetate rayon
filament year of 75 den with 20 fils of 61．6 wt．O／， ace’es／lation， both with
respect to a glucose unit； a sodium carboxy met’ ?凾戟@cellulose fabricated in
a form of nonwoven fabric frorn filment yarn of 75 den with 20 f“s of 18・3
wt．O／， Na－carboxy methylation also with respect tQ a glucose unit； and a non一
一 aA ．． 1 1
crystalline cellu］ose， not in a form of fiber but of powder， being obtained
from powdered ancl fully dried tri・一acetate by saponification in 10／o sodium
ethylate solution of anhydrous ethanol for one day at room temperature．’
Al l of these fibrous specimens， with exception of the Na－carboxy methyl
cel］ulosDe fabrict were purified by a Soxhlet extractor using a mixture of
benzene and ethanol wfith a volume ratio of 2 to 1 for the ceHulose fibe）”s
and ethyl ether for the acetate rayon fibers， respectively， in order to
remove o“ or fatty rnaterials used in spinning and／or finishing processes， if
any． The extracted fibers were leached in boiling water for a few hours，
air－dried and stored in a P20s desicator for at least a week until used as
bone－dried specirnens for the rneasurement of moistu“e absorption isotherms．
丁he bulk density of the test specimens， 1isted in Table 4－1， was dete｝＾一 n－heptane
mined by means of the density－gradient－column method of CC14／nitrobenzene Or／A
a‘L 30．0 OC after be‘，ng bone－dr‘ied in vacuum．． The degree of crys＋．aH i，niti，
Xd was determined in weight fraction from the bulk density of each specimen
p by using the following relation：
（1／P） ＝ Xd（1 ／Pcry） “ （1 一 Xd）（1／Pam） （1）
・h・・e．・，，yand・、mareth・d・・ゴrties・fthec・y・t・Hi・eand・・nc・st州e
regions in the specimen and are estimated to be 1．592 and 1．470 for the
natural cellulosic fibers having cellulose 1 type crysta15） and 1．583 and
6）
1．470 for the regenerated cellulose fibers havfing cellulose II type crystal．
Fig． 4－3（a） shows an optical ・coordinate system， O一×1’x2tx3’ fixed within
a horizontal scanning type ×一ray diffractometer in which the fincident ×一ray
beam％（i・u・it・ect・r）「…dr・t・d in a directi・n p・・a11・1 t・the xギーaxi・・
and the diffracted ×一ray beam S （in unit vector） from the （hk2）crystal planes
within the specimen placed at the original point O is detected ・by a counter
tube scannin，g within the xl’x2’ @plane （horizontal plane） as a function of
diffraction angle 2eB，j， where eB，j is the Bragg angle of the （hkk） crystal
nr 薗 峠」 一
P1・・e andエ」i・recip・。ca11・ttice vect・r・f th・（hk£）・・y・t・1 plane・F・・
a photographic niethod of m．easu“fing the ×一一ray diffraction， a flat photographic
plate may be arranged in such that the plate normal is parallel to the ×1’ L
axfis and its distance from the specimen is d．
Fig． 4－3（b） shows a geometrical relation of the optical coordinate system
of O一一×1’×2ix3’ to the specimen coordinate， system of O－xlx2x3 in CermS Of two
rotational angles of the specimen about the x3一 and xl－axes， x and S）， taking
a state of coinciding the xii－axis with the xi一一axis as original referring
state． Fig． 4－3（c） shows orientation distribution of the reciprocal lattice
vectors of nj on the surface of unit sphere fixed within the specimen，
Nj（¢1，Xgl）ol being measurable from the ×一ray diffraction intensity distribution，
Ij（x，9）x as a function of x and g ； i．e．，
Ni． （¢1 ，ilJl），b．dXYI ＝ KI．i （x，9）．dst （2）
V ’ 1 V tL
As recognized from Figs． 4－3（a） through 4－3（c）， the orientation distri－
b・ti…fth・エj vectQ…fth・（hk2）・・y・t・1 P1・nes ・ithi・th・・pec．i・…pace
can be measured by fixing the counter tube at twice the Bragg angle 2eB，」，
as shown in Fig． 4－3（a）， and rotating the specimen about its xl－axis by the
ang1・Ω・hMe keepi・g th・・th・…t・ti。nal ang1・X・b・・t it・x3－axis at
given angles （eB，j 一 〉〈o）． When fixing the x3－axis as parallel to the fiber
axis of the specimen and taking into account the cyl indrical symmetry of the
o「「entation d『st・ibution of theエ」vecto「s w「th「espect to the fiber axi・
（the x3－axis）， then the orientation distribution functiOn， Nj（¢1，XYI）ol．goO，
・hich must’ be「el・t・d to lj（X・Ω）X・θB，」・・g’・e・by Eq・（2いg・・d…ugh
t・坐・p・e・ent th・・rient・ti・・di・t曲・ti…fth・エj vect・r・f・・the cyli・d・ical
symmetric systein with respect to the x3－axis； 1’．e．， Nj・（03，Xg3）， where 03 and
Y3 are， respectively， the polar and azimuthal angles of orientation of the ．1zj
vectors with respect to the x3－axis， and Y3 is randomly dis．tributed． The
measurement@of lj（xlS2）x．eB，j at a given diffraction angle 2eB，j is the so－called
一 AA ．一 一丁）
’e 一 2e scanning’ and is valid fQr determining the cyl indrical－symmetric
ori’ ?獅狽≠狽奄盾氏@distributioh・function of the ！ij vectors， Nj．（03，Y3；random）， with
respect to the 13－axis for particular matehals having’the fiber structure．7）
When determining Nj（03，W3）， as mentioned above， any order of moment of
the uniaxial （cylindrical symmetric） orientation distribution funct．ion of
the r， vectors with respect to the fiber axis， such as the second moment， can －J 8’）
be calculated as follows：
rr／2 ．ff
2． ． of’ ［05’ Nj（03，’i’3）dxy3］¢3cos203sino3do3
＜cosΦ3＞ゴ 。／21t o」 ［！ Nj（03，w3）dNy3］¢3sinO3dO3
廿／2
．tst Nj（¢3）cos2¢3sinO3d¢3 （3）
T， ／2
0」 Nj（c＞3）sin〈p3d¢3
丁h・Hermans・・ sec・・d・rd・r・・1・・t・ti・・fact・r F2。J ca・b・d・d・ced f・・m th・
second moment ＜coSΦ3＞j as follows・8・9）
F20j＝（1／2）（3〈cos203＞j 一一 1） （4）
Figures 4－4 and 4－5 show ×一ray diffraction patterns of the test specimens
including the noncrystalline cellulose， all obtained by the photographic
method usfing flat photographic plate with camera distance of d ＝ 5．0 cm． As
can be seen in the figures， every cellulose specimen， with exception of the
noncrystalline powder specimen， exhibits the so－called fiber dtagram ranging
from highly to poorly uniaxial orientations of the ！zj vectors of diatropic
crystal planes parallel， and， consequently， of paratropic crystal planes
perpendicular to the fiber axis． Comparing the X一一ray diffraction patterns in
Figs． 4－4 and 4－5 with schematic diagrams of the paratropic’interferences，
． A7 － Tl
such as from the （IOI）， （10T）， and （002） crystal planes， in Fig． 4－6 and
the crystal structure in．Fig． 4－2， Gt fis revealed that the scoured ramie
and cotton have remaihed their original crystal structure of cellulose 1，
wh“e the mercerized cottons and regenerated cellulose fibe“s possess the
crystal structure． of cellulose II． For the other cellulosic fibers， the
・・ystal・t・・ct・・e…tb・…sid…bly・・d絹・d f・・m th・t・f the ce11“1・se lエ
as the specimens change in the order frorn Na－carboxymethyl cellulose，
di－acetate and to tri－acetate fibers． That is， the Na－c．m．c． fiber must remain
in some extent the crystal structure of cellulose II， as expected from its
×・一ray diffraction pattern in Fig． 4－4 and from，its chemical modification
process of a regenerated cellulose fiber， and the tri－acetate fiber possesses o
the crystal structure of pseudo－orthorhornbic； a：’ Q4．5， b： 11．6， c： 10’ D43 A
and pcry： 1．30， as reported by Dulmagel，O） all of these specimens having’
however relatively low degrees of crystal grfientation as well as of crys’L’a一一
11ini’・i y，．as ．listed in， ．’Table 4－1．
In practice， the photometric measurernent of ×一ray diffraction from
fibrous materials is usually performed by means of the e 一2e scanning method，
as mentioned above； that is， scanning the counter tube by the angle of 2こ口
rbtating simultaneously the specimen about the x3－axis by the angJe x（＝e），
but fixing the other rotational angle st at various values of 90 from O to 900．
The intensity distribution 1（2．e，S2）s2 must be composed of crystalline and non－
o
crystalline contributions； i．e．，
王（2elΩ）％＝1・ry（2θ・Ω）Ω。＋王・…（2θ・Ω）Ω。 （5）
and the separation of the noncrystalline contribution from the total ihtensity
distribution may be performed by a method similar to that proposed by Hermans
。t・i．！i－17）P，。，id，d th、t th，・・n。，c，y、t、m，e dlff，actう。， i，tensity di、t，蘭。n
is available from other sources， such as a direct measurement of the noncrysta－
11ine cellulose specimen， as prepared above．
L AQ 一 一 ”v －
The crystalline contribution， thus separated’， may be further separated
into those from the j：th c．rystalline planes by assuming each contr」bution to
be represented by a symmetric function of 2e， such・ as Lor・ enzian func－tion；i8）
1
icry（2e’S2）s2，＝ 奄奄QeB，．J・（S20）一潤D ￥tB，j一．2e）2 （6）
J
Where@12eB，j（S20） is the fintensity of the j－th crystalline diffraction peak，
Bj is the half一一width of the peak at half the peak intensity， and 2eB，j is
twice@the Bragg angle of the j－th crystal plane・ The conStantS 12eB，j（S？o）
and． ﾀ」can b・d・t・師ned by・・M・g th・・湘tane・u・equati・…fEq・（6）「・
combination with a trial and error method until a good agreement of the
calculated curve of lcry（2e，st）stowith the observed one is achieved．18）
The degree of crystallinity， Xx in Table 4－1， can be defined from
・Eq．（s） as fonows：i9）
×， ＝ff lc，y（2e，st）d2edst／f（ 1（2e，st）d2edg （7）
and be determined from the measurerr｝ent of the ×一ray diffraction intensity
distribution using a 1ilttle modified e ’一 20 scanning method； i．e．， scanning
the counter tube by the angle of 2e， rotating sirnultaneously the specfimen
about the ×3一一axis by the angle x（＝e）， but quickly rotating the specimen
about the xl－axis to perform the integrabion of Eq．（7） with respect to the
angle of st during the diffraction measurement．
Figures 4－7（a） and 4－7（b） show the integrated intensity dfistribution
27r6 1（2e，9）dS2， thus measured， as a function o’f 2e ranging from 5 to 450 to
cover the crystalline ditfraction at least from the （101）， （10T）， （021） and
（002） crystal planes for a series of the cellulose fibers， and Hg． 4－7（c）
shows the same results for the cellulosic fibers including the noncrystalline
’4g－
cellulose， all after the corrections by air－scattering， absorption， incoherent
scattering，20） and poiarization and Lorentz factors．2i） As can be seen in the
figures， the crystalline contribution to the total diffracted intensjty
decreases as the， specimen changes from the scoured natural cellulose fi．bers
to the regenerated ce］lulose fibers and further to the chemically modified
ceUulosic fibers， indicating a descending order in the degree of crysta－
11inity， at least qualitatively．
Figure 4－8 shows the results of quantitative separation of the crysta－
11ine and noncrystalline contributions to the total corrected diffraction to
calculate the degree of crystallinity frofn Eq．（7）， as l isted in Table 4－1，
1り2）
by a similar rnethod as proposed’by Hermans and Kieidinger for some
representative specimens； the scoured ramie， normal viscose rayon， Na－carbo－
xymethyl cellulose rayon， and noncrystalline cellulose fitself． The noncrysta一
“ine contribution in each speciTnen is assumed to be the samg in its shape
as that of the noncrystalline cellulose which has been already crystallized
in a small extent due to lapse of time for about one month after the sapo一一
22．24）
nification of tri－acetate cellulose．
円g・・e4－9 sh・ws p1・t・f th・deg・ee・f・・y・t・Mi・ity X、・thus d・t・・而・ed
’from X－b“ay diffracV’on， against the degree of crystallinity Xd， calculated
from bul k density of the specimen by using Eq．（1）． As can be seen in the
figure，’@a l inear relation holds， always giving’ ＝@l ittle larger values of × X
than Xd fo’r this particular s＞tstem of cellulosic materials not only due ．to
the choice of the value of pam in Eq．（1）， but because gf different origins
between the defined quantities of Xx and Xd． Hereafter， the values of Xx may ？；
be adoPted because of its more reliabiハty in physical definition than
that of Xd・
にn曲 JU F；
References
1）’KrH・ Meyer and L． Mfisch， Helv． Chim． Acta， ．Z．LO， 232 （1937）．
2） H． Sobue， H． Kiessig， and K． Hess， Z． Physik． Chem．， B， 43， 312 （1939）．
3） 1． Sakurada and．S． Okamura， Kolloid－Z．， 81， ；99 （1937）．
4） K．H． Meyer， L． Misch， and N．P． Badenhuizen， Helv． Chim． A6ta．， 22， 59 （1939）．
5） P．H． Geil， ”Polymer Single Cryst61s”， John IAIiley ＆ Sons， New York， 1963．
6） P．H． Hermans， ”Physics and Chemis＃ry of． CellulOse Fibres”， Elsevier，
New York， 1949．
7） H．P． Klug and L．E． Alexander， ”×・一ray Diffraction Procedures’‘， John IAIiley
and Sons， lnc．， New York， 1954．
8） S． Nomura， H． Kawai， 1． Kimura， and M． Kagiyama， J． Polym． Sci．， A－2， 8，
383 （1970）． 一 一 9） P．H． Hermans and P． Platzek， Kolloid－Z．， 88， 68 （1939）．
IO） ltJ．J． Dulmage， J． Polym． Sci．， 26， 277 （1957）．
11） P．H． Hermans and A． ltJeidinger， Text． Res． J．， 31， 558 （1961）．
12） P．H． Hermans and A． Weidinger， J． Am． Chem． Soc．， 68， 2547 （1946）．
13） N． Komatsu and A． Sakata， Kogyo Kagaku Zasshi， 61， 1626 （1959）．
14） L． Segal， J．」． Greely， A．E． Martin， Jr．， and C．M． Conrad，丁ext． Res． J．，
29， 286 （1959）．
15） V．C． Haskbll and K． Owens， Text． Res． J．， 30， 993 （1960）．
16） N．B． Pati1，’ N．E． Dweltz， and T．’qadhakrishnan， Text． Res． J．， 32， 460 （1962）．
17） J． Mann， L． Roldan－Gonzales， and H．J． IAIellard， J． Polym． ScG．， 42， 165
（196e）． ． 一18） K．． Fujino， 卜｛． Kawai， T． Oda， and H． Maeda， Proc． 4th Intern． Congr． Rheo1．，
． lnterscience， New York， 1965， Part 3i p．501．
19） IAI． Ruland， Acta CrYst．， 14， l180 （1961）．
20） P．H． Aermans and A． Weidinger’ C J． Polym． Sci．， 4， 709 （1949）．
21） P．H． Hermans and A． Weidinger， Rev． Trav． Chim．， 65， 620 （1946）．
22） M． Kimura， T． Hatakeyama， and J． Nakano， J． Appl． Polym． Sci．， ］8， 3069
（1974）． ， 一23） H． Hatakeyama， T． Hatakeyama， and J． Nakano， Appl． Polym． Symposium， No． 28， 743 （1976）．
24） H． Hatakeyama and T． Hatakeyama， Macromol． Chem．， 182， 1655 （1981）．
Specification 十Density（gr．／c．c．）
Degree of Crystallinity
Xd＃ Xx＃＃
十十Degree of Crystal Orientation
CrystalStructure
Scoured ramie
Scoured cotton
Mercerized cotton I
Mercerized cotton II
Normal viscose rayon
High－tenacity rayon
Polynosic rayon
Cuprammon ium rayon
Na－carboxymethylatedrayon
Di－acetate rayon
Tri一一acetate rayon
Noncrystallinecellulose
1．545 1
1．537 4
1．510 3
1．507 3
1．503 1
1．496 1
1．501 8
1．507 2
1．536 6
1．313 5
1．300 0
10477 4
63 （O／，）
57
37
34
31
24
30
34
7．0
55 （％）
50
39
37
34
27
40
37・
18
16
］9
11
Extremely highlyoriented
Fairly well・一〇riented
Fairly well－oriented
Fairly well一一〇，riented
We11－oriented
Highly oriented
Highly oriented
Highly oriented
Moderately oriented
Slightly oriented
Sl ightly oriented
Non－oriented
Cellulose I
Cellulose I
Celluloge II
Cellulose II
CeHulose II
Cellulose II
Ceilulose II
Cellulose II
Cellulose II（possibly）
Pseudo－Ortho（possibly）
Psedo－Ortho
None
十μ＃
＃十
μ＃十
determined by a density gradient column meth．od of CCI4／nitrobenzene or n－heptane at 30．0 ± O・1 OC・
determined from bulk density of specimen．
determined from ×一ray diffraction intensity distribution．
qualitative estimation from paratropic interferences in ×一ray diffraction pattern．
刀一
（ 一
＿ 1つ ＿ ㌔ノ」．
Captions for Figur．els
Fif．． 4－1． Dfiagram of the positions of the atoms in the elementary cell of
native cellulose （cellulose 1） after Meyer and Misch．
Fig． 4－2． Crystal modifications of native cellulose during mercerization
process after Meyer， Mischl and Bandenhuizen．
Fig． 4－3． Schematic diagrams showing （a） the optjcal coordinate system，
0－xギx21x3焔xed・ithi・ah・ri・。・t・1・canni・g typ・X－ray d「ff・ac餉
tometer； （b） a geomerical re］ation of the optica］ coordinate system
O－xギx2】x31 t・th・・pec「men cQ・rdinat・・y・t・m・f O－xl・2・3；（・）
orienta’tion distribution of the reciprocal lattice vectors of Lj
on the surface of unit sphere fixed within the specimen．
Fig． 4・一4． ×一ray dfiffraction patterns froni natural cellulose fibers； scoured
ramie， scoured cotton， and mercerized cottons with 180／， and 350／，
NaOH， a Na－carboxy methyl cellulose fiber， and a noncrystalline
cellulose powder． Fiber axis is vertical with camera dGstance of
5．0 cm．
Fig． 4－5． ×一ray diffraction patterns from regenerated cellulose fibers； normal
viscose rayon， cuprammonium rayon， hig’h一一tenaciry rayon， and polynosic
rayon， and two types of acetate rayon； di－acetate and tri－acetate
rayons． Ffiber axfis is vertical with camera distance of 5．0 cm．
Fig． 4－6． Diagrams and photometric curves of the paratroric interferences
（equator） of （a） nativ’e cellulose with cellulose 1 crystal and
（b） regenerated celluloSe with cellulose II crystal after Schramek．
Ffig・4－7・Ase「ies of photomet「ic ×一「a 凵@diff「action cu・ve・f・。m剛「a1・
regenerated， and’modified cellulosic fibers， taken by rotating
Fig． 4一一8．
Fig． 4－9．
一53－
quickly the spdcimen about the x］一axis and corrected by air－scattering，
absorption， incoherent sca．ttering， and polarfization and Lorenz factors，
一to evaluate the degree of crystallinity from Eq．（7）．
Results of quantitabive separation of the crystaVine and noncrysta－
lline contributions to the total corrected diffraction to calculatb
the degree of crystallinity for some representative specimens； （a）
scoured ramie， （b） normal viscose rayon，（c） Na－carboxymethyl
cellulose fiber， and （d） noncrystalline cellulose．
Degree of獅モ窒凾唐狽≠撃撃奄獅奄狽凵C Xx， plotted against degree of crystallinity
Xd， at 300c．
一一 54 一一
稜1しψ
賊8、Q
へ
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A ’、 ’
x 二
’4
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Fig． 4－1．
n
，C一
糖
σ一一一伽
Cellulose I o
a ＝ 8．35 A，
B ＝ 840
（native）
o
c＝ 7．9 A
Cel］u］ose 工1 （hydrate）
o
a ＝ 8．14 A，
B ＝ 620
C
o
一 9．14 A
，
㎝㎝
蓼
Alkali cellulose 1 o
a ＝ 12．8 A，
oB一 40
o
c ＝ ］3．2 A
Cellulose hydrate o
a ＝ 10．0 A，
B ＝ 520
C
o
＝ 9．8 A
Fig． 4－2一．
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Fig’ D 4－6
一 60 ・…
影聾
霧
8
b
e
｛oo2｝
／一一一一
Scoured・Ramie
O喀
E
［ 呂
。
（101）
’一一一mt
e
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：’e7 e n
o
．
一 一
．
．
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s 一
一 一．
．
一 一
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一一
．
一 t 一i 一
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oo
o
5 10 15 20 2S 30 3S 40 45
雷
Oり
O貯
P門⊆コ
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〇四
。
． Scoured Cotton
．
e．
o
o
ee 督
．
．“
oe 9
o
．
o
．
．
・
．
．
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．
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．
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．
．
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一 一．
i 一
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診5⊆9ξ
8
8
禦
5 10 15 20
（10T）（oo2）
＝’e7 ． ．
t
・
25 30 35’ 40
Mercerized Cotton 1
45
⊆O『ρO邸」↑↑r自
紀
。
一 一
e
．
e
（101）
フ 一 e
e oe
oe
．
e．
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．
’
・
．
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e
一 一．
“ 一
e 一
i 一 一
．
e e
s 10 IS 20 25 30 35 40 45
8’
Oロ
O噂
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o
Merceri’zed’Cotton ll
e一
e
． ．
e．
o
一 〇 e e Oo
一 一
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．
．
一 s
e
り
● ，
・
一 一 〇 〇 e
e ’ e
一 q
“
eo
ee
＃
5 10 15 20 25 30 35 40 45
Twice thd Bragg angle， 2e （ O）Fig． 4・一7（a）．
一61 ’冒．．
爵 i1
8
O貯
L．
NQrmal ．Viscoge Ra’ 凾盾氏D
1
Cl（汗》COO2）
T・ ・． 7 ．
e
．
i鵠
a
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e eo
．
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．
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oo
e
e5 IO IS 20 25 30 35 40 45
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e
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e
Cuprammon ium Rayon
o’
翼⊆5
8
p
．
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e
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e
e
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e
oe
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ワ
o o
8
5 10 15 20 25 30 35 40
High一一tenacity Rayon
45
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＄
＄
£
oe
．o
eb
e
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一〇7 e
（101）
．
フ ．。o e “ oe
e e
e
e
e e e ；
．
e ． ． e － h o
i e eO e o o
ee o
5 10 15 20 25 30 35 4e 45
Oo◎
O胆
O噌
9
e
Polynosic Rayon
ee
“
e
e
．
e
e d
O ． e
o
o
”
．
一 ・ 一
e b
・
．
．
一 “
“
e o．
o 口 o e oe
e ・e
．e
oe
5 10 15 20 25 30 3b 40 45
Twice the Bragg angl e， 2e （ O）Fig； 4－7（b）．
ダロー o乙 一
調陣卜
霧
Na7carboxymethylated Rayon
Oゆ
O雪
瀦
o
e
．
一 e
“
e
g
ee
e e o D
eo
e
e
ee e
－ o．
t t o 一 一 一 e e t t e
e e e
o
o
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一65一
Chapter 5． ’ dxperimental Results and Di・scussion
1［bgE［pgg￥ng［glgE－gfLlytgi．E1y－r．e：EiigEo－tp！Jgn／ 一． 一 ’’’’”．
shorterl） has ap’pl ie’d thermodynathical reasoning to t’he problem oi the
absorption of moisture by textile materials， making use of the Kirchoff
equation for the heat of’ р堰nusion of a，solution．． This is derived from the
welT－known Clausius－Clapeyron equation and can be appl ied to any two－phase
system in which matter is transferred from one phase to the other by a
reversible process．
Shorter’s derived equation for the absorption of moisture by a textile
material is
QL一（B奄si＝gilrn－n2 ddTin h），， a）
where QL i’s the differenbial heat of absorption of l iqufid water by the textile
material at moisture regain or at the absolute temperatu“e T in equilibrium
with the relative humidity h， R is the gas constant， and M is the molecular
weight of water．
Equation （1） may be rewritten as fo］lows：
QL 一 一 一li一 一g－i（一ll－lil fll ！Tl） （2）
Thus， if a moisture regain ot is maintained by a relative humidity hl
at an absolute temperature Tl， and by a relative hurnidity h2 at a temperature
T2・Eq・（2）9「ve・・by the sub・tit・ti・・。f f禰t・f・・1・舗t・・r・・1 inc・ement・，
RT1丁2（1・h2－1・h1） QL ＝ （3）
M （T2－Tl）
Hence， from a knowledge of the variation of （ln h） with 1／T for a given
一一 AA 一一
moisture regafin， the value of一 QL may 一be calculated by’means－ol’@Eq．一（3）． Such
absorption data for a soda－bo“ed cotton’a－t／．various ．temper．atures have－been
first given by Urquhart and Williams，2） as shown in Ffig． 5一一1．
F・・Eq・（3）t。 b・・t・「・tly valrd・QL・h・ul・d・・t va・y．b・tween th・t・mp・・a加・e・
Tl and T2， and the absorption process should be reversible．一That the process
is not reversible fis shown by the familiar hysteresis eftect， as wiH be
discussed in the following section in this chapter， and it is a debatable
point as to which values of moisture regain ought to be used in the calculation．
However， Eq．（．3） has been appl ied widely to calculate values of QL from
3一 6）
absorption data．
It is interesting from the theoretical viewpoint to compare the heat and
the free energy of absorption of moisture by textile materials． ln this
connection， the Gibbs－Helmhortz equation ynay be applied to relate the changes
in the total （or internal） energy， in the work content （or free energy） and
in the un．avai’lable energy （entropy） in the system．
For the absorption process， we have the Gibbs－Helmhortz equation
AG ＝ QL 一 TZNS （4）where AG i s the Etets！zs｝i12gcrease i n free energy， QL i s the heat of absorption l ost
by the system， and AS is the decrease in entropy， when 1 gram of l iquid
water is absorbed by an infinite mass of the textile material pOssessing a
mofisture regain of oc at the abso］ute temperature T．
The decrease in free energy per gram of l iquid water absorbed is given
AG＝“T ln（p，／p）’ （6）
where p is the equil ibrium water－vapour pressure of the partially saturated
textile material of regain ct at the absolute temperature T， ps the saturation
一67一
vapour pressure at． that temperature， a 垂пEthus p／ps．is the relative humldity
at the．tempr「atu「e T w’th．whiごh the system ’r．．1n egu’1帥m・ 』
T・bl・5－1・h・wS・脚・と・t・l d・t・・f th・m・i・P・・e ab・・rpti・hう・dth・・m・
of norma］ viscose rayon， dried in vacuum at 30 OC and measured at various
tr叩・脚er囎・g f…1・t・5・oC・Fig・・e・5－2 and 5－3・・e th・・6suit・・f
replotti’獅〟@the data of moisture regains as function of relative humidity and
partial vapour presSure， respectively． As can be seen in the figures， the
higher the temperature， the specimen absorbs less amount of water fin equili－
brium at any relative humidity or partial yapour pressure． This is because all
textiles in taking up moisture to release heat， and it fo］lows as a thermodynamic
necessity that the amount of water taken up at constant relative humidity must
decrease with increasing temperature．
In Fig． 5一一4， the ’free energy calcu］ated from Eq．（6）， and the differential
heat of absorption of liquid water also ca］culated by using Eq．（2） from the
experimenta］ results in Figs． 5－1 and 5一一3 for the soda－boiled cotton and the
normal viscose rayon， respectively， as we］1 as from those by Jeffries6） for
a hlgh－tenaCity二rayon，are plotted agains・し relative humidity． In the figure，
the sol id l ine for thel differential heat of absorption QL i’s derived by Rees7）
combining his own results8） with those by Guthrie9） for eighteen kinds Qf
cellulose fibers． Although the experimenta］ results deviate considerably
from’the sol id l ine of QL， general dendency is fairly identical to・indicate
that the decrease in heat content （QL） of the ceHulose－water system is greater
than the decrease in free energy （AG）． By reference tp Eq．（4）， it shows that
the absorption of water by cellulose is accompanied by a decrease in the entropy，
or unava“able energy， of the system． The d，i．fference between the heat and the
free－energy terms represents an excess enerqLy which shows by how much the energy
of binding of the wather molecule to the cellulose surface exceeds the energy
of attraction between a water mo3ecule and a free water surface． 丁his excess
一68一
energy， calculated frorn the solfid curves in Fig． 5－4s’ 奄刀@shown graphically
in Fig． 5一・5． The curve relating enticopy decrease and ．relative hurnidity is
id’ ?獅狽奄モ≠戟@in shape to th’ ?@excess energy curve，’ rince， by Eq．（4），．AS ＝
excess energy／T． The values of the decrease in entropy are shown on the righ’し一
hand ordinate of Fig． 5－5．
The following deductions may be made from Fig． 5－5：
（1） The excess energy is greatest at the lower values of relative humidity；
therefore， water molecules are most strongly attracted at low vapour
pressures． The first molecules are absorbed on sites where the attractive
force is greatest and， as more molecules are attracted， the attractive
force decreases， due to the water mo］ecules exerting a repulsive force
on one anQther， or to forrnation of multi－layers of molecules．
（2） The water initially absorbed at a low re］ative humidity has an excess
enerq．．y of ca．IOO cal／g which is roughly equal to the ］atent heat of
fusion of icG， indicating that the first water molecules absorbed have
degrees of orientatfion and association comparable to those of ice．
（3） The curve flattens out at intermediate values of relative humfidity
with a rapid drop above a relative humidity of 800／o due to the change
possibly to capillary condensation corresponding to the steep part
of the absorption isotherm． The flat portion of the curve indicates
that， but for capi］lary absorption， there would be an energy excess of
absorbed over free water even up to saturation． As long as absorption
is molecular rather than capillary， it may be assumed that there is an
entr．opy difference between the absorbed and the l iquid states．
（4） Even near saturation， there appears to be a finite excess energy of
’1 O）
absorbed over free water． Wahba suggests that this indicates that the
absorbed 11quid near saturation may still be d．ifferent from bulk l iquid，
possibly due to some change in the properties of the l iquid when present
一69一
in fine capillaries．
（5） The decrease in entropy is greatest at． low values of ’relative ’hurnidity．
The results of Rees．and Guthrie yield a vaiue of O．29 cal／g／OK near
dryness， which is in good agreement with the v，alue of O．28 obtained by
Babbi．tt．叫r。。 d、t、。， c。tt。， a，d w。。d cell、1。、e．
APsgtR11丁目－gn9．P§Egr21ユgn－ti￥E1eEe§ユE
Table 5・一2 shows moisture absorption isotherrn at 30 OC for norrnal viscose
rayon dried in vacuum at 30 OC， and its subsequent desorption isotherm from
saturation regain also at 30 OC， both measured by the weighing bottle method．
Figure 5－6 is replots from the results in Table 5－2， demonstrating obviously
the so－called so．rption hysteresis phenomenon that the absorption and desorption
isotherms do not cpincide with each other to leave considerable divergence
between the two yalues of the regain at a given relative humidity．
At first it was thought that this phenomenori．， to which the name hysteresis
has been given， was due to a very slow atta「nment of equilibrium， and ’しhat
absorption and desorption values would be fidentical if sufficient time were
allowed for the true equi］ibrium to be reached． There is arnp］e evidence now，
however，’@that the different values do， in fact， represent true equilibria．
For example，’ samples brought from opposite directions into an atmosphere of
medium humidity rdached their different absorption and desorption equ“ibrium
values i’n a few wgeks； they were then allowed to remain in that atmosphere
for over three years， and at the end of that time their regains were as far
12）
apart as they were at the beginning．
So far only the extreme variations that result from startfing in a completely
dry atmosphere’@on the one hand and a saturation atmosphere on the other
have been considered． pioneering experiments by urquhart and Eckersan13）
have shown that， where the differences of prehistory are less extreme， points
between the absorption and desorption curves are obtained． It is apparent that
一70－
any．point between the two extreme curves may， u．ndeic appropriate condi．tions
of． htimidity and prehl’story， represent． the regain of・ a sample ・ip－question・，．
and hence that the specification of humidi．ty ．and tempera，ture does hot u’ni－
quely define the amount of wate“ in the fiber， but only the l imits between
．which that amount shall l ie． ln other words， the two curves do not form an
equilibrium ］ocus but define an equilibrium area， and it is therefore important
that these extreme curves should themselves be specified with some accuracy．
At this stage it is desirable to see fif these observations okC sorption
hysteresis can be fitted into a reasonable explanatry scheme． It is clear that
the molecules of mgst textile fibers contain hydrophHic groups to which water
molecules can be bound by means ofJhlMg！zggg［！d b d ， and it is also explafined
th，at in the more crystalline regions of the fiber the molecules are held toge－
ther lateral ly by hydrogen bonds between such groups on adjacent molecules． A
certain amount of this kind of cross一一linking wiH occur in the amorphous regions
、1、。，P・・t翻a・ly・t th・楠g…fth・ c・y・t・1］i・e p・rti・ns．1・the ce11・1・・r・
fibers， with which we are mainly concerned here， the pricipal hydrophilic groups
are the－nh Lgcg2syjd 3 u s of the cellulose molecules， though no doubt the other
oxygen－containing groups p］ay a smaller part． This is clear enough from the
fact that the hygroscop fi eity of cellulose うs reduced， bu’し not to zero， when
all the hyrdoxyl groups are removed by the formation of appropriate tri－
substi’しuted derivatives． In other words， the sorp’し「on hysteresis may be
explained in terms of the dual functionality of the hydroxyl group， bonding
with each other by hydrogen－bonds to reject the bonding with water molecules；
and vice versa．
Two addibional experimental observations are of value fin constructing
the theoretical framework along with the above exp］anation about the sorption
hysteresis． Table 5－3 and Fig． 5－7 show the moisture absorption isotherms at
30 OC for a sample of the normal viscose rayon dried in vacuum for a day at
＿ 71 一 ’ 国
different elevated temperatures，一 60， 90 and 120 ．Oe，・．in一・．comparison with the
・esult・rn丁・ble．． T－2 f・r 一th・．．…e．sampl． 秩E．b・t・．d・ied i・． vac岬t 3…oc・．A・．
can be seen in the figu“e， the higher the drying temperature， its hygrosco’ 吹f奄bity
is definite］y reduced， as has been investigated by Urquhart 6“d Williams for
a cotton sample，14） with exception of the results at high humidfities near
saturation at which the data are considerably scattered due to less reproduction
unless ’しhe measurうng temperature 「s strictly controlled at a given temperature．
On the other hand， if it is similarly heated in the presence of a high concen－
tration of water vapour， its hygroscopicfity may be expected to increase， as
15） for a，cotton samp］e． Table 5－4 andhas been demonstrated also by Urquhart
Fig． 5－8 show the moistur desorption isotherrns at 30 OC for the normal viscose
rayon soaked in hot water at different temperatures， 60 and ’ X0 OC and ’モ盾獅р奄狽奄盾獅?
under goo／， relative humidity at 30 OC． When compared wfith the results of’ @．，
desorption isotherm うn 丁able 5－2， it is seen that the higher the treating
temperature ，at saturation regain， its hygrogcopicity fis increased， again with
exception of the results at high humidities near saturation at which the data
are somewhat scattered to deduce the above conclusion．
It may be assumed for the present that the prjmary cause of the taking
up’of water is， as mentioned above， the hydrogen－bonding of water molecules
to free hydroxyl groups in the cellulose， though there is l ittle doubt that
this Simple explanation is compl icated by secondary effects． The molecules of
cellulose， and， of course， the hydrophilic groups， are in a state of thermal
vibration that will increase with increasfing temperature； thfi＄ can result in
both the making and the breaking of cross－linking bonds， and the final effect
will depend on the amount of water present． Where the amount of water is high，
most of the free hydroxyl groups on the cellulose wiV have water molecules
attached to them， and hence the tenddncy for further cross－linking to occur
by mutual satisfaction of hydrooxyl groups on adjacent cellulose molecules
一一 72 一
will’be negl igiPle； on the other hand， the breakin．g of ．alread￥ 一existing links，，
whigh． bec’ause of’ xhe inc．reasing vibr．at」on ，w“1’occu．r． 一more 一rea・d“y a．t一 ，hi．gh ．．．．
temperatures， may ’ ?≠刀f奄撃凵@result in both the groups concdrned remaing free，
since water molecules will probably attach themselves before recombination
becomes possible． The fin’ ≠戟@result is obvious］y a more－or－less permanent
increase in the number of free hydroxyl groups， and hence in the subsequent
hydroscopicity of the materlal． But， if the amount of water present is srnall，
the tendency for additiona］ free groups to be formed will be more than counter－
ba－lanceed by the tendency for exsisting free groups to combine with one another，
since few oS them will have attached water mo］ecules to prevent this occuring．
The fina］ result is therefore a permanent decrease of hygroscopicity．
Now consider the removal of water from a sample of Wet fiber 一 preferably
removal ekfected by putting the sample into a dry atmosphere at room tenipera－
ture． lnitially， all the available hydroxyl groups will have water mo］ecules
attached to them， but as the fibbr d“ies the’se groups wiH be free， and
there w“1 be a tendency for their residual valencies to be mutuaHy satisfied
by hyrdogen bonding， involvfing a certain amount of realigment of the cellulose
molecules． This process will go on with increasing difficulty， because of
the decrease of ’ 唐翌?nling a’ 氏f
п@co’nsequent greater difficulty of realigning the
molecu］es， unti］ all the water is removed， and in the process fit is to be
expected tha’煤@strains wiH have been produced in the fiber． The belief that
there is a tendency for change of configuration to occur does not， however，
involve the assumption that it always will occur； some molecules wiH be held
more readily than others？ and it may be that a change of configuration is
possible only when a loosely bound molecules attains momentarily a sufficfiently
large ampl itude of vibration， so that even the dry material rnay contain an
appreciable number of free hydroxyl groups．
エf this m・t・ri・1 i・・…11…dt・ab…b・・ter， the ab・。，pt寸。，而1
．． 7Q 一．．
i J
occur fin the first instance on these o．roups． that remain， but一 the number of
勺脚・．av・il・b1・f・r・b…pt雪・師m・c・e・・e・・ab・。・pti・n p・・ce・d・・．s「nce．．
a proportion of the groups freed by therma］ vibration will be prevented
from reforming cross－linkages by the speedy attachment to them of water
molecu］es． The number of active gro．ups available during absorption will at
any given stage tend to be less than during desorption， because the amplitude
of vibration of a molecule held to another by the attraction of one or more
acti’ve groups will be less than that of a molecule with the active groups
free． There is he’ 窒?C therefDre， an explanation of hysteresis which postulates
that during desorption and absorption the number of active groups concerned
in the absbrption of water decreases and increases respectively， but with a
lag during absorption， so that for the same number of available active groups
the humidity will be greater during aPsorption than during desorption．
This picture provides a reasonable explanation of the eFfects that
have been observed and gives a conclusion that the moisture sorption hys－
teresis is an unique behav・ior of the material， not apparent one in non一一
equilibrium， rnafinly caused by a dual functiona“ty of the hydroxyl groups
bonding wfith each other by hydrogen－bonds， preferentiaUy， rather than with
water molecules under dry atmoshere in diiute concentration of water vapour，
and vice versa under wet atmosphere in saturated concentration of water
vapour． Some quantitaive analysis ot the sorption hystereSis will be
perforrned in the following section in terms of the parameters in the BET
mu］tilayer adsorption theory．
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Table’5－5 shows the moisture absorption isotherms at 30 OC observed
mostly bt the weighing bottle method for four kinds of natural cellulose
fibers， scoured ramle， scoured cotton， and further mercerized c6ttons fin
一 7a －
t．。diff・rent ext・・ts， all d・i・d i・． vacuu・・t 300C．1・．日9．5－9・・e sh・w，
the results plotted as a function of relative h’umidity．一 A．slcan be seen in
the figure， the mois’@ture absorption behavior is quite’gl’m’i16r to each other
for these particular specimens of scoured ramie and cotton， and the hygro－
scopicity of the． scoured cotton increases with progress of the thercerization
process in associati．on with the decrease in the degree of crystallinity， as
lis・ted in Table 4－1．
Table 5－6 shows again the moisture absorpt’ion isotherms at 30 OC， observed
by the weighing bottle method， for four kinds of regenerated cellulose fiber，
normal viscose’@rayon， high一一tenacity rayon， cuprammonium rayon， and polynosic
rayon’ C a］1 dried in vacuum a，t 30 OC． The results are plotted in Fig． 5－10
as a function of re］ative humidity． As can be’ @seen in the figure， the hYgro－
scopieity increases in some extent in a good correlation wi’th the decrease
in the degree of crystaHinity determined from the ×一一ray diffraction， Xx，
rather than that from the bulk densit＞t， Xd， as l isted in Table 4一一1．
Table 5一一7 shows the moisture absorption isotherms of three kinds of
cellulose derivative fiber， dried in vacuum at 30 OC and measured at 30 OC
by thb wefighing bottle method and the sorption balance method， as well． Two
of the three cellulose deriVative fibers are a di一 and a tri－acetate fibers
wtth 55．2 and 61’．6 wt．O／， acetylations， respectively， and the other one is a
cuprammonium rayon substituted with 18．3 wt．O／o sodium carboxy methylation，
all wfith respect to a glucose unit， so that five－si’xth and six－sixth of the
hydroxyl groups in the cellobiose unit are replaced by the acetyl groups for
the acetate fibers， and one－ninth of the OH groups are replaced by the Na－
carboxy methyl groups for the Na一一C￥C fiber， in average． The results are plotted
in Fig’ D 5・一11’@as a function of relative humidity in comparfison with that of the
norinal vi’sc’ ose rayon． lt is seen in the figure that the substitution of the
hydroxyl groups tb the acetyl groups reducdsthe hygroscopicity of the normal
一 7一 ’
・う・c・・e・ay・・in 9・e・t ext・・t・・h・re・・th・t t・．thr r・d坤．．ca・b。・y・・thyl
groups increasies the hygroscopicity， gonside．rably． S，im．ila－r’kin’d－of ex，pe．’r’irden．ts
was carried out by the sorption balance method－at 30 OC， a’s shown in Table
5－8， for a series of cellulose acetate f“ms， not of fibers， differing in
degree of acetylation from 44．7 to 61．6 wt．O／， with respect to a glucose unit，
i．．e．， four一一sixth， f．ive－sixth， and six一一sixth of the hydroxyl groups in a
cellobiose unit are replaced by the acetyl－groups． The results are plotted
in Fig． 5－12， again in comparison with the absorption fisotherm of the normai
viseose rdyon at 30 Oc． As can be seen fin the figure， the hygroscopicity of
the normal viscose rayon decreases with increase in the degree of acetylation
to change’@the system from hydrgphilic to hydrophobic．
Now， let us analyse the above results of moisture sorption isotherms
for ’狽??@ceTlulosic fibers and fi］rns in terms of the theories of BET multi－
layer adsorption and of Hillis thermodynamic approach． As recognized frbm
Eq．（14） in Chapter 2， the equa：tion can be put in th，e foUowi；9 l inearforini
k／／IS／p）”“t ＋一1’i（pip，） （7）
andbゾp1・tti・g（P／P、）／・〔1一一一（P／P、）〕・g・う・・t（P／P、），・mandC・・y．b・d・t・r－
mined from the slope and intercept．
The l inear relationship given by Eq．（7）， is usually found ’for the sorp－
tion data of textile fibers as well as several kinds of protein at lower
4 ，1 6－20） Fig． 5－13 demonstrateshumidities than around 500／o relative humidfity．
the situation for the absorption and desorption hysteresis data in Ffig． 5－6
for the normal viscose rayon at 30 OC． Tables 5－9 and 5－10 show the values of
vh． and C， thus determined， not only for the hysteresis data but also for the m
data in Figs． 5－7 and 5－8 to examine the effects of drying and water－soaking
temperatures upon the absorption and desorption isotherms of the material，
7C 一 IU ’“
and， subsequently， to explain the hysteresis phenomenon i’n一 terms．of the－dual．．．
functionality． of the hydroxyl groups ’in．．the cellulose molecules，
As “ecognized from Table 5－9， the desorption isotherm gives larger’
values of vm and C than those of the absorption i’sotherm， resulting in the
absorption and desorption hysteresis． Judging from the physico－chemical
meanings of these parameters，．as discussed in Chapter 2， it is apparent
that the wateyi accessibility becomes larger during the desorption process
than that during the absorption process even for a given material． As
further recognized from Tabl e 5－10， the effect of drying temperature upon
the absorption isotherm is clearly seen in terrns of the decrease in the
values of vm and escepially of C ， as compared with those in Table 5－9， to
make the material less water accessible． The situation is just opposite to
the effect of water一一soaking temperature upon the desorption isotherm，
in№窒?≠唐奄獅〟Cthe values of vm and C， especia．11y of C， and mak」ng the materfial
more water accessiblet The chqnge in the value of C， the bonding energy
characteristics betwedn water－molecules and water accesible sites in the
abs’盾窒b?獅煤C must be understood in terms of the change in degree of hydration
of the hydroxyl grouPs due to their dual functionality； yieldi’nq． many desrees
・f．hyd・ati・n dbp・・di・g・・th・d・y内and・・t・r－s・aki・g tempera加・e・・
Figure 5－14 shows， as an example， comparison of the moisture absorption
isotherm of normal viscose rayon at 30 OC with that calculated from BET
equations， Eqs．（14） and （15） in Chapter 2 for infinite and finite numbers
of molecular layers， by fixing the values of C and vm， as determined above，
at 14R and O．0582， and varying the number of layers n from unity to infinfite．
As 6an’ be seen in the figure， the calculated result with n ＝ 1； i．e．，
Langmuir’s mono－layer adsorption， fits with the experimental result only
in the ve’ry dry ’state of icelative humidities less than a few O／o and， conseq－
ently， of inoisture regains less than al so．a fbw O／o， whereas the calculated
resUlt with n ＝ oo fits wi’th the expe’rimental result in a humidity range
一T T一 ノ1 一
up to ab №浮煤@40e／， beyond wh．ich it inf reases much more rapidl．y． than ’the exper，i．
mental result． Among t！e two extremes with．n ＝ 1 and oo， therefgre．．．there’．
is a calcul・t・d・esu］t・ith・max「脚numb…f・・、 d・・igh・t・d as nmax・
with which the calcu］ated result is the closest but never exceeds the
experimental result， such一 as the calcul－ated result with n ＝ 6 in the figure，
even in fintermediate range of rela xive humidity． Further， we．can define three
kinds of moisture regain at a given relative humidity； with n ＝ 1 due to
Langmuir’s monolayer adsorption， with nmax 1 n 〉 1 due to mulbilayer adsorption，
and n 〉 nmax possibly due to restrained multilayer adsorption and／or capilary
condensation．
Table 5一一11 l ists the BET parameters thus analyzed from the moisture
apsorption isotfierms of cellulosfic fibers and films at 30 OC in Figs． 5・一9
through 5－12， together with the degree of ×一ray crystallinity Xx in Table 4－1．
The values of vm and C seem to be C reasonable in comparison with ］iteratured
4，16・一20）
ones for several kinds of natural and synthesic polymers， though
the valueg have been relativGly few for the ceHulosic materials despite of
their numerous investigations of the sorption isotherm． ト
First of all， it must be pointed out that the nmax is found to be 6 for
almost every specimen with a few exceptions of 7 for Na－carboxy methylated
rayon and of 4 for tri－acetate rayon． 工rrespective of many k『nds of cellulos「c
fiber， the constancy in the ’ 獅浮高b?秩@of multilayers with a values as large as
6 is surprising， and is difficult to understand without accounting any
long－range order between the absorbdnt and absorbate； i．e．， some ordered
structure for the adsorbed waters with n ．．． ）一 n 〉 1． max
As has been diScussed in Chapter 2， the BET equations， Eqs．（14） and （15）
in Chapter 2， are essentiaMy the same， respectively， as the Hill s equatibn，
Eq．（32） in chapter 2， and Dble’s equation21） both basing on thermodynamic
apProaches． 丁hと DoleIs 6quat’ion うs
一 7R ．一 I W
A／B一一一一一：一一一一一一一一一一・一一 一 （8） 〈y ＋ x ＋ x2 ’＋ 一一一一一一一一一 一一一一一一一一一一一 ＋ xn＞
where n is the maximum number oF water molecules allowed to form a water
cluster and × is the relative hurnidi’ty． Eq．（8） is identical with the BET
equatfio’ 氏@for adsorption restricted to n layers． There is， however， no need
to assume any layer－l ike adsorption， and the same result can be obtained if
all the adsorbed molecules have fixed positions relative to one another． lt
sholud be noted that， although the maximum number of water molecules per
cluster is as large as 6， a cluster of this magnitude is not necessarily
peculiar， but occurs rather frequently； on the average there will be about
four water molecules per cluster at saturation， in common．
Figure 5－15 shows the relations of the mofisture regains with n ＝ 1
and nmax l n ＞1 for all of the ceHulosic specimens at 30 OC and 900／， rela一一
tive humidit」Nt， plotted against the value of vm． As recognized from the
figure， linear relationship passing through the original point can be
widely achfieved with exceptions of tri一 and 2．5－acetates for the forner
relation and of tri一一acetate for the latter relation． The l inear relation－
ship may be easily understood， providing that the BET equation， Eq．（15） in
Chapter 2， can be simply written as vn ＝ vmfn（C，n，x）， and that a constancy
of the function， fn（C，n，x） is widely held for the ceHulosic specimens
with excepticns of the tri一 and 2．5－acetates． Physico－chemical meaning of
val idating the constancy of the function， fn（C，n，x） must be discussed
elsewhere．
Figure 5－16 shows the plots of v against the degree of noncrysta－ m
llinity （1 一 Xx）． As can be seen in the figure， the plots can be classified
into three different Hnear relations for regenerated cellulose fibers，
natural cellulose fibers， and acetate fibers with different slopes． That
4（1 ＋ 2x ＋ 3x2 ＋ 一一一一一一一一一b一．一．．一一 ＋ nxnrl）
の 一 ／ゾ 一
i…m一・］i・ed by（1－X、）deとrease・i・th6・・d・・．rf d・・cend内・・t・・
ac．cessibili’ty of the．．rpecう艶．ns・possi『1γ．．va］i⑳持r．丁℃he．conlce’pt一．．of．”o「mali－
zati・・。f・m・n th・b・・fi・th・t th・m・i・毛U・e・b・pti・n i・m。蜘・fF・・t・’d．by
the differe・ces「n chemical and physical st・yct・・es甫・the n・nc・ysta1］ine
「egion of the mate「ia1S・Actuallyl when p。1tting the moistu「e「egain with
n ＝ 1 （Langmuiγ」s monolayer adsorption） at 90％ relat「ve humidity against
th…malized・m・as illu・trated i・臼9・5－17・there f。・・d a si・gle c・・ved
relation， 「n contrast to the l inear relation in Fig． 5－15， for a1］ of the
cellulos「c specimens． The single curved y’elation increases its slope with
increasing water accessibility of the spec「men； i．e．， the slope in the
vicinity around the plots for acetate f「beγ・s．be『ng about one－third to that
for regenerated cellulose fibers including the Na－ca rb oxy methylated rayon．
This means that the monolayer water adsorbabi1「ty is much different between
the three gγ’oups of the cellulosう。 fibers． Judging from the definition of
・m… gi・e・by Eq・・（7）and（9）in Ch・pt・・2・th・di・t・ib・tう・n dens枕y・f
・・t・・accessibl・・it・・p…nit・・ea・f A。l i・ab・・t th・ee伽・・larg・・
for the regenerated cellulose f「bers than for the acetate fibers． Detaうled
stud『es taking into account the m「crostructure of cellulose chaうn， espe－
cially the ’Functional ity o’f each hydroxy1 9roup．in glu（lose unit，）a n’ d．．its
sub、tit、t，、。ith hyd，。ph。bう、。， hyd，。ph’ilic gic。Up，2㍗24）．．、，t．be carrう，d
out．
F「guγしe 5－18 shows plots of C， bonding energy characterうstics between
the adsorbent and water molecules， against the number of hydroxyl groups
per ce］10biose unit for all of the specimens． As can be seen， there is
roughly a linear relation， though diversing considerab］y． It is in’しeresting
to note that the l inear relation g『ves a finite value of C at zero number
of hyd「・xy］9「oups fo「t酉騨acetate specimen・・Mo「e deta「1ed．studies taking
i・t・acc・u・t the functi。nality of each hy・d・xyl grQup・a・men．tioned ab・ve・
must be hoped in near future． When plotting the value of C against
一go －
the normalized vm， as illustrated in ．Fig． 5－19， there is hardly any quan－
titative correla，tion， but j’ust a tendenc’凵@that ．the larger the一 value of ．C，
the normalized vm’ b?モ盾高?刀Dlarger．
Structural Characterization of Adsorbed Water by Means of Differential
§⊆皇ζ］ロユng＿⊆色lgrユ聖臼gry．
There have been several studies to characterize the adsorbed water
in polymeric materials by means of current molecular spectroscopies， mostly
infrared and nuclear magnetic resonance spectroscopies，26－39） and micro－
40一 49） Let us refer a recent study bY Nakamura， Hatakeyama， andcalorimery．
Hatakeyama on the bound water of cellulose by differential scanning calori－metri8gnd discuss the nature and， consequentiY， the structure of adsorbed
water in ceHul．osic material in relation to the BET analyses of adsorption
isotherms in’@the previous section．
Figure 5一一20 shows a schematic DSC curves of cool ing and heating of water
adsorbed on cellulose materials． When a specimen containing water is cooled
f・・m・…t・叩erat・・e t・200。K， th・飾st一・・d・．・tra・siti…fw・terう・n・t
detected unless the water contents exceed a certain amount． The amount of
the first－order transition of water varies according to the chemical struc－
ture and／or the higher order structure of each specimen． Before exceeding
this water content’C a broad crystaHizat’奄盾氏@oeak （Peak II） appears at about
230－250 OK． This peak shifts to higher range of temperature with increasing
amounts of adsorbed water． 丁he enthalpy calcu］ated from the area of Peak II
increases with increasing water content until it attains a certain valueg
this water content depends on the number of hydrophilic groups． A new sharp
peak （Peak 1） appears when the amount of water in each specimen exceeds that
needed．@to show a constaBt Peak 工I in a DSC curve． The shape and temperature
of Peak 1 accords well with that for the crystallization of pure water， as
shown in the dotted curves in the figure， although Peak 1 is broadened
一 81 一
sl ightly in the ］ow－temperature side． ln－general， with further increase
of@water the．enthalpy of Pea’k C1@in№窒?≠刀Ces’，．wherbas・一thgt／of Pea’k－II－rerpains
Constant．
工n the case of the crystallization of water adsorbed on cellulose．
specimen， the sum of the weight of water calculated from enthalpies of
Peak 1 and Peak II is less than the total wbight Qf ．added water． The amount
of water corresponding to the difference between the added water and the
amount of water calculated from the DSC must be present somewhere． It rBust
be combined very tightly to cellulose rnolecules to form ’non－freezing
bound waterT i’n contrast to ’freezing bound water’ corresponding to the Peak
II．
Ffigure 5一一21 shows DSC heating and cool ing curves of various amounts of
wat№秩@adsorbed on a viscose rayon． Any kind of first一一〇rder transition of
adsqrbed water is not detected until the water content （moisture regain）
母xceeds l9・6％・ The broad crystalliza bi on peak （Peak I工） apPears at about
230－250 OK in the water content （moisture regain） region from 19．6－23．00／o．
A new sharp crystallization peak （Peak 1） appears at about 255 OK when the
water content （moisture regain） exeeeds 23．Ob／o． The DSC heating curve of water
adsorbed on a specimen also shows a broad peak in． the region of 23．00／， regain
of water，． The overlapping of broad and sharD， peaks is clearly observed if
the moisture regain exceeds 23．0％．
It is appropriate to－consider that there are three kinds of adsorbed
water； fi．e．， nonfreezing bound water， freezing bound－water， and free water，
due to the ．interaction of cellulose molecules and water． Nonfreezing water
having none of the ffirst－order transitfion does not seem to have any kind of
crystallization structure． Freezing bound water （Peak II） and free water
（Peak ’1） having crystallization and melting must have certain kinds of
crystalline structure Which may be the’ same as the structure of natural ice，
regardl’?唐r，of the crystalline morphism． There are nine polymorphfic forms
一 82 一
〇f ice： i．e．， 1， lc， II，．III， IY．， V？ VI， VII， and VIII．50） The structures’
fr・m i・e lV t・ice VIIエ・・e f。、nd。，1y、t ve、ry． ?奄№?@p．essu，e，、。 th。t th，
possible－structures of ice for the freezing bound water in the above DSC’
study can be c・n・idered a・iceエ・1、・II…dlll・Th・maxim・m va1・e・f
melting enthalpy of ice （ice 1） is estimated to be 334J／g and the minimum
value of melting enthalpy of ice （ice III） to be 311J／g from the phase
50 ）・
Table 5－12 shows the amounts’of the freezing bound water， thusdiagram．
calculated， and those of the nonfreezing water， further estimated， for
48）
several cellulosic materials．
The cellulosic materials in Table 5－IG in the previous BET analyses
are not necessarily identical with the materials in Table 5－12， as can be
recognized from some differences in the moisture regain in bulk and in the
degree of crysta11うn『ty． Neverthe］ess， the results in 丁abl e 5－12 for l inen
yarn， cotton yarn and l int， and polynosic， cupra， and viscose rayons may
be appropriate for characterizing the adsorbed waters on the scoured ramie，
scoured cotton， mercerized cotton， and polynosic， cupra， and viscose rayons，
respectively．
Two horizontal l ines， upper dot・一dash l ine and lower broaken l ine， in
Figs． 5－22 through 5－27 correspond to the upper l imits of non’ ?窒??嘯奄獅〟@and
freezing bound waters l isted fin Table 5－12． When comparing these upper
limits of moisture regain for the respective bound waters with the rnoksture
regains at 900／． relative humidity for the calculated BET isotherms with
different numbe“ of multilayers n， the following conclusions may be
deduced：
O The adsorbed waters in the fashion of multilayer or cluster formation
with n as large as up to 6 or 7 correspond to the nonfreezing bound
wa te rs ，一
ii） The adsorbed waters with a few additional numbers of n up to 7 or
一83－
s correspond to the freezing bound． waters， and
禰丁h・…b・df・ee w・t…．・・…ly P・e・e・t i・q・ang・．・f・e1・tive．
humidities hfigher than 90％wlth n 1．argblil than．アor 8． ． ．．
These conclusions seem to be consistent， at least qualitatively， with
those obtained in the fiist section of this chapter for the thermodynamics
of moisture adsorption； i．e．’ C the excess energy TAS being still finite， not
zero， even in a range． of relative humidities as high as around 90g／．， and
the free waters， if any， being sorbed only in a range of relative humidities
higher than 900／o up to saturation． Some discrepancies from the above conclu－
sions may be seen for the cotton specimens， possibly owing to the differences
in the water accesgibil ity between the specimens and the cotton yarn and
cotton l int for the DSC study．
Finall．y， it must be noted that the DSC一 analysis is not isothermal
investigation being responsible to the characterization of adsorbed waters
along with the sorption isotherm curve as a function of relative hurnidity．
Actually， the DSC analysis can only distinguish the free water and the
f’reezing bound water from total waters absorbed and estimate the amount
non
ofAfreezing bound water as a residue from total waters contained without
any experimental evidence． The most firmly adsorbed waters with the largest
excess energy near the dry state can not be detected and be distinguished
from the nonfreezing bound waters． More direct and qualfitative investigations
using some molecular spectroscopies， such as infrared spectroscopy and／or
nuclear magnetic resonsnce spectroscopy， rnust be expected for the charac－
terization of the adsorbed waters． The studies along this l ine is now being
carried out by means of a pulse nuclear magnetic resonance technique．
一 84 一
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一 86 一
T． ljatakeyama， K． Nakamura， and H’． Hatakeyama，’Netsursokutei，．S’．’”””’50 （1980）．
sK堰CNg59M？￥ags，il： Hatakeyama，，and ”’； Hatakeyama， Text．．．Res． 一J．”
K． Nakamura， T． Hatakeyarna， and H． Hatakeyama， Text． Res． J．， 53，
682 （1983）． ， ， 一1玄fl隠e猟1認Wβ，きlllmlllδ諮g灘1峯ヨ2．．．a帽gr騨㌃1． of．賦e「書1・
Table 5－1 Absorption isotherms
Normal Viscose Rayon
at various temperatures for
odried in vacuum at 30 c．
10 Oc 20 Oc 30 Oc 40 Oc 50 Oc
r．h．（o／，） v．p． regain（O／，） r．h．（O／，） v．p． regain（O／，） r．h．（O／，） v．p． regain（O／，） r．h．（O／，） v．p． regain（O／，） r．h．（O／，） v．p． regain（o／，）
4．5
9．0
17．0
27．5
40．0
52．0
61．0
71．0
80．0
91．0
95．5
100
O．414
0．828
1．56
2，52
3．68
4．78
5．61
6．53
7．36
8．38
8．79
9．20
3．23
4．42
6．eo
8．34
10．20
11．94
14．08
16．13
19．53
26．63
33．45
37．93
4．5
10．O
18．5
30．5
41 ．8
52．3
61．5
71 ．2
80．5
90．3
94．8
100
O．788
1．75
3．24
5．34
7．32
9．16
10．78
12．48
14．11
15．82
16．60
17．53
3．21
4．26
5．77
7．87
9．82
11．62
13．54
15，37
18，30
24．57
30．63
37．00
113456789
1．75
3．34
5．88
10．50
13．52
17．18
19．72
22．27
25．61
28．63
2．87
3．97
5．47
7．50
9．30
10，93
12．73
15．00
18．33
23，33
1eo 31 ．82 35，50
5．6
11．0
19．5
32．1
43．3
53．6
60．4
70．4
80．4
9e．3
96 ．1
1 OO
3．09
6．08
10．78
17．75
23．95
29．65
33．41
38，94
44．47
49．95
53．16
55．32
3．33
4．26
5．37
7．85
9．41
10，55
12．42
14．44
17．25
21 ．46
25AO
32．88
6．O
ll．6
20．5
32．5
43．2
52．7
60．1
70．0
80．3
91 ．2
95．6
100
5．55
10．73
18．96
30．06
39．96
48．75
55．59
64．75
74．28
84．36
88．43
92．51
3，14
4．27
5．30
7．47
9．21
10．42
12．12
13．95
16．00
18．99
（29．44）
（28．92）
v．p． vapour pressure in mmHg
Oo
＿ 只只 ＿
vv
丁、bl，5－2． Ab、。，pti。n a，d des・，pti。，1、・th・m・at 30士10C f・・
Normal Viscose Rayon dried in vacuum at 30 OC．
Absorption Desorption
Relativehumidfi ty （％）
Va pour
pressure（mm Hg）
MoisturereG∂．1n ゾ （o／o）
Relativehumidity （o／o）
Vapourpressure（mm Hg）
Moistureregaln （％）
5．5
10．5
18．5
33．0
42．5
54．0
62．0
70．0
80．5
90．O
loe．o
1．75
3．34
5．88
10．50
13．52
17A8
19．73
22．27
25．61
28．64
31．82
2．87
3．97
5．47
7．50
9．30
10．93
12．73
15．00
18．33
23．33
3F．5C
6．O
IO．0
19．5
33．5
43．0
52．5
60．5
70．0
81．0
89．0
］oo．o
1．90
3．18
6．20
10．66
13．68
16．70
19．25
22．27
25．77
28．32
31 ．82
3．63
4．85
6．68
8．80
10．89
12．50
14．40
16．13
，19．74
25．18
35 ．．50，
一一 69 一
Table 5一一3． Absorption isotherms at 30 ± 1 OC ’for Normal Viscose
Rayon．dri’ed in vacuum at variously elevated ternperatures．
Relativehumidity （o／．’）
Vapourpressure（mm Hg）
Moisture regain （o／，）
o c60 90 Oc 12b Oc
6．0
10．0
19．5
33．5
43．0
52．5
60．5
70．0
81 ．0
89．0
100．O
1．90
3．18
0r．2e
10．66
13．68
16．70
19．25
22．27
25．77
28．32
31．82
3．00
3．92
5．41
7．l1
9．12
H．15
12．70
15．22
18．85
25．63
4］ ． 2． 0
2．41
3．55
5．13
7．16
9．70
10．77
12．40
14．79
17．69
Z5．C4
38．38
2．28
3．34
4．81
6．82
9．06
10．96
12．54
14．41
17．30
Z3，46
35．Cv ro
一90一
Table 5－4． Desorption isotherms at 30 t 1 OC for Norma－1 Viscose
Rayon soaked ln hot water at different temperatures．
Relativehumidity （．／S）
Vapourpressure（mm Hg）
図Oisturerega in 〈 o／， ）．
60 Oc 90 Oc
lOO
94．0
79．4
69．0
58．7
51．4
41．8
30．8
18．6
10e3
5．0
31．82
29．91
25．26
21．95
18．68
16．35
13．30
9．80
5．91
3．27
1．59
34 ．1 9
29．02
19．67．
17．07
14．83
13．14
11．42
9．33
7．13
5．47
4．15
35．92
30．06
20．10
17．19
14．94
］3．28
11．36
9．31
7．19
5．47
4．20
Table 5－5． Absorption
at 30 Oc．
Isotherms at 30 ：’ 1 UC for Natual Cellulose ．Fibers dried in Vacuurn
r．h．
Scoured
ロregaln
ramle
十r．h．
・十regaln
Scoured Cotton
r．h． regain
Mercerized
r．h．
cotton I
のregaln
Merceri’zed cotton II
r．h． regain
5．7
10．7
19．2
30．6
42．3
51．7
59．2
67．9
78．8
90．3
94．8
100
1．67
2．28
2．92
3．77
4．79
5．40
6．40
7．34
8．67
11．94
14．76
20．13
14．3
26．7
37．4
49．0
66．7
2．30
3．60
4．00
5．50
7．80
6．2
11．0
19．5
31 ．2
42．3
51 ，6
59．0
68．3
79．2
90．0
94．8
100
1．66
2．37
2．84
3．72
4．71
5．54
6．33
7．09
8．77
12．18
14．25
18．63
6．O
H．0
192
30．5
42．3
51．2
59．2
68．1
79．2
90．0
94．7
100
2．48
3．19
4．10
5．53
6．70
7．86
9．12
10．66
12．89
17．60
21 ．91
31．08
5．5
11．Q
19．8
31 ．6
42．3
51 ．7
59．0
67．8
79．0
90．1
94．8
100
2．61
3．48
4．43
5．85
7．27
8．69
9．83
11．67
14」5
19：一70
23．06
30．70
12巳
十
Measured by sorption balance method in vacuumat 30．o ± o．1 Oc．
Table’5－6．’Absorption isotherms at 30 ± 1 OC for Normal， High－tenacity，
．9．n．（．．P．9．IY．PPS’ic’ Raygns） all dried in vacuum ap’．30 Oc．
Cuprammoniu，
N o rmal vi sc g． se ra y On
r・hr ．．．．，regai．n・
High－tenac’ity rqyon
・r・hr．，，．．． ，regqin
Cup 窒≠高高盾獅奄浮香@r’a＞ton
rrhr ／． regain
Polynosic raYon
r．h． rega in
5．5
10．5
18．．5
33．0
42．5
’54．0
62．0
70．0
80．5
90．0
100，0
2．87
3．94．
5．88
7．50
9r30
10．93
12．73・
1s．eo
18，33
23．33
35．50
7628788151．80
ロ ロ
ロ コ の サ サ
1．1345567990．．
1
3．57
’4．74
6．22
7．93
io．08
11．75
13．46
’15．22
18．82
24．56
31．22
42．07
6．1
10．8
19．4
30．6
42．5
51 ．5
59．2
68．1
79．2
90．3
94．8
100．Q
2．7ti
3．88
5．17
7」2
8．72・
10．09．
11．54
13．48
16．28
22．21
’28．03
40．37
5．0
10．3
18L6
30．8
41 ．8
51 ．4
58．7
69．0
’79．4
91 ．2
95．6
100．O
2196
41．11．
5153
7113
8．・i．73
1．
E二・5．
11i．42’
13．21
16．07
21 ，1 g
26 ・1 64
37rO5
O℃
監 「
Table b一一／． Absorption isotherms at 30 ： 1 ’U
Fibers dri．ed in vacuum at 30 Oc．
for Cellilose Derivative
r．h．
Di一一a¢etate Rayon
十
regain’ ’ r．h． ．十regaln r．h．
Tri－acetate Rayon 十regain ． r．h．
，十regaln
Na 一一CMC
r．h． regain
6．2
11．0
19．5
31．2
44．5
51．5
59．0
67．6
79．0
90．1
94．7
100
O・． 587
0．702
1 ．4 35
2．59
3．62
4．91
5．61
7．04
8．59
10．95
12．15
13189
7．28
13．83
25．96
34L70
40．28
o．se
1．IQ
2．20
2．70
3．80
6．2
10．8
19．4
30．6．
42．3
51 ．2
58．5
67．9
79．0
89．6
94．8
100
O．127
0．465
1．02．
1．80
2．54
3．30
3．99
4．86
6．01
7．72
8．49
9．50
7．76
14．80
27．18
32．5i
42．46
O．30
0．50
1．30
1，70
2．30
6．1
11．O
ls．g
31 ．2
42．1
51 ．0
5818
6g．2
79．0
89、ブ
94．7
100
4二1．P、
5 ．’ 40’
ブ，45．
・”
X ，99
11・．剤
肺．
17・Q
．己20・1～：
．25 ．． 9．
44．． 9，
59．91
．90．9i．
＋ Measured by sorption．’ b≠撃≠獅モ?@method in vacuum at 36．o ± o．1 Oc．
一
））
ば鉱
Table 5－8 ． Absorption lsotherms at 30．0 ± O．1
Films dried in Vacuum at 30 OC，
o C for Cellulose Acetate
EEt－JJIiM一一5El．700 ac5111yl－i－ation
r．h．（O／，） regain （％）
5 5 ． 0 O／， a c e tyl a t i on
r．h．（O／，） regain （‘／，）
61．6 O／， acetylation
r．h．（O／，） regain （o／，）
7．52
13．59
21 ．84
23．54
33．24
42．71
50．刀
53．14
55．08
63．33
78．13
1．60
2．80
3．40
4．00
5．20
6．40
8，20
8．50
9．20
11．0
16．2
6．55
15．29
23．54
25．48
35．91
46．10
54．60
59．93
69．40
88，08
O．50
1．40
1．70
2．00
2．90
4JO
5．00
5．60
7．30
11．8
8．49
15．04
19．17
25．72
31 ．79
42．71
53．38
66．49
74．49
O．50
0．70
1．00
1．60
2．20
2，70
3．6e
’5 ．90
6，40
＋ Measured by sorption balance method in Vacuum at 30．0 t O．1 Oc．
－り恥－
一一 95 一
Table．5－9． Values of v m
’isotherins of
and C ’ ?盾秩@absorption
Normal Viscose Rayon
and・’desorption
oat 30 c i一
v m
c
absorption
desorption
O．0582
0．0665
14．1
16．7
Table 5一一10． Effects of drying and water－soaking temperatures upon
the values of vm and C for absorption and desorption
isotherms of Nornal Viscose Rayon at 30 OC．
absorption
Drying
（oc）
te叩．vm
c
60
90
120
O．0559
0．0577
0．0574
14．8
10．6
9．1．4
desorption
Water－soaking temp．
（oc）v m
c
0（）
広∪OJ
O．0708
0．0703
21．4
22．5
in Terms o’f BET Parameters．
Specification v m
c nmax
十X x
Moisture regains at 900／， r．h． Moisture tegain
n＝1 n ＞n＞1 maxn
at 650／， r．h．
＞ n in bulk max
Scoured ramie
Scoured cotton
Mercerized cotton I
Mercerized cotton II
Normal viscose rayon
Cuprdmmonium rayon
Polynosic rayon
High－tenacity rayon
Di一一acetate rayon
Triacetate rayon
Na 一Carboxy methylatedrayon （18．3 wt．O／， c．tn．）
Acetate film（44．7 wt．O／， ace．）
Acetate film（55．0 wt．O／， ace．）
Acetate fi］m（61．6 wt．O／． ace）
7440●
0
3 30・
0
9820・
0
QO4
891914579］0
］ 1 1 1 1 1 1
1 1
2 7
4 戊
∪
にU つ乙
879
1
戸0 4） 4
55 （e／，）
50
39
37
34
37
40
27
16
19
18
2．8 （”／，）
2．7
3．9
4．2
5．4
5．2
5．2
5．9
2．2
1．7
7．2
3．9
2．2
1．8
6．5 （O／，）
6．3
9．1
9．8
12．8
12．6
12．1
13．7
6．7
4．2
17．1
10．0
7．1
4．1
2・6 （O／e）
3．2
4．6
5．7
5．1
4．1
3．3
5．0
2．0
1．8
20．7
7．5
2．9
4．0
’6・9 （O／e）
’6．8
i，o．b
lo．7
13．3
12．7
i2・ e14．6
6．5
，4T5
18T8
11．5
fi・5・
15．2
⑩①
響
＋ Maximutn number of layers beyond whic6 the calculated moisture absorption exceeds
the experimenal one at intermediate range of relative hurnidity．
Table 5－12． Characterization of Adsorbed Water by Differential Scanning
十 Calorimetry for Cellulosic Materials at Room’ Temperature
SpecimenDegree of crysta－11inity， X ×
（％）
，2fE6C62i， ge，ZaJe，．
（鬼）
Non－freezing
（％）
Moisture regains Freezing
（o／o）
Total bound
（完）
water
Linen yarn
Cotton yarn
Cotton l int
Wood cellulose
Jute
Kapok
Polynosic rayon
Cupra rayon
Viscise rayon．
1 1 1 1 1 1
IO．5
14．0
17．8
18．6
18，4
14．9
19．8
18．0
］9．6
O．8
2．0－2．T
2．1 一2 ．2
3．8一一4．1 ・
5．5－5．9
7．9－8．5
1 ．4－1 ．5
3．7－4．0
3．2－3．4
ll．3
16．0－16．1
19．9－20．0
22 ．4 ：’Q2 ．7
23．9－24．3．
22 ．8－2 3i ．4
21 ．1 一21 ．2
21．7－22．0
22．8－23．0
1
〈o
刈量
十
K． Nakamura，
Differential
T． Hatakeyania and H． Hatakeyama， Studies on Bound V“ater ofScanning Calorimetry， Text． Res． J，， 51， 607－613 （1981）．
Cellulose by
一98－
Captions for Fi．g－y．r－e－s一 一一． 一
Hg，5－i．T・1・i・加・e ab…pti・・．i・・th・“・6．・t．vari・・s t・mp・．・a七・．・e．・一一f・卜．．．．・・一．．．・．・／．
soda－boiled cotton by UrqUhart and Williams．
Fig． 5－2． Moisture absorption isotherms at various temperatures for
normal viscose rayon．
Fig． 5－3． Moisture absorptiOn isothbrms at various pemperatures for
normal viscose rayon plotted against partial vapoure pressure，
Bot relative humidity．
Fig・5－4・P1・ts。f diff・・e醐・1 heat・f・・ist・・e…pti・・QL・g・i・st
relative humidity for three kinds of cel lulose fibers at 30 OC．
Sol id curve of QL is the results by Rees and Guthrie for 14
kfinds o’f cellulosic fiber and sol id cvrve ．of AG is calculated
from Eq．（6）．
門9．5－5．円・ts・f excess e・ergy（T△S）・・d・hange i・d・t・・py（△S）agarn・t
relative humidity at 30 OC． Sol id curve is the result，s by Rees
and Guthrie for 14 kinds of cellulosic fibere
Fig． 5－6． Absorption and desorption hysteresis at 30 OC for normal viscose
rayon．
Fig． 5－7． Absorption isotherms at 30 OC for normal viscose rayon dried
in vacuum at different temperatures from 30 to 120 OC．
Fig． 5－8’． Desorption isotherms at 30 OC for normal viscose rayon soaked
fin water bath at dfifferent temperatures from 30 to 90 OC．
Fig． 5－9． Absorption isotherms at 30 OC for four kinds of natural cellulose
fiber．
Fig． 5－10． Absorption isotherms at 30 OC for four kinds of regenerated
cellulose fiber．
Fig． s－H． Absorption isotherms 6t 30 Oc for three kinds pf chemical’ly
modified cellulosic fiber i’n comparison with that of normal
vlscose rayon．
い
21一
5
●
31一
5
041
一5
●9●
－F
●9p
l
F
99。
－F
0
51一
5■
9．－
F
061
■5
●9．
－F
●
71一
5●
9。－
F
Fig． 5－18．
Fig． 5－19．
Fig． 5－20．
Fig． 5－21．
一99－
Absorption－isotherms－at． 30 QC for three ．kinds，一・of．cel－lulose ／gcetate一一
｛ll錦：謙ご：1二1．．£．弓cetyla 二齢∫qO脚sO唾lth．
Linear plots of h／｛v（1 一 h）｝ against relative humidity h to’
．：？ぎ：rマ：二2h：：2sB：7 ：：：二：↑ 5：ξ』乙τea： y：；1：：r3：b：2：ption 莞nd dgso「T．
compari’ 唐潤f氏f@ok ’abgor’垂狽奄盾氏@is6therm obserVed’i6“ n6r’mai viscose raYon
at 30 0C with those calculated from BE丁mult『layer adsorption
th…y・keepi・g BE丁・…tant・vm and C・t O・0582・・d 14・1・re・pec－
tively， but varying the number of multilayers from unity to infinite円・t・〈21icui・t・d・・i・t・i一・・eg・i・・with・・1・n’d・ml。…1
against vm for various cellulosic fibers at 30 OC and 900／， rela－
tive humidity．
Plots of degree of noncrystaH inity against vm for three groups
of ceHulosic fi．bers， acetate fibers， natufal cellulose ffibers，
and regenerated cellulose fibers including Na一一cmc fiber．
Plots of calculated moisture regain with n ＝ 1 （Langmu．fir’s
monolayer adsorption） agafinst vm normalized by degree of non－
crystallinity for varfious cellulosic fibers at 30 OC and 900／，
relative humidity．
Plotsi of C against number of hydroxyl groups per cellobiose unit
for various ceHulosic fibers at 30 OC．
Plots of ’ヒhe value of C agains’し normalized v by degree of non－ m
crystallinity for various cellulosic fibers at 30 OC．
Schematic diagram indicating the DSC curves during cool ihg and
heating cycles of moisture sorbed textiles by Nakamura， Hatake一一
yama and Hatakeyama．
Dsc curybs during cool ing and heating cycles of a normal viscose
rayon sorbing different amounts of’ water．by N． H． and H．
Fig． 5－22．
Fig． 5・一23．
Fig． 5－24．
Fig． 5－25・
Fig． 5－26．
Fig． 5一一27．
一 IOO 一
Comparison of the calulated moi’sture adsorption isotherms varying
t脚ber．・f・醐・y・r・・f…c・・h・d一 而6・一at・3・．ρC．．・ith．．・pP・r…
1’ 奄高奄狽刀@of nonfreez．ing’（broken l in’e） and frde2ing・，（da’sh－dot l ine）
bound water contents determined by DSC analysis by N． H． N． for a
linen fiber．
．Compqrison of the cgJgglateq ．moisture’ ad．s， orpt’ion． isot．herrps一 vg／r． ying． ’，，，
the number of multilayers n for scoured cott6n at 30 Oc with’ upper
limits of nonfreezing （broken l ine） and freezing （dash－dot l ine）
bound water contents determined by DSC analysis by N． H． H． for
cotton l int and cotton yarn．
Comparison of the calculated moisture adsorption isotherms varying
the number of multilayers n for mercerized cotton II at 30 OC with
upper l imits of nonfreezfing （brqken l ine） and．freezing （dash一一dot
li・e）．b・岬・・t・・cg・t・・t・d・t・・mうned by DSC・・aly・i・by N・H・H・
for cotton l int and cotton yarn．
Comparison of ehe calculated moisture adsorption is’ 盾狽??窒香Cs varying
the number of multfilayers n for polynosic rayon at ’30 OC wfith
upper．limits of nonfreezing （broken l ine） and freezing （dash－dot ］ine）
bound water contents determined by DSC analysis by N． H． H． for
polynosic rayon．
Comparison of the calculated mofisture gdsorption isotherms varying
the number ’ 盾?@mul tilayers n for cuprammonium rayon at 30 OC with
upper l imits of nonfreezifig （broken l ine） and freezing （dash－dot
line） bound water contents determined by DSC analysis by N． H． H．
for cuprammonium rayon．
Comparison of the calculated moisture adsorption isotherms varying
the number of multilayers n for normal viscose rayon at 30 OC with
upper l imits of nonfreezing （broken l ine） and freezing （dash－dot
line） bound water contents determined by DSC analysis by N． H． H．
for normal viscose rayon．
Sodab－boiled cotton
02だΦり
しΦα
51
10 5
⊆而0Φ」Φ」ヨいるΣ
o
COO5
COO4
COO1
COO5
COO
COO3CO
02 C
20 40 60’ 80Relative humidity
o 20 40 60 80 ・ 100Partial pressure mm Hg
’
HO一t
Fig． 5一一1．
一 102 一
O守
Ooっ
（δ
ON
⊆昭0Φ臨Φ」コρりり甲OΣ
O門
o
o
e
ム
口
嘱
IO Oc．
20 Oc．
30 Oc．
40 Oc．
50 Oc．
O／●
t
●△
口
／
口
／
／国
／06ロ翼
@
Normal viscose rayon
o 10 2030 40 50 60Relative humidity （％）
Fig． 5－2．
70 80 90 1OO
（訳）ε9實窪3。。ちΣ
○ぐ
Oの
ON
O門
。
吟
。
」Qーー～
口
IO
一 103 一一
ノ
a／”
口
／．
。／
口
．．6／’
O ： IO Oc．
e ： 20 Oc．
A ： 30 OC．
ロ ：400C．
醒 ：500C．
Normal vfiscose rayon
一●
20 30 40 50 Pa，rtial pressure
Rg． 5－3．
60
（mm Hg）
70 80 90 100
一 104 一
OOの
O鵠
OON
」¢9邸三で㌣コσ㌣門甲。」⑰＼罵O
O學
OO門
∩（O〈）
で⊆邸
」α
Oの
o
o o
O ： Soda－boiled cotton by Urquhart et al．
： High－tenacity rayon by Jeffries
A ： Viscose rayon by this work
Al l at 30 Oc．
X〈A ．
o Q岬製些 e
A
o
AG calculated frorn Eq．（6）
A
AOA zP
ooo 10 20 30 40 50 60
Rel a ti ve humi di ty 〈 o／．）
70 80
Fig． 5－4．
90 100
OOeq
O頃［
OOP
鼻ω9而3でヨσ二仏。」⑰＼［8“
（のぐじ合乙⊆Φ・。の8×国 O
の
o
e
o
e
“rs
o
e
o lo
e
○△
20
105 一
A
○●△
o e
o
： Soda－boiled cotton by Urquhart et al．
： 卜iigh 一一 tenacity rayon by Jeffries
： Viscose rayon by this work
All at 30 Oc．
by Rees and Guthrie
o
Ao
A
．
oAA ，g・ g．
30 40 50 ・ 60Rel a t i v e h u mi d i ty （ O／， ）
Fig． 5－5．
70 80 90
ゆ．
n
u⊃
DO
ぐ．
n
yo＼鼻。＼［邸Q
。っ．O
♂〈
詮。ち⊆］
N．O
ド．
n
olOO
一 106 一
O寸
Ooっ
8（訳
jεg隻Φ≒冨至
OF
o
Jt＞LgmpLmy．！EsgEe－rwg！Lormalvlscosera at 30 Oc．
Desorption
e
ノニ．
e
o
Absorption
y9：／一
o 10 20 30 40 50 60 Rel a ti ve hu mi di ty （ o／，）
70 80 90 100
Hg． 5－6．
1 n7一 上uノ 一
OON
OOF
○ゆ
O。り
ON
A一駅v⊆昭02Φ」「P9りFOΣ
○［
O．ゆ
O．。っ
O．N
O．．［
ゆ．O
。っ
DO
O ： 30 Oc．
e ： 60 Oc．
口90 Oc．
膿：1200C．
．／暫／
でP㌔へ
”］’@kabsO
KO“〉 ／一
3b’ OC
．TY ／ロ
ンe．
盈／一
120’Oc
2t1gun｛xLyLsggEe一！2gMgn－o ．rmalvlscoserao
o 10 20 30 40 50 60 70 80 90 100
R el a t i v e h u mi d i ty （ o／． ）
Fig． 5一一7．
一 108 一
O寸
Oρっ
8
（隷
jε9隻
9
Φ」コρしり甲OΣ
o
06口
30 Oc．
60 Oc．
90 Oc．
口
。
ノ2i’
奄奄撃撃戟Glll：iiaili’1；ll；iil；：ll．gi
ノ＼3。・。
：：，i．，，，2“！；JJ’；／／g
一Ntg！gusgEg：gMgn．1
o IO 20 30 40 50 60Relative humidity （％）
Fig． 5一一8．
ア0 80 90 100
一 109 一
O寸
O的
（訳
j ⊆学灯a①」 ①」＝ρの炉OΣ
ON
OF
o
O薩ロム▲
O ・
Scoured ramie
Scoured ramie by S．B． method
Scoured cotton
Mercerized cotton I
Mercerized cotton II
at 3e Oc．
／
〆ダ
e
／
駐
o 10 20 30 40 50 60 Relative humidit．v （O／，）
Fig． 5－9．
70 80 90 1OO
一1ユ0一
O寸
弊一着
O。っ
ON
（訳
jε8①鼻
9
Φ」⊃ρの甲OΣ
f
r
O畠 ●●
●畳
○礁△耀
Normal viscose rayon
High－tenacity rayon
Cuprammonium rayon
Polynosic rayon
／‘Eytzi’v
at 30 Oc．
、一
／ 7
／亭
ノ
o
g
！
多ク
多タ多as．
o lo 2030 40 50 60Relative hurnidity （O／．）
Fig． 5－10．
70 80 90 100
一 lil 一
OO「
一EB 一
…一一一一 Z一一一一
CXI’
ロ富O②△▲
．．一一｝．ノ
じ へ
ド… 「．一」．
…ドーpしーレー」レ」i
。ピ
c
D…、6密
…「
?c
p（ｫ〔 …
㎝ …．．
⊆ド
∑b
．。．N ♀「」
Φ§・・奎 三
｝ 一
．O
盗…｝
・一
グ
●●
●O
●，
●●
■O
Na一一carboxy methyl cellulose
Viscose rayon
Di－acetate rayon．．
Di－acetate rayon by S．B． mathod
Tri一一acetate rayon
Tri－acetate rayon by S．B． method
．一．一．．`
一一……@e ／一一一
一…一一@一一一一／一 O 一一
IJ£1’IJII／iJJI
at 30 Oc．
一 一／…1
ノ
・ノノ’．
σ ゴ． ．．
’e；」）一6
1！1／rAl ．一／“
A
．○／一
（Y一一一
“ ム／ム．．’D”’狽煤^li ．r・1－1．11
1司0
『O
A
10 20’ 30 40 50 60’Rel a ti ve hu rni di ty （ o／， ）
””” eig：” 5－ll ．
’．
V0 80 90 100
一 112 一一
O寸
Ooっ
（訳）
．ON
⊆門9Φ」
O
Φ』⊃ρの甲OΣ
OF
o
00△▲
at 30 Oc．
： Normal viscose rayon by W．B． method
： Cellu］ose acetate （44．70／． ace．）
： Cbllulose acetate （55．Oo／，i ace．）
： Cellulose acetate （61．60／， ace．）
e
／／
7
A／
△／ムA
A
e IO 20 30 40 50 60Relat fi ve humi di ty （ o／， ）
Fig． 5－12．
70 80 90 100
一 113 一
のN
ON
聖
［（
圏
［）
r］＼£
O門
頃
o
Normal viscose rayon
at 30 Oc．
O ： absorption
e ： desorption
○●
o●
o
o 10 2030 40 50 60Relative humidity （o／，〉 70 80
Hg． 5－13．
90 ］oo
鴇
ON
ゆ門
O門（
訳） ⊆甲邸mω鼻 ωL「5……憎OΣ
ゆ
oo
一 ！14 一
n ＝ co
Normal viscose raYon
at 30 OC （absorption）
－～！－一
や●●
O・
Experimental
Calculated with
v ＝ O．0582 m
c ＝ 14．1
Xi・
ri・
（Langmuir’s mono一一1ayer adso rpt 1’ @On）
n ＝
n ＝
n＝5
n＝3
n＝1
IO 20 30 40 50 60 70 80 90 100
（⊆
Bコ巳。の昭お診［諄ガ」E＝〈 二 く
×ゆE
二
5三訳εε92望3・，甲。Σ
。○
u
箪
寸［
N【
Oρ
oo
ゆ
噂
N
O
一115
Cellulosic Fibers and Films
a n d 9 0 0／， r el a t i v e h u m i d i ty％at 30
2．5 acetate
acetate3響
◎○
@ ト ゆ 頃 ぐ 。り N ド
（⊆。；αきので応お詮丁○⊆。E。，一」炉．建。⊆ヨ）7⊆5三訳ε⊆［呂2豊β碧。Σ
O 876543210
210X m
V
5－1 5．Fig．
一 116 一
Cellulosic Fibers
at 30 Oc
●●
●
●
〆／ぱ ゴ
ofQ7
ざ ．Nb Qe ／o
絶○爵
ぼっ嵐kノ
〆○
OOF Oα OoD
O卜 Oり
O頃
O守〔Ooっ ON O【
（×－【）．駅⊆三＃壱、ρ塾・と。ε。8δΦ。
O8765
、凪
卜
4
鳳 F
2
v 2mx IO
310
一 117 一
Or
a
◎っ ト ⑩ の
（⊆
Bおαき・。幕乙詮7。⊆oE・・一諺＝葛⊆ヨ）F⊆
二ρ吟≧試 ⊆甲 ⊆ド娼⑪Φ」 ΦLJρしり府OΣ
ぐ
の
ov
r
o
At 30OC， 90銘 rのh．
Di－acet．
Na－CMC
H．丁． rayoncup． rayon’@．×
e
po］ynosic RVis． rayon 一一pt一 e
Merc． cotton IIx e
Merc． cotton 1一
Sco． ramie
Sco． cotton
e ／rayon e
×丁ri－acet． rayon
×
o 1 2 3 4［・m／（1－X，）コ・］・2
5 6 7 8 9 10
Fig． 5－17．
一 118 一一
ON
At 30 Oc
ot一 Polynosic
O／隠Σ：：誰繍
§蒙il籔劉
I
II
rayon
1
uっ
O門
の
O㌣OΦ＝ド邸〉
Na－CMC raygn× o Q
’“ Vis． rayon
O．‘一一一Cupra． rayon
／
o
8
oo 1 2 3 4 5 6
Number of hydroxyl groups per cellobiose unit
Fig． 5・一18．
119
ON
津
O門
O甲OΦ⊃［価〉
の
。
e
e ee o
o
e ： Natural cellulose fibers
O ： Regenerated cellulose
fibers
膣：Acetate rayons
A ： Na－carboxy metylated
rayon
at 30 Oc
oo
A
臨
薩
o
1 2 3 4［ v．／（i 一一 x， ）］ × io2
5 6 7 8 9 IO
Fig． 5－19．
一一 120 ・一
；
一
P且」「ρ「「「竿卜
「p盈
，ノ
．這
：」‘争「5－i碗3亀「脚璽■7｝「雪宵盛「7回
一
一
Peak II
／l
i’
l
〔絆
1
「一一 一一一一．’
！
t ノ’： 」一
一～～喉
一蓋一
Peak 1
一誓ξ
髪看～匹疑皇と
｝
’
｛
ζ し ； ｛ レ 1 …
… ； ｝
二 望 … …
i
C。。1漁 i §
＜←一一一一一一t－i ‘ …
1
3三乙50℃⊆］
i）pt
’whewm 一
「 一
@ @ @一
@ 一
一
聖鵬ーーー「＝」トー「邑 吐唱▽じ，垂，」
一
二「！き年」」藍屋‘
蚕塁1
・
1 ．一一
；li
u L－pt一．一．一一．一．一一
ロー． ﾏeatlng
1
、「「一 ノノ ヒ
，！」～
一 「 ーー ‘ 一
，．／ノ “
ノノロ
・、，一亨ノゾー
．＼＼
＼＼＼製
h）
」3‘｝【～「｝F「；t」ε「8．－r「「」…
190 2］O 230 250 270 290
Tennerc一，tum， e， （OK），
Fiq． 5一一20．
9甲∈」Φ二ρOで⊆田
｝甲
幽…一騨一一♂
一山耐一「ー
ー旨．もド
廼鱒」考配
滞 岡
～｛一
～馴脚轟誌 曜
暇
・璽1…ーー曹
仰
騨繍 ～一項
一 ～
．．ード母P
．－』：ノ
、
．「｝
、
㌦
FI－－－：雪r』i－「』」r－11．－」』．－111」「－－．：11唱1』．：一「－＼〔b－－．－
＼
＼
：．－．ri＼
H＼
k
・．：a一．
e P
陶
…．（、
〔7μ晶
h恩」
塵． ．
畷
｝炉脚，
』屑幽姻
ρ
1kaeP
一胸
…』
－一、
cooling
’‘EEEi’一“一nv一’“v一一’L一’一一一r一一一・
ノ、一一”・ 一；”Li・pm－L一
X．．．一一一一a
弓lll：：就∴
コ ヨ
圏 ド ： ｝ ． ！ β2夙］．
I F I ・ 1 ロ
㍉ l lI I
I ：
［ 1 』 2 1 ■ 1・
： r ：コ ト
一｝ ト
ヒ旧辞・』i．…
1 ． ｛ ． ・ 1 1 ． 1 ．
1 ト
・ 旧し1一一． 1 ［ ll lI Ir ：一 ∴■
峠 『… s 叩一剛’ u二一‘
一a」，．¥一“A－F一一
i
i層 i
叫｝’
｝…，P
【一←
…”一一
」
早
瓦
i ’
÷｝『 外_1・
了
、
一－誌
．一
｝
「 ． ’レ
r』｝ ・ ．
H20 P（％）ll ロ
1 ．1： 1 、 ：32．1 ： i
23．O
19．6 ｛ ［ ．『h li．－』
」一一一一；＿1＿晶＿＿1＿＿＿一．
…
L
1，〉
’liN
・Li，
il－li
ーヨノ
〆／一 一”｝
／
｝
；・．
D ド
：i： EI 1
． 2 1
@ ；
l i戟@lE
1 1 ． … …
EF沼Il I一 1
v2 「．
0 1@…
黶@1． 一
semper塩tu｝（e，
旨 …
奄Q50
@ 1
1 … ．
iOK）
i211・1L 一 」 ， 「
li．27・1 1冝
@ i
「奄Q80 1
マ
Hq． 5一一21．
」三
朝｝榊
鯉「－一r
｝
1
爲H1
ON
頃｝
OF
（駅）輯島露田3。。刺。渇
4
．0
一 122 一
n ＝ co
Scoured
g，Lg919一くgPsgllx！．！gnit30C（absot）
ramle
o
一〇一一一，O
●●
’Experimental
Calculated with
v．“ ＝ O．0290 m
C ＝ 17．8 ’
＝＝＝＝ ＝ ＝
（Langmuir．‘s mono一一layer a．dso，rption）
10 20 30 40． 50 60 70Rglative humidity （％） 80 90Fig． 5－22．
100
一 123 ． t
”P F・og
ON
のr
OF
（駅）ε㊦bD露．鶏3。，哨。Σ
n’
Scoured cotton
g一1tE－39一一9！Lg－gUEg2zR！pt）一30c（b t）
．
一〇一1
：
’Experi・menta1’．
Calculated wit．h
v ＝ O．0290 m
・C ＝ 17．9
（cotton l int）
一・
（cotton yarn）’
8．765
＝＝・＝篇
n．nn．nn＝3
n
（LangTTiu．ir’s mono－1ayer adsorp．tion）
＝1
10
10 20 30 40 50 60 Relative humidity （％）
70 ． 80
Fig． 5r一’23．
90 i’oo
一 124 ．．
n ＝ ・co
ON
ご〕．．．
．O
（N）d完bD鎖①旨三。。嘱。Σ
頃
Mercerized cotton’II
gt！nt｛｝g2！2－g－g！？sgtp！1－g！［L）Lt30C（absort）
1
’一〇r’ ：・
一一一一一 ：
Exp6廟年ntal
Calculated with
vm ＝． o．044．6
C ＝ 18．9
（cotton lint） n＝8
n＝7
（cptton yarn）
一 一 一
n＝6
n＝5
n＝3
n＝1
（Langm頃r’s m・n・一］ay6・ads・rpti・n）
o 10 2030 40 50 60 Re1．at二ive humidity（％）
70’ 80 Fig． 5‘24．
90 100
一 125 一一
n ’＝ oo
ON
頃｝
9
（展）ξ島①冨田ε紹。Σ
LA’
Polynosic．rayon
twttQOC（absortion）
一r〈〉一．： Experimenta’1
繭 一
n＝8
：
n＝7
Calculated with
v．． ＝ O．0547 m
C ＝ 19．5
n ＝6
n ＝5
n＝3
（Langrnuir’s mono－1ayer adsorption）
n＝1
o 10 20 3040 50 60 70 Relative humidity （7．） 80 90
Fig． 5一一25．
100
一 126 一
n ＝ oo
ON
（駅）輯㊦bo田鶏β鞍。
頃F
○ド
頃
Cuprammonium・rayon ／n＝8
oat 30 c 〈．．ab．s o．rpti on ）
一〇一一 の．
●，
EXperimental
Calculated with
v ＝ O瞬0559
m
C ＝ 13．4
”
n＝7
n ＝6
一 一 pt 一 一 i 一
n＝5
n＝3
’（Langmuir’s mon6－layer adsOrption）
n＝1
十
o 10 20 30 40 50 ・ 60 70 Relative hurnidity （％） 80 90
Fig． 5－26．
100
一一@127 ．t
n ＝ oo
（N）輯邸bo讐雪β紹。
ON
鴇
OU
4
N．pr－m．a．．」 ．viscose rayon
aLS｝L3Q一 OC （absorption）
・一一b＞一一
，●
●O
Experimental
Calculated with
v．． ＝ O．0582 m
C ＝ 14．1
t
n＝7
1
n＝6
n＝5
n＝3
q
（Langmuir’s mono－layer adsorpti．op）
n＝1
o 10 20 3040 50 60 70 Rela亡ive humidity （％） 80 90
Fig． 5－27．
100
一 128 一
gth！gg！g12－S一，riggnglLya p t e r 6． Conclusion
Twelye kinds of test specimen i’ncluding natura．1 ，’ regenerated， an．d 一 …
chemicaHy modified cellulosic’ fibe’rs， were prepared for measuring the
moisture absorption and desorption isoth．erms at various temperature from
］O to 50 OC． Two kinds of natural fibers l ramie and cotton， were scoured
r・a・athe・而1d c・nditi・n with 2％aque・us s・］uti・n・f NaOH at 1100C f・r
one hour to remain their crystal structure unchanged in the cellulose 1．
The scoured cotton was further furnished to prepare two kinds of mercerized
cotton by soaking in 18 and 350／， aqueous solutions of NaOH， respectively，
at a room temperature of around 20 OC for about one day to produce alkali
ceUuloses， the so一一called Na－Cell－1 and Na－Cell一一II， leaching in running
water for several days to remove the alkali and to reduce the alkali cellu－
lose to cellulose hydrates， and drying in air and ultimately in P20s to
obtain the specimens having crystal structure of the cellulose II． The
change in the crystal structure during the mercerization process has been
coRfirmed by ，means of X－ray di．ffractfion．
Four kinds of regenerated cellulose fiber were furnished from fac－
tories； a normal viscose rayon， a high－tenacity viscose rayon， a polynosic
rayon， and a cuprammonium rayon． Fourthermo－rp．．， four kinds of cellulose
derivatives are added； i．e．， two kinds of acetate rayon differing in the
degree of acetylationl，’a di－acetate rayon and a tri－acetate rayon having
55．2 and 61．6 wt．O／， acetylations， respectively， both with respect to a
glucose unit， a sodium－carboxymethyl cellulose fabricated in a forrn of
nonwoven fabric with 18．3 wt．％ Na一．’carboxyrnethylation also with respect to
a glucose unfit， and a noncrystalline cellulose， not in a form of fiber
but of powder， being obtained from powdered and fully dried tri“一acetate
by saponiffication in 10／， sodium・一ethylate solution in anhydrous ethanol for
one day at room temperature．
L129一 ’
All of these fibrous specimens， with exception of the Na－cmc fabric，
were p・・ifi・d by・S・xhl・t・xt・・t・・u・ゆ而・加r・．．・f benze・e．and・th・「i・1
with a vol’ume ratio of 2 to 1 for the cellulose fibers and ethyl ether for
the acetate fibers， respectively， in order to remove oil or fatty materials
used in spinning and／or finishing processes， if any． The degree of crysta一
］linity of these specimens were estirnated by means of X－ray diffractien
as well as from’ 狽??@measurement of the bulk density of the specimens at
30．0 OC．’@Two types of apparatus， both basing on gravimetric methos 一 a
weighing bottle method and a sorption balance method with quartz sping in
vacuum， have been constructed for measuring the moisture absorptfion and／or
desorption isotherms of the fiber specimens．
The following discussion was made for experimental results obtained．
At first， the thermodynamics of moisture sorption has been discussed from
the temperature dependence of moisture absorption isotherm for the norrnal
viscose rayon， basing on the GibbsrHermhortz equation ．relating the changes
in the total （interpal） energy，’ in’the work content （or free energy） and
in the unavailable energy （entropy）， in－the’ @water－cellulose system． Among
several deductions， the following most irnportant conclusions are obtained：
the excess energy （TAS） is greatest at the lower Values of relative humidity
， decreqses rapidly with increasing of ．relativ’ ?@humidity up to around TO％，
and further decreases．gradually up to near saturation where the excess
energy is still finite in its value． Therefore， vJater rnolecules are most
strongly attracted at low vapour pressures． The first molecules are adsorbed
on sites vvhere the attractive force is greatest and， as more molecules are
attracted， the attractive force decreases due to formation of multilayers
or clusters of the molecules with some degrees of order at least higher
than that of liquid water． The water initially adsorbed at a low relative
humidity has an excess energy ranging up to about IOO cal／g， which is rough］y
eaual to the latent heat of fusion of ice， indicating that the first water
一一 130 一
molecules 一adsorbed have degrees of orientation and association comparable
to those gf ice．
Second，， the moisture absorpt．ion ・and desorption hysteresis has been
studied． It wds thought that thiS phenomenon was due to a very ’slow attain－
rnent of equilibrium， and that absorption and desorption values would be
identical if sufficient time were allowed for the true equilibrium to be
reached． There is ample evidence now， however， that the different values do，
in fact， represent true equUibria． ln order to assure the above concept on
the true equilibria， two additional experiments have been carried out to
deduce the f6110wing conclusion that the moisture absorption and desorption
hysteresis is an unique behavior of the materials， not apparent one in non－
equilibrium， mainly caused by a dual functionality of the hydroxyl groups
bonding with each other．by hydrogen－bonds， preferentially， rather than with
water molecules under dry atmosphere in dilute concentration of water vapour，
and vice versa under wet atmosphere in saturated concentration of water
vapour．
丁hir（｛， the analyses of absσrption i．sOtherms of cellulos「c fibeγ・s in．
terms of the Brunauer， Emmet．t， and Teller’s （BET） multilayer adsorptioh
theory and Hillts therrnodynamic approach haVe been carried out． The BET
constants， vm， ．C， and nmax have been discussed with the constitution and
microcrystalline structure of the cellulosic fibers． The n was found max
to be around 6 for alinost eVery cellulosic fibers with exception of 4 for
tri－acetate fiber and 7 for Na－carboxymethylated rayOn． The moisture regains
・ith・＝ユ・・d・max≧・・1b・th・t 90％ rel・t「・e h・midity…efoun．d・・
respectiv’@ely， to be proportional to vrn． The vrn normalized by the degree of
noncrystallinity of material could be classfied into three groups； regene－
rated cellulose fiber．s， hatural’ モ?gulose fiber．s， and acetate fibers， in
the order of descending water accessbility， possibly Validating the concept
of normalization of V．“ on the basis that the moisture sorption is mostly m
affected by the differences in chemical and physical structures in the
一 131 一
noncrystalline region o｛ the’materials． When plotting the moisture
regain with n ＝ 1 （．Langmuir’s monolayer adsorption） at 900／， relative humfi－
dity against the normali2ed vm？ there found a single curved relation
inc，ea、的i， its s］。P， i， the vう、流y ar。u，d th。 p1。t，． ?B． acet、t， fiber、
being about one－third to that for regenerated cellulose fibers． The value
of C increases rapidly with increase jn the number of hydroxyl groups per
cellobiose unit．
Finally， the structure and， consequently， the nature of the adsorbed
water have been discussed by comparing the above BET analyses of sorption
isotherms with a current study of adsorbed water on cellulose materials
by differential scanning calorimetry． 丁he following conclusions are obtained：
the adsorbed waters in the fashion of multilayer or cluster formation with
n as large as up to 6 or 7 correspond to the nonfreezing bound waters；
the adsorbed waters with a few addibional numbers of n up to 7 or 8
correspond to the freezing bound waters； and the sorbed free waters are
only present’ in a range of ’relative humidjti’es higher than 90％ with n larger
than 7 or 8． These cdnclusions seem to be consistent， at least qualitatively，
with those obtained in the thermodynamic consideration of moisture sorption；
i．e．， the excess energy （：TAS） is still finite， not zero， even in a range
of relative humidfities as high as around 900／，， and the free water， if any，
must be pires’р獅煤@in a range of relative humidities higher than 900／， up to
saturation， though the differential scanning calorimetry can not distfiguish
the most strongly adsorbed water with n ＝ 1 from the nonfreezing bound
waters．
．． 132 一
Acknowl edgements’
The present dissertaticn bases on the ．studies carried out by the
author at the Deparl｛nent of Practical Life Studfies， Faculty ot’ Teacher’
Ed・cati…Hy・9・U・iver・ity・f T’?≠モ??秩@Educpti…f・・m Ap酉1・1983 t・
March， 1985 under the auspiece of Professor 卜lir6michi Kawai to whom the
author wishes to express his sincere gratitude．
The author wishes to express his sincbre thanks to Professor Kaoru
Sumiyoshi， Departrnent of Practical Life Studies， Faculty of Teacher
Education， Hyogo University of Teacher Education， for his encouragement
through the course of this work．
Thanks are also due to Associate Professor Hisashi Odani， lnstitute
for Chemical Research， Kyoto University， for his enthusiastic dfiscussion
and guidance through the course of this study on the moisture sorption
of polymeric materials．
The test sipecimens were furnished from Several companies， Toyo一一bo，
Kane－bo， Unitica， Asahi ChemiCal lndustri．es， “4itsubishi Rayons and’Daicell
Chemical lndustries， to whom the author expresses hl’s cordi’al thanks．
The physical characterization of the test specimens were performecl
by D・・T・・hihik・Ohta・Analyses Cete「r丁oy。一b・Co・・t・wh・・the auth・・
also expresses his cordial thanks．
A part of this study was supported by a scientific grant through the
Descente Foundation for Promotion of Sports Sc・ience．
