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MOLECULAR TRANSPORT OFORGANIC LIQUIDS THROUGHPOLYMER FILMSTejraj M. Aminabhavi a , U. ShanthamurthyAithal a & Shyam S. Shukla ba Department of Chemistry , KarnatakUniversity , Dharwad, 580003, Indiab Department of Chemistry , Lamar University ,Beaumont, Texas, 77710Published online: 05 Dec 2006.
To cite this article: Tejraj M. Aminabhavi , U. Shanthamurthy Aithal & Shyam S.Shukla (1989) MOLECULAR TRANSPORT OF ORGANIC LIQUIDS THROUGH POLYMERFILMS, Journal of Macromolecular Science, Part C: Polymer Reviews, 29:2-3,319-363, DOI: 10.1080/07366578908055173
To link to this article: http://dx.doi.org/10.1080/07366578908055173
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JMS-REV. MACROMOL. CHEM. PHYS., C29(2 & 3), 319-363 (1989)
Molecular Transport of Organic Liquids through Polymer Films
TEJRAJ M. AMINABHAVI" and U . SHANTHAMURTHY AITHAL Department of Chemistry K arnat ak University Dharwad 580003, India
SHYAM S. SHUKLA Department of Chemistry Lamar University Beaumont, Texas 77710
1. INTRODUCTION. . . . , . . . . . . . . . . . . . . .320 11. LITERATURE FINDINGS . . . . . . . . . . . . . . . .321
A. Vinyl Polymer Films . . . . . . . . . . . , . . . . 321 B. Rubbery Films . . . . . . . . . . . . . . . . . .337 C. Polyurethane Films . . . . . . . . . . . . . . . .342 D . Miscellaneous Polymer Films . . . . . . . . . . . .344
111. CONCLUSIONS . . . . . . . . . . . . . . . . . . . .356 REFERENCES . . . . , . . . . . . . . . . . . . . . .357
*To whom correspondence should be addressed.
31 9
Copyright 0 1989 by Marcel Dekker, Inc.
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320 AMINABHAVI. AITHAL. AND SHUKLA
I . INTRODUCTION
The molecular transport of small molecules through polymer films has been the subject of active research over almost three decades [ 1- 81. The main thrust in this area is either to ac- cumulate a large body of experimental data to assess the sta- bility of polymer films for extreme serviceability or to develop new theories which describe the phenomenology of transport processes, the latter often being studied in terms of three i m - portant parameters: permeation, diffusion, and solubility, in addition to the swelling phenomenon.
One of the latest important applications of transport phe- nomenon in industry is in the treatment of hazardous wastes which have become a serious threat to ecology and the environ- ment [ 91 . In chemical industries, however, organic compounds have been Separated on a large scale by distillation or recrystal- lization techniques which can consume much heat energy. On the other hand, separation carried out by membranes is one of the most promising achievements of energy- solving technology. Membrane separation techniques have already been used in such industrial applications as desalination of brine, salt manu- facturing from seawater, and oxygen-enriched air [ lo ] . It is thus possible to separate azeotropic mixtures as well. in the so- called pervaporation technique, the permeate is removed from the mixture at the opposite side of the membrane as a vapor [11, 121. This method selectively separates organic liquids from their mixtures.
important in several engineering applications. Contrary to gases, which diffuse through polymeric materials with little interaction, the transfer of liquids causes polymers to swell; the extent of swelling depends upon thermal conditions, chem- ical nature, degree of crosslinking, and molar mass of the polymer in addition to the nature of the penetrant, The pene- trant transport in glassy polymers will be discussed only peri- pherally, mechanism is associated with transition from the glassy to the rubbery state. and behind the penetration front separating the inner glassy core from the outer rubbery layer. Such relaxations are in- deed controlling factors of the transport mechanism [13, 141.
In this review we focus our attention on a discussion of the literature results of organic liquid (penetrant)-polymer film systems. The data base covers the period from 1970 through mid-1988. interesting data on transport (permeation, diffusion, and
The transport of organic liquids in polymer films is thus
From such studies it is known that the transport
Macromolecular relaxations are observed at
The review focuses mainly on typical and
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MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 32 1
solubility) of organic liquids (but not to a great extent on vapors and gases) and by no means it is exhaustive. Thus, only important findings are included, with occasional references to the older literature wherever necessary. Furthermore, no theoretical details are covered and thus we restrict this review to a discussion of experimental data. It is beyond the scope of any authoritative review to include all of the published results, but efforts are made here to compile and discuss those data which have great relevance in materials science, engineering, and allied areas.
I I . LITERATURE FINDINGS
The most common 3iquids used in such studies include alco- hols, aromatics substituted aromatics, aliphatics , halosubsti- tuted compounds, etc. the majority of the cases, but other commercially important aromatic polymers and rubbery films have also been investigated in a few cases. Highly aggressive polar solvents like dimethyl- sulfoxide, dimethylformamide, acetone, etc. usually showed strong interactions, leading sometimes to breaking down of the polymer structure after prolonged exposure. variations in property- structure systems have been studied. Due to the large diversity of published data, we will discuss each class of membranes separately.
Vinyl polymers have been employed in
Thus, large
A. Vinyl Polymer Films
One of the most widely studied polymer membranes in this class of polymers is polyethylenes. Both high-density (HDPE) and low-density polyethylenes (LDPE) have been used.
Recently, Gupta and Sefton used integral methods to solve equations in an iterative fashion by assuming constancy of dif- fusivity with concentration for transport of the carbon tetra- chloride-LDPE system [15]. The solution was then used in a curve- fitting procedure to estimate the concentration dependence of the diffusion coefficient (D) . The experimental concentration profiles of CCl in LDPE were also measured at 4OoC by elec-
tron microprobe analysis and energy dispersive x-ray spectro- scopy (EDAX). The value of D at 4OoC was about 6.5-7.0 X
10 cm I s . Gupta and Sefton also studied the sorption of CC14 in LDPE pellets at temperatures between 40 and 7OoC and
4
- 7 2
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322 AMINABHAVI, AITHAL, AND SHUKLA
suggested a diffusivity-concentration relationship at high con- centrations [16]. features characteristic of pseudo-Fickian behavior, which was attributed to clustering of the penetrant at the high vapor activity corresponding to this temperature.
An experimental method was used to study the concentra- tion profiles of liquids by permeation, in which the formation of an adhesive liquid film leading to erroneous results is elimi- nated [17]. The systems used in this study were m- and p-xylenes and mixed xylenes in polyethylene films. A gas chromatographic method was found to be unsuitable to measure D for CC14 in polyethylene film due to the difficulties involved
in the determination of the effective film thickness wherein mass transfer takes place [18].
For sorption of toluene i n LDPE and HDPE films, it was found that the presence of a fluorinated surface layer on the membrane reduced the initial solvent permeation rates, but the enhanced barrier property w a s lost when irreversible morpho- logical changes occurred during polymer swelling [19]. This type of temporary reduction in permeability was attributed to a combination of chemical and morphological factors. However, crosslinking of surface macromolecules did not show any signifi- cant effect. Surface fluorination of polyethylene with elemental fluorine was also reported earlier to be effective in decreasing the permeation rate of organic liquids in polymers [ 20- 221.
have shown that the fluorinated surface reduces the rate of permeation for many organic solvents with varying dielectric constants (from 1 .8 to 47.0) 1221. These properties were re- lated to the physical and chemical properties of the solvent; for instance, solvents with a dielectric cohstant of less than and between 7 and 10 were not retained.
The diffusion of n-alkanes (from carbon numbers 12-32) have been measured by the pouch method for LDPE, HDPE , polypropylene copolymer , and polypropylene homopolymer [ 23 , 241.
preted in terms of Eyring’s transition rate theory. more, correlations were attempted between the activation energy, the heat of vaporization, and the Arrhenius exponential factors. Such correlations proved useful in predicting D of n-alkanes with carbon numbers larger than 32. calculated from experimentally determined permeation (P) and solubility (S) constants of n-alkanes (from carbon numbers 12-32) for various polyolefins are given in Table 1. data show that the use of hexane (nonpolar) and methanol
The sorption curve at 7OoC displayed
The solvent barrier properties of fluorinated polyethylene
The energy of activation (E ) for diffusion was inter-
Further- D
Diffusion coefficients as
These
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TA
BL
E I
Dif
fusi
on C
oeff
icie
nts
of
n-A
lkan
es a
t 23OC f
or L
DP
E,
HD
PE ,
Pol
ypro
pyle
ne C
opol
ymer
and
P
olyp
ropy
lene
Hom
opol
ymer
Alk
anes
Dis
solv
ed i
n M
etha
nol,
Eth
anol
, A
ceto
ne,
and
Hex
ane
[ 23, 241
2 D x
lo1'
cm
/s f
or d
iffe
ren
t va
lues
of
nc
Pol
ymer
- so
lven
t sy
stem
12
14
16
18
20
22
24
26
28
30
32
Met
hano
l:
LD
PE
HD
PE
PP
-cop
a
PP
-hom
o b
Eth
anol
:
LD
PE
HD
PE
a
PP- h
omo
PP
- cop
b
Ace
tone
:
LD P
E
HD
PE
27.0
6.4
1.1
0.6
34.0
5.6
0.5
0.5
97.0
19.0
25.0
4. 9
0.8
0. 4
18.0
3.1
0.4
0.3
65.0
13.0
15.0
2.9
0.7
0.4
14.0
2.1
0.3
0.3
54.0
9.1
12.0
4.7
1.9
0.9
0.7
0.6
0.3
0.3
10.0
8. 3
4.6
1.4
0.8
0.3
0.3
0.3
0.3
0.3
0. 3
0. 3
37.0
22.0
13.0
6.2
3.3
1.3
rl 1 W
N
W
(con
tinu
ed)
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TAB
LE 1
(con
tinu
ed)
2 C
D
x lo
lo c
m /
s fo
r di
ffer
ent
valu
es o
f n
Poly
mer
- so
lven
t sy
stem
12
14
16
18
20
22
24
26
28
30
32
Ace
tone
(co
ntin
ued)
: 14.0
11.0
9.1
8.0
7. 8
6.5
12.5
10.0
8.6
7.5
7.3
6.6
a
PP- hom
o
PP- c
op b
Hex
ane:
LDPE
1300.0 1000.0
820.0
600.0
400.0
240.0
150.0
81.0
54.0
29.0
11.0
HD
PE
380.0
320.0
190.0
116.0
50.0
20.0
15.0
8.5
4.6
2.6
1.2
2400.0 2200.0 2200.0 2300.0 2000.0 1500.0 1400.0 1300.0 1000.0
770.0
430.0
PP- c
op
3400.0 2800.0 2500.0 2100.0 1700.0 1300.0 1000.0
720.0
690.0
540.0
390.
0
a
PP- h
omo b
aPp-
cop
= p
olyp
ropy
lene
cop
olym
er.
bPP
- hom
o =
poly
prop
ylen
e ho
mop
olym
er.
C n
= nu
mbe
r of
car
bon
atom
s.
W
N
c D I
> m 5 D
Z 0
in I
c
x 5
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MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 325
(polar) resulted in the ability of the polymer to swell, as reflected by a change in D values. The temperature dependence of D of alkanes in LDPE was found to exhibit an Arrhenius-type behavior in the 6 to 4OoC temperature region. (see data given in Table 2 ) . This trend was also reported earlier [ 251.
The diffusivity of dicumyl peroxide (DICUP) in annealed LDPE at 125OC resulted in increased crystallinity and decreased
DICUP diffusivity ( 3 . 2 x l oe7 cm / s ) for as-supplied pellets to
5 . 2 x cm /s for annealed and slowly cooled pellets 1261. Quenching the annealed pellet reduced the increase in crystal- linity and the corresponding decrease in D (see Table 3) .
Transport of methanol through a copolymer membrane of
polyethylene (d = 0 . 9 2 g/cm ) and poly(viny1 acetate) possessing a linear gradient of composition from one surface to the other proceeded at a slightly greater rate against the gradient of grafted poly(viny1 acetate) than along the gradient [27 ] . It was shown that incorporation of polyester in packaging films such as polyethylene or polypropylene reduces their perme- ability to organic vapors like decane, 1- heptane, toluene, and ethanol [28] .
The S and D of toluene in isotropic and oriented linear polyethylene were studied at 3OoC 1291. The sorbed con- centration in the amorphous phase was less affected by crystallinity, indicating that the free volume fraction is roughly the same for all isotropic samples. Peterlin and coworkers also studied the effect of orientation by determining the D and S of methylene chloride in drawn-HDPE films [ 301, branched low- density polyethylene (BLDPE) 131, 321, and linear low-density polyethylene (LLDPE) [33 ] . The sorption and diffusion coeffi- cient in BLDPE also decreased with increasing orientation.
A dynamic absorption technique was employed to determine the solubility of benzene, hexane, and heptane in modified polyethylene films [34 ] . Films were modified by solvent anneal- ing, crosslinking, and combinations thereof. Solvent annealing increased the solubility while crosslinking led to a decrease. The effect of combined treatment on solubility was dependent on the sequence of treatment, swelling power of the condition- ing agent, and the irradiation dose. However, the solubility of various vapors in crosslinked films varied linearly with the temperature, but some vapors in the conditioned films showed maxima with respect to temperature. explained in terms of the relative changes in the molecular volume of the diffusant and of the segmental mobility of the network chains under various experimental conditions.
2
2
3
These changes i n S were
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326 AMINABHAVI, AITHAL, AND SHUKLA
TABLE 2
Activation Energies of Diffusion ( E ) for Alkanes in
Swollen (hexane solvent) and Nonswollen (ethanol solvent) in LDPE [23]
D
ED (kcalhol)
Alkanes with n carbon atoms Hexane Ethanol
1 2
14
16
18
20
22
24
26
28
30
32
1 3 . 6 5
1 4 . 3 0
1 5 . 0 0
1 5 . 6 5
1 6 . 4 2
1 7 . 3 5
1 9 . 1 3
20 ,oo
2 1 . 9 4
24 .32
25 .69
1 8 . 0 3
1 7 . 6 1
1 8 . 6 4
1 9 . 5 5
21 .00
22 .59
The values of concentration-independent diffusivity (D ) c =o and the free volume parameters of Fujita’s theory were mea- sured for benzene, hexane, and heptane in modified polyethy- lene films using an unsteady-state absorption technique 1351. Films were modified by y-irradiation, solvent conditioning, and
dropped with ir- post- and preirradiation conditioning.
radiation, the drop being larger for the larger diffusing mole- cules.
link density was proposed. Solvent conditioning led to an in- crease in D c =o power of the conditioning agent in addition to the molecular size of the diffusing molecule. In most cases, combined treat- ment resulted in an increase in D the extent of which was
dependent upon the relative effect of the swellant and the
Dc=o
A relationship for the dependence of D on the cross- C =O
and is directly proportional to the swelling
c=O’
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MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 327
TABLE 3
Effect of Thermal Diffusivity and Equilibrium Uptake of DICUP in LDPE at 125OC [26]
8 D x 10
Heat treatment of LDPE (cm /s) 2
_ _ ~ ~ ~
As-supplied pellet 32.0
Annealed and slowly cooled 5.2
9.4 Annealed and quenched in liquid N
Annealed and quenched in ice-cold H 0 (%O°C) 7.2
Annealed and quenched in liquid N 2 and maintained
Annealed and quenched in ice-cold water and
2
2
at ambient temperature 9.1
maintained at ambient temperature 7.2
irradiation dose. In all cases, postirradiation conditioning led to values of Dc=O higher than those obtained by preirradiation
conditioning. creased with irradiation, showing a marked drop when the dose was of small effect.
D and S of hydroxy components in polyolefins were mea- sured by a permeation method [36]. explained by Eyring's rate transition theory. However, phenols did not show such a relationship, but the values of D decreased with increasing molecular weight of the penetrants. The shielded phenols exhibited D values which are greater than those of the unshielded phenols. hols exhibited linear functions of their carbon numbers. D values measured in this study were applicable to food materials which do not swell the polymer (e.g., aqueous, alcoholic, and acidic foods). These data are summarized in Table 4.
Some research activity has taken place on the permselec- tivity behavior of polyolefins. In this regard, the permea- tion characteristics and separation behavior of binary liquid mixtures of homologous series from n-pentane to n- nonane and various aromatic and cyclic hydrocarbons through LDPE mem- branes were studied [ 371. The mixtures were passed through a 1-mil thick polyethylene membrane in the temperature range of 25- 45OC.
The fractional free volume of the polymer de-
The diffusion pattern was
The log S data of the alco-
The temperature dependence of the permeation
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328 AMINABHAVI, AITHAL, AND SHUKLA
TABLE 4
Diffusion, Solubility, and Permeation Coeff ic ients of Alcohols, Phenols , and Ant ioxidants in LDPE at
23OC (compounds d isso lved in ethanol) [36]
1 0 P x 1o1O lo (g solvent/ 2 Compound (cm /s) g polymer) (cm / s )
Methanol
H ep t anol
Nonanol
Dodecanol
Te t radecanol
Hexadecanol
Octadecanol
Phenol
p-Cresol
2,4,6- Trimethylp henol
2,3,5,6-Tetramethylphenol
2,4-Di- t -butylphenol
2,6-Di- t -bu ty lphenol
2,6-Di- t -bu ty l - 4-methylphenol
3,5-Di- t - butyl- 4- h y d r o x y - benzdc acid- (2,4-di- t -bu ty lpheny1)es te r ( T i n u v u i n 120)
2- (2-Hydroxy- 3- t -bu ty l - 5-methyl- phenyl) - 5-chlorbenztr iazol (Tinuvin 326)
l , l J 3 - T r i s ( 2 - m e t h y l - 4- hydroxy-
480
55
40
11
8.2
6.4
4.8
45
23
23
16
1.2
9 .8
6.6
0.18
2.0
5- t -buty lpheny1)butane (Topanol) 0.054
0.0047 0.26
0.021 0 .23
0.029 0.23
0.033 0.21
0.053 0.25
0.0026 0.12
0.0056 0.13
0.019 0.44
0.03 0.48
0.016 0.02
0.13 1.30
0.19 1.25
0.045 0.008
0.71 1.40
0.00031 0.00002
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MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 32 9
rate for both pure liquids and their mixtures exhibited an Arrhenius behavior, and the separation efficiency varied in- versely with the temperature. The energy of activation for permeation ( E ) was observed to be 16-22 kcal/mol €or both
P pure liquids and binary mixtures of benzene, hexane, cyclo- hexane , and 2 , 2 - dimethylbutane. Permeation rates were af- fected both by the hydrocarbon polarity and solubility. mixtures permeated faster than either of the pure components, with maximum permeation rates occurring at about 50 wt% mix- tures for benzene + n-hexane and benzene + cyclohexane sys- tems. plasticizing and solubility effect.
hexane , and their mixtures have been investigated for poly(viny1 alcohol)-poly(viny1 acetate) composite porous membranes [ 381. Neither swelling nor shrinkage with these membranes w a s ob- served. meated quickly while benzene permeated very slowly. For the binary mixtures of toluene, isopropyl alcohol, 0- xylene , iso- butyl alcohol, n-hexane, and n-octane, the rate of permeation through polyethylene membranes and the selectivity in separat- ing the mixtures decreased with increasing pressure on the membrane [ 391. For dcohol- hydrocarbon mixtures, a concen- tration dependence was observed, which led to an increased rate of alcohol permeation with increasing pressure. In such mixtures the hydrocarbon selectivity decreased with increasing pressure and with increasing hydrocarbon content in the mix- ture. A solution-diffusion model was used to study the per- meation of the m-xylene /p-xylene mixture under high pressure for polyethylene film wherein P was found to depend on the mixture composition [ 401. These results were interpreted qualitatively using the free volume model. of different hydrocarbons as permeants, the effect of tempera- ture variation on the rate and selectivity of liquid permeation through polyethylene membranes was studied [ 411. Under constant pressure the rate of permeation increased with increas- ing temperature whereas permselectivity decreased up to a certain value of the permeant pressure starting from zero pressure, beyond which it further increased.
The permeabilities of polyethylene film to a number of organic vapors at 21 , 38, and 49OC were measured by a sorp- tion method [421 . P was calculated from the steady-state rate of the weight gain and was predicted by correlating the Hilde- brand solubility parameters using the E data from permeation
experiments.
Several
These results were explained by a combined internal
Permeation characteristics of benzene, n- hexane, cyclo-
It was found that n-hexane and cyclohexane per-
By using azeotropes
P Permeation of T-labeled toluene through
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330 AMINABHAVI, AITHAL, AND SHUKLA
polyethylene films fully swollen with chlorobenzene , mesitylene , cumene, toluene, ethylbenzene, cyclohexane , tetralin , and decalin has been determined [ 431. The results exhibited an Arrhenius temperature dependence over the temperature interval of 25 to 4OOC. The permeation was enhanced by increasing solubility of the swelling agent in the film. The values of P measured at 25OC were in the range of 2.09 to 0 . 5 1 x
cm Is. The measured E values were in the range of 1 1 . 4 1 to
16 .68 kcal/mol. small organic penetrants in polyolefins were described by Durning et al. [44 ] .
HDPE , elasticized polyolefin , and polychloroprene membranes were recently measured at 22 and 5OoC by using the immersion/ weight gain method and by permeation cell experiments 145, 463. Some relevant data on thickness- dependent permeation rates and diffusivity are summarized in Table 5. and McLeod are summarized in Table 6 wherein polyethylene results are compared with several rubbery materials [47].
lene films toward organic liquids and vapors were also examined L481. and transport properties was determined to establish the struc- ture-property relations for membrane permeation. used in this study included isooctane, methyl cyclohexane, toluene, p-xylene, and o-xylene. The film was solvent modi- fied by immersing it in solvent baths at 60-lOO0C for 24 h , and samples were dried in vacuo at 4OOC. Liquid permeation fluxes were determined by using a permeation cell in a thermo- statted air bath. The kinetics of vapor sorption were deter- mined by using a quartz spring balance at constant tempera- ture by admitting vapor to the evacuated sorption column at saturated vapor pressure and determining the spring displace- ment. These measurements were used to determine P , S, D , and selectivity in treated and untreated films. The films were more selective toward toluene than to isooctane, and p-xylene than 0- xylene. Annealed films showed enhanced permeability but reduced selectivity.
A pouch method was used to study the permeation of ben- zene, carbon tetrachloride, ethyl alcohol, and ethyl acetate in polyethylene, polystyrene, Saran, cellulose acetate, and sili- cone rubber [ 491. The permeability increased linearly with increasing similarity between components; also, similarity in electric properties exhibited a profound effect.
2 P
The differential sorption and permeation of
Permeabilities and diffusivities of some organic solvents in
The data of Weeks
The permeation and permselective properties of polypropy-
The effect of thermal treatment on the film morphology
The solvents
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TA
BL
E 5
Per
mea
bilit
y an
d D
iffu
sivi
ty D
ata
of O
rgan
ic L
iqui
ds
thro
ugh
HD
PE M
embr
anes
145, 461
r c, D
0
v,
W w,
Liq
uid
4
(mil)
("
C)
(cm
/h
)
D x
10
2 T
hick
ness
T
empe
ratu
re
Per
mea
tion
rat
e 2
3 (g
/cm
/h
) x
10
Ben
zene
Tol
uene
~~
~
1 ,l
,2- T
rich
loro
etha
ne
30
22
0.51
9. 4
1.4
100
50
3.00
1.5
1,2-
Dic
hlor
oeth
ane
30
22
0.81
1.3
2.2
100
50
4.10
18.0
-
60
22
-
60
22
Sty
ren
e 30
22
1.80
11.0
1.1
100
50
6.00
17.0
30
22
1.50
12.0
1.2
60
22
100
50
13.00
17.0
30
22
2.60
13.0
1.2
60
22
100
50
15.00
18. 0
-
60
22
-
-
-I
A D
z
v,
-0 0
A
-I % 0
7J
0
D
Z 0 -
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332 AMINABHAVI, AITHAL, A N D SHUKLA
TABLE 6
Benzene Diffusivities for Protective Garment Materials [ 471
Polymer
6 D x 10 2 Thickness
( m i l ) (cm bin)
Homogeneous, nonbonded materials:
Butyl rubber
Natural rubber latex
Neoprene rubber latex
Nitrile rubber latex
Polyethylene (medium density)
Surgical rubber latex
Teflon
Coated /bonded materials:
Butyl-coated nylon
0.14 Ethylene vinyl acetate + 0.86 polyester substrate
Polyethylene- coated
7
18
25
1 4
1
9
2
1 5
9
5
2 . 6
6 9 7 . 0
34 .0
21.0
> O . 5
87.0
0 . 4
32.0
116.0 -
1 5 . 0
53 .0
Tyvek (polyethylene toward water) - Tyvek toward water - Poly(viny1 alcohol) 9 44.0
Saranex 15 3 1.0
The effect of the degree of crosslinking of glassy polymers on the transport mechanism of cyclohexane w a s investigated by Peppas and coworkers using a series of divinylbenzene (DVB )-crosslinked polystyrenes having crosslinking ratios (X) ranging from 0.00138 to 0.060 mol DVB /mol styrene [ 50-521. Dynamic swelling experiments with cyclohexane at 3OoC showed an anomalous transport mechanism. An overshoot in the pene- trant uptake was attributed to macromolecular relaxations. Crack formation in DVB-crosslinked polystyrene samples swollen by cyclohexane was also studied as a function of time, temperature, degree of crosslinking, and sample thickness [ 511.
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MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 333
Dynamic swelling experiments were performed at 20, 30, 40, and 5OOC. attributed to stress effects in the presence of a good solvent. In another study the transport of cyclohexane through well- characterized, glassy, crosslinked polystyrene films at 20 , 30, 40, and 5OoC [52] was investigated. These results were then
analyzed using the relation M /M, = kt , which represents the frac-
tional uptake, and interpreted in terms of competitive relaxational and diffusional mechanisms.
anomalous transport of cyclohexane in crosslinked polystyrene samples is affected by the degree of crosslinking. The trans- port is characterized by an overshoot in the dynamic cyclo- hexane uptake, which depends on the relative ratio of diffu- sional and relaxational times. Solvent crazing was induced at low crosslink densities due to relatively high swelling stresses in the gel region.
Diffusion of cyclic hydrocarbons within benzene- swollen, polystyrene-DVB gel-type beads was studied at 25OC [ 541. The values of D as calculated from Fick‘s law of diffusion were found to depend upon the volume fraction of polymer. dependence suggests that the swollen polymer network acts as a physical obstruction to diffusion. polymer-solvent interactions affecting diffusion were the same in the solvent-swollen polymer as in the pure benzene solvent.
A very convenient and reliable gravimetric method was developed for measuring the swelling of poly(styrene-co-DVB) in particulate form [ 551. The swellability S’ (in milliliter of liquid absorbed per gram of polymer in equilibrium with excess liquid) for six styrene-co-DVB polymers with crosslink densi- ties p ranging from 0.01 to 0 . 1 2 was measured in 1 9 organic liquids. In each study of S as a function of p, the relation- ship was given by
The observed crazing in polymer samples w a s
n t
In a study by Peppas et al. [531, it was shown that
This
These data suggest that
where A = l / p is the average number of carbon atoms in the ‘’backbone” of polystyrene segments between crosslink junc- tions, C is the relative swelling power of the liquid, and po = l / h is the critical crosslink density above which S is
equal to zero. - 1
X o
0 The constants C and the corresponding p =
0 determined for 19 liquids are given in Table 7.
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334 AMINABHAVI, AITHAL, AND SHUKLA
TABLE 7 -1J3 Swelling Parameters C and (p ) for Various Liquids [55] 0
-1J3 -1J3 Liquid C (Po) = ( A o )
N , N-Dimethylaniline
C yclohexanone
Anisole
Benzene
Toluene
1.4- Dibmmo- n- butane
1,4-Dichloro-n-butane
n-B utyl bromide
n-Butyl iodide
Pyridine
Methyl- n- but yl ketone
n-Butyl chloride
n-Butyl acetate
cis-Decahydronaphthalene
trans- Decahydronaphthalene
(Trifluoromethyl) benzene
C yclohexane
n-Butyl ether
2.25
2.16
2.00
2 .14
2.02
1.82
1.78
1.73
1 .69
1.63
1.50
1 . 4 0
1.33
1 .00
0. 80
0.71
0.53
0.51
1.80
2.05
1.70
1.70
1.75
1.85
1.70
1 .66
1.95
1.72
1.80
1.70
1.60
1.85
1.80
1.85
1.95
1.50
Swelling studies on interpenetrating polymer networks of polystyrene and acrylonitrile were made with 1 0 liquids ranging
in solubility parameters ( 6 ) from 15.13 x 1 0 ( J m
(n-heptane) to 24.74 x 1 0 The results were used to compute the apparent molecular weights between crosslinks from a modified Flory-Rehner rela- tion; these results suggest that increased entanglement decreases swelling. S and D of toluene vapor at 3OoC i n polypropylene with draw ratios from 1 to 18 have been studied 1571. D
13 -3)1/2
( J m - 3)1 J 2 (benzyl alcohol) [ 561 .
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MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 335
increased exponentially with toluene concentration, but i ts con- centration dependence w a s weaker with an increased draw ratio, indicating that the severely constrained chain segments in the drawn samples have much less freedom to mix with the pene- trant molecules.
ethyl met hacrylate-co-n- vinyl- 2-pyrrolidone) was studied at 25OC. the rubbery/glassy interface during swelling was used to ob- tain useful information on penetrant transport mechanisms. Similar studies can be found in the papers of Peppas and co- workers [58, 591, as well as studies of dynamic swelling on well-characterized coal particles [SO-631. A non-Fickian or Case I1 transport was prevalent in most of these studies.
Methanol transport in crosslinked PMMA disks has been studied in the temperature range of 35- 56OC [64] . Deformed samples absorbed solvent very quickly, exhibiting Fickian dif- fusion. Undeformed samples sorbed at lower rates, and the kinetics tended toward Case I1 transport. D values for de-
- 8 2 formed samples were in the range 2-7 x 10
was about 10 kcal/mol. 2 0.5 to 3.5 x lo-* cm / s , with ED being 2 4 . 9 kcalImo1. Sorp-
tion kinetics and equilibria for methanol, ethanol, and l-pro- panol in 0.544 mm diameter PMMA microspheres were deter- mined at 35OC over a wide range of relative pressures 1651. Sorption isotherms were concave to the pressure axis at low relative pressures but showed convex behavior at higher rela- tive pressures. mechanisms were also discussed.
panol in PMMA was studied following predetermined annealing treatments of the polymer matrix [66] at 20 and 5OOC. data are given in Table 8.
Transport studies were made on polystyrene and PMMA by using a variety of organic liquids including alcohols, aliphatic hydrocarbons, and aromatic hydrocarbons wherein Case I1 transport was observed [67-711. The effects of prior thermal history on the kinetics and apparent equilibria of subsequent n- hexane sorption in monodisperse and submicrometer diameter, glassy polystyrene microspheres were studied [ 681. Repetitive sorption and desorption cycles were compared with continuous sorption and desorption experiments. The equilibrium uptake of n-hexane in preswollen samples decreased monotonically with the cumulative time under vacuum, independent of the cycle frequency or the number of sorption- desorption cycles.
Methylene chloride transport in copolymers of poly( 2- hydroxy-
The abrupt change in the penetrant concentration at
cm / s , and ED For undeformed samples, D varied from
Various aspects of the types of transport
The sorption behavior of methanol, ethanol, and n-pro-
These
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3 36 AMINABHAVI, AITHAL, AND SHUKLA
TABLE 8
Diffusion Coefficients and Activation Energies [ 661 -
7 2 D x 1 0 (cm / s )
Liquid 20% 5OoC (kJ /moll ED
Methanol 4 . 6 7.6 13.6
Ethanol 2.2 5.0 21.8
n- Propanol 1 . 3 2 .9 21.8
Diffusion of organic solvents into glassy polymers often results in a phase transformation of the hard, solid polymer into a swollen, rubbery material [72 ] . During sorption, in- ternal stresses that exist in the swollen and glassy parts of the polymer are thought to contribute significantly to the "anomalous" diffusion. tion data for the methanol-PMMA system were obtained on films ranging in thickness f r o m 1 / 3 2 to 1/4 in. The results showed features characteristic of both a strain-dependent D and of a stress gradient contribution to the mass flux. An attempt to reproduce these results by combining a strain-de- pendent diffusion model with a stress-induced contribution to the flux was presented.
The transport kinetics and equilibrium concentrations of n-pentane at high penetrant activities in annealed poly- styrene were determined and compared with similar measure- ments in biaxially oriented polystyrene [73--751. The rate of Case I1 sorption in biaxially oriented polystyrene was about three-to-four times faster than the sorption rate in an- nealed polystyrene. oriented polystyrene was more highly temperature- dependent than in the cast-annealed film. The observed higher activa- tion energies coupled with the larger relaxation- controlled sorp- tion rates in biaxially oriented polystyrene suggest the involve- ment of larger polymer segments in the rate-controlling polymer relaxations. Solvent crazing as a function of thermodynamic interaction of the penetrant was also investigated [ 73-75]. However, in another study [76] the S, P , and D of methanol in PMMA were investigated at 303 and 313.8 K . The value of -AH, was about - 4 . 2 kJ/mol, whereas P was 0.15 and 0.12 X
In this investigation, isothermal sorp-
The Case I1 sorption process in biaxially
- 10 7"cm3-cm/cm2*s*cmHg, and D was 0.039 and 0.093 x l o w 7
cm / s , respectively. 2
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MOLECULAR TRANSPORT O F ORGANIC LIQUIDS 337
B. Rubbery Films
In a study by Southern and Thomas [ 7 7 , 781 concerning the diffusion of various liquids in natural rubber vulcanizates and synthetic elastomers, it w a s shown that neither the amount of carbon black filler nor the degree of crosslinking of the rubber had a significant effect on D. These results are given in Table 9. Later, Blow et al. found that the penetration rate of acetone in fluorocarbon rubber vulcanizate is related to the film geometry, morphology, and orientation 1791. D of methylene chloride, chloroform, benzene, and 2,2,4- trimethylpentane in 1,4-polybutadiene having trans contents between 2 and 100% was obtained from vapor sorption and desorption kinetics [ 801. For amorphous polymers (trans content less than 70 to 80%) the DcZ0 and E
with increasing size of the diffusant. 80%, a sudden decrease in D and in the equilibrium vapor sorp- tion occurred, which was accompanied by a large increase in the concentration dependence of D. These changes are due to the onset of crystallinity, but the absence of any sudden change in ED suggests that the main effect is geometric due to
the inaccessibility of the crystalline regions which have less change in the basic mechanism of diffusion than the amorphous regions. Variations in crystallinity produced by different heat treatments give the expected variations in D and equilibrium vapor sorption.
rubber vulcanizate (2- chloro- 1,3- butadiene) , based on different carbon-black types and bondings, was studied by Lawandy and Helaly [ 811. crease in carbon- black loadings. Particle size and aggregate structures of carbon black showed erratic results, This w a s attributed to the wrinkles formed at the rubber surface under high equilibrium swelling rates. The data are given in Table 10. Earlier, i t was shown that at a high swelling ratio, rubber surfaces showed several wrinkles for samples contdning rela- tively large carbon-black particles [82, 831. These wrinkles reduce the rate of penetration of the solvent in the rubber. Also , D of some organic liquids increased with an increase in chemical crosslinks in the matrix, although the opposite seems to be logical. same cohesive energy densities possess higher swelling values 1841.
The effects of mixtures of methanol, ethanol. and methyl- t-butyl ether in gasoline on the properties of commercial elastomers were studied by Abu-Isa 185, 861. An unexpectedly
decreased with increasing trans content and D A t trans contents above
The penetration rate (Q) of chloroform in chloroprene
The results showed an increase in Q with an in-
It is noted that solvents and polymers of the
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338 AMINABHAVI, AITHAL, AND SHUKLA
TABLE 9
Diffusion Coefficients of Various Liquids in Natural Rubber at 25OC 177, 781
Liquid
Acetone
Amy1 alcohol
Aniline
Benzene
Carbon tetrachloride
C yclohexane
Decane
Diethyl ether
Dodecane
Ethyl acetate
Hexadecane
n- Hexane
Methyl ethyl ketone
Nitrobenzene
Nonane
Tetradecane
Toluene
55.0
7 . 6
8 . 2
71.0
47.0
39.0
35.0
100.0
22.0
66.0
14.0
70.0
57.0
16.0
56.0
15.0
85.0
high swelling of the fluorocarbon elastomer in methanol w a s ob- served. This behavior was explained by using the solubility parameter concept. Recently, Myers and Abu-Isa examined the swelling behavior of the fluoroelastorner (at various tempera- tures) to methanol and mixtures of methanol and polar and non- polar solvents “1. In these studies, NMR was used to corre- late the swelling behavior with the structure of methanol.
rubber was studied in the interval of 25 to 6OoC [ 881. The results, given in Table 11, suggest that absorption of methanol
Sorption, permeation, and diffusion of methanol in natural
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TABLE 1
0
Pen
etra
tion
Rat
es a
nd D
iffu
sion
Coe
ffic
ient
s of
Car
bon-
Bla
ck-L
oade
d C
hlor
opre
ne P
olym
er [
811
SA
F (
20)
a
MT
(470
) S
RF
(60
) H
AF
(24)
C
arbo
n
Q
x 1
0
DX
lO
Q
x
10
D
Xl
O
Q
x 1
0
Dx
lO
bl
ack
'I2)
(cm
/s
) (p
hr)
(c
m/s
1'2)
(c
m 2
/s)
(cm
/s 'I2
) (e
m
/s)
(cm
/s1'
2)
(cm
/s
) (c
m/s
lo
adin
g 7
7 7
7 Q
x
lo4
D x
10
2 2
2
10
8.
1 5.
16
5.9
2.75
8.
3 5.
42
8.7
5.96
20
8.8
6.09
6.
8 3.
65
9.7
7.41
8.
3
5.42
40
10.6
8.
84
7.5
4.43
12
.4
12.1
9.
9 7.
71
60
13.1
13
.51
8. 9
6.
23
16.2
20
.65
11.6
10
.59
a
furn
ace.
N
umbe
rs i
n p
aren
thes
es r
epre
sent
par
ticl
e si
ze.
MT =
the
rmal
med
ium
. SR
F =
sem
irei
nfor
cing
H
AF
= high
abra
sion
fur
nace
.
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TAB
LE 11
Tra
nspo
rt D
ata
for
Met
hano
l-N
atur
al
Rub
ber
Sys
tem
s [ 881
S P
lo7
a ED
Ea
P
(kJ/
mol
) (k
J/m
ol)
(kJ/
mol
)
10
a D
x 10
2
(OC
) em
’* cm
H g
] cm
- g
cmH
g]
(m
1s)
3 [e
m (S
TP)*
cm/
3 [e
m
(ST
PI/
T
empe
ratu
re
26
35
50
60
0.278
0.213
0.137
0.105
1.50
0.53
1.86
0.87
2.57
1.80
- 28.0
18.0
54.0
3.19
3.00
?Eva
luat
ed from
the
Arr
heni
us r
elat
ion.
1: 0
I D I
z D m I
D - 5 >
-I I
D
r
D z
U
v, I
c
x
r
D -
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MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 341
in natural rubber is smaller than for silicone rubber. The in- crease in P at higher relative pressures was attributed to some degree of plasticization compatible with the selectively high up- take of penetrant in the region. Furthermore, the data indi- cate a significant degree of clustering with immobilization. However, no indication of Langmuir- type sorption occurred at low relative pressures.
The swelling of thermally stable networks of styrene- butadiene-rubber (SBR) by an aromatic oil w a s studied from ambient temperature to 2OOOC [89] . A model based on Fick's law was developed in which a change in geometry of the elas- tomer was considered with the assumption of constant D. relevant data are given in Table 12. A theory was developed to calculate the solvent tracer D in a homogeneous swollen membrane from the measured hydraulic P [ 901. Experimental solubility data for natural rubber, butyl, butadiene, isoprene, and butadiene- styrene rubber membranes with 15 different organic liquids were obtained and analyzed by using the theory. A pulsed field gradient spin echo method was used to measure D of 10 paraffin hydrocarbons in several uncrosslinked rubbers at 51OC [ 911. Various free volume parameters were obtained from the concentration dependences to establish the diffusion mechanism of decane and hexadecane in rubbers.
A considerable body of literature exists on the penetration of protective clothing materials by various hazardous chemicals [ 92-94].
Some
These results suggest the proper use of protective
TABLE 12
Diffusion Coefficients versus Temperature of
SBR-Aromatic Oil System [ 891
8 D x 1 0 2
( O C ) (m 1s) Temperature
20 1 6 . 0
100 556.0
163
180
201
1690.0
2530.0
3390.0
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342 AMINABHAVI, A I T H A L , A N D S H U K L A
materials in such environments. The P of vapors of benzene in air was calculated from measured values of S and D for natural rubber, nitrile rubber, neoprene, a blend of natural rubber and neoprene, butyl rubber, polyvinyl chloride, and polyethylene membranes. The value of P for natural rubber
at room temperature was 4 . 2 x 10 cm / s for 1 0 ppm con-
centration of benzene vapor in air. Thus, a worker ( 1 . 8 m surface area) completely clothed in a 0 .0254 cm (10 mil) natural rubber suit would be exposed through the skin to 0 . 3 mg benzene in an 8-h shift if the benzene concentration was 1 0 ppm. centration, the worker would inhale 1600 mg benzene i f his
tidal volume was 7000 cm3, his breathing rate w a s 1 5 min-l, and he was wearing a respirator with a protection factor of 100.
Swelling experiments were used to measure the cohesive energy densities of five unsaturated polyester resins with varying degrees of crosslinks [ 951. Seventeen single solvents and 11 binary mixtures of acetone-benzene were used as permeants. The structure of three crosslinked polymers con- taining naphthalenic rings in their backbone structure was in- vestigated by dynamic swelling and thermal analytical methods [ 961. port in microparticles (40 m m ) of these polymers is non-Fickian.
ether ketone), PEEK, was investigated as a function of tem- perature, sample thickness, surface treatment, and thermal history [ 961. The solubility of methylene chloride in neat PEEK was 23 wt% and is independent of the thickness. Both surface treatment and thermal annealing affected the penetra- tion rate, but the bulk solubility was independent of surface treatment. The sorption and desorption processes were quite different, and the diffusion was not described by a simple Fickian Case I. gested a two- step relaxation controlled diffusion mechanism.
-10 2
2
In the same time period and with the same benzene con-
It was found that pyridine and n-propylamine trans-
The sorption of methylene chloride in neat poly(ary1ether
The penetrant movement of a sharp front sug-
C. Polyurethane Fi lms
Transport studies of s m a l l organic solvent molecules through polyurethane films are very interesting in that the latter com- prises hard and soft segments, thereby controlling the mech- anism of transport in a very peculiar manner. studies can be found in the literature.
adipate glycol, 4,4'- diphenylmet hane diisocyanate , 1 ,4- butanediol ,
Only a few
A number of polyurethanes were prepared from polyethylene
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MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 343
and 3,3'-diChlOrO- 4,4'-diaminodiphenylmethane, and the tempera- ture dependence of swelling properties with nitrobenzene was determined [ 971. These data suggest that microphase separa- tion influences the swelling properties so that information about the extent and perfection of microphase separation can be ob- tained. The rate of absorption of benzene by open-cell poly- urethane foams of varying pore size (30- 85 poreslin. ) was de- pendent on the size of the foam samples [ 9 8 ] . Mass transport from the bulk vapor to the matrix surface exerted a more sig- nificant resistance than did the rate of diffusion in the matrix itself. Even though these foams have a large permeability to air at low pressures, pore diffusion appears to be more signifi- cant than bulk flow in describing the absorption process, re- sulting in absorption behavior which is more characteristic of closed-cell foams. process was used to estimate D and pore mass transfer coeffi- cients. Although the model w a s inadequate to describe the absorption process completely, the significance of the unex- pected pore diffusion resistance to mass transfer was quantified. While the reason for this anomalous behavior remains unknown, open-cell foams cannot be considered simply as a high-surface- area thin-walled form of the matrix material in describing the absorption process; the effect of foam size must also be considered,
a segmented polyurethane were studied to determine how the behavior is affected by the choice of solvent and the hetero- phase nature of the polymer [ 991. Immersion experiments in n-heptane liquid, a poor solvent, and incremental sorption ex- periments in n- heptane vapor showed normal Fickian behavior. With liquids of increasing polarity, such as 1-chloroheptane, three dichloroalkanes , and o-dichlorobenzene , the swelling in- creased to very high levels. weights between crosslinks ( M c ) , as computed by the Flory-
Rehner theory, varied widely with different liquids. The sorp- tion and desorption curves for the highly swelling liquids showed various anomalies, some of which might be the result of solvent-induced relaxation of hard segment domains. Some dif- fusion data are given in Table 13.
The solubility, diffusivity , thermodynamic quantities and kinetic parameters of several organic solvents in polyurethane membranes were determined by thermogravimetry [ 1001 . parameters such as activation energy of desorption, equilibrium sorption constant, changes in standard enthalpy and entropy of sorption, permeability, and activation energy of diffusion were calculated to correlate the microscopic molecular structure
A dual resistance model of the absorption
The sorption and diffusion of a series of organic liquids in
Effective values of the molecular
Kinetic
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344 AMINABHAVI, AITHAL, AND SHUKLA
TABLE 1 3
Diffusion Data of Solvents for Polyurethane Elastomer [ 991
D x 10 Molecular weight between 2 crosslinks (Mc)
Liquid (cm / s )
2- Heptane 7.3 250
1- C hloroheptane 8.4 630
1,7-Dichloroheptane 8.4 1120
1,6-Dichlorohexane 1 4 . 4 3860
1,5-Dichloropentane 17.8 1660
0- Dichlorobenzene 9.5 -
with macroscopic properties of the solvent in the polymer mem- brane [ 1001. These results, given in Table 1 4 , were inter- preted in terms of linear free energy relationships.
of a series of aliphatic alcohols in a polyurethane film at several temperatures [ l o l l . The values of D were calculated from the desorption curves during the early stages of desorp- tion. In general, D of the straight chain alcohols increased with temperature and decreased with molecular weight. The branched chain alcohols had lower D ' s than the unbranched isomers. E values were in the range of 9.16-14.5 kcal/mol
(see Table 15) . and S.
Steady- state permeation rates and equilibrium sorption measurements were made for polyurethane a s a function of temperature for a series of alcohols like methanol, ethanol, 1-propanol, R- , iso- , s- , and t-butyl alcohols, 1-pentanol, 1-hexanol, and 1-heptanol [ 1021. Calculated integral diffusivi- ties of the various penetrants correlated wel l with the effec- tive penetrant size. difference between the solubility parameters of the polymer, and penetrant D decreased for the normal alcohol series.
A thermogravimetric method was used to evaluate D and S
D P was also calculated from the values of D
S for the alcohols increased with the
D. Miscellaneous Polymer Films
Arrhenius plots for the tern per ature- dependent perm eation rates of alcohols (butanol, propanol, ethanol) through porous
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MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 345
TABLE 1 4
Diffusivity and Permeability of Organic Liquids through Polyurethane at Various Temperatures [ 1001
Temperature D x 1 0 * P x l o 8 2 2
Liquid ("C) (cm / s ) (cm / s )
Benzene
Toluene
C hlorobenzene
Hexane
Acetone
3-Methyl- 1- butanol
1- Hexanol
1- H ep tanol
1- Oc t anol
30
40
50
30
40
50
30
40
50
30
40
50
30
40
50
30
40
50
30
40
50
30
40
50
30
40
1 2 . 9
18.8
23.5
1 4 . 3
16 .0
19 .4
13.7
1 7 . 7
28.6
5.64
6.09
6.75
14. 3
19. 3
26.5
1 .40
2.97
5.58
1 .42
3.07
4.80
0.863
1 . 6 1
3.59
0.497
0.713
7.22
10 .5
1 3 . 2
6. 97
8.07
9.81
1 2 . 4
16 .4
27.2
0.465
0.528
0.631
5.51
8.42
12. 8
0.499
1.11
2.28
0.582
1 .30
2.28
0.321
0.660
1 .56
0.148
0.236
(continued)
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346 AMINABHAVI, AITHAL. AND SHUKLA
TABLE 1 4 (continued)
Liquid
D x l o 8 P x l o 8 2 (cm I s )
2 Temperature (OC) (cm I s )
1-Octanol (continued) 50 1.81 0.663
Methyl acetate 30 11.7 5.12
40 16.4 7.52
50 24. 3 1 2 . 2
Ethyl acetate 30 1 1 . 2 4.61
40 17.0 7.12
50 21.6 9.23
poly(m-phenylene) liquid crystalline trans- 4- (propyl cyclo- hexy1)benzoate ( I ) membranes showed a break at the phase transition temperature (i.e., 54OC) of (I) [ 1031. The E was dependent on the membrane structure and
the degree of ordering of the polymer. value was 36.2 kJ Imol and lower at lower degrees of orienta- tion. the end of a cylindrical rod of 25 mm diameter and 50 mm length of polycaprolactam for 36-104 h in isotopically labeled methanol [104]. tivity of methanol on the depth of its penetration into the rod of polycaprolactam had a stepwise path. Values of D
- 7 determined from two sections of the graph were 4 x 1 0
4 x cm I s . The free volume model proposed by Fujita was satisfactory for describing the diffusion of a number of organic vapors and liquids in polymers at temperatures higher than T Some polymer-penetrant systems studied are listed
in Table 16 [1051.
sion in a styrene- butadiene- styrene (SB S) triblock copolymer film, prepared from a toluene or ethyl acetate solution, was investigated in the temperature range of 40 to llO°C by using sublimative desorption techniques [ 1061 . Parallel studies on the mechanical relaxation of this copolymer were carried out in the same temperature range to be compared with the
P For butanol this
The diffusion of methanol was measured by immersing
The curves showing the dependence of ac-
and 2
9'
The temperature dependence of p - aminoazobenzene diffu-
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TA
BL
E 1
5
Tra
nspo
rt D
ata
for
Alip
hati
c A
lcoh
ols
in P
olyu
reth
ane
[ 101
1
8 ED
P x
10
8 D
x 1
0
(kca
l/m
ol)
2 S
(g s
olve
nt /
Alc
ohol
(OC)
(cm
Is
>
g p
last
ic)
(cm
/s
) 2
Tem
pera
ture
Met
hano
l 24
4.
44
0.23
36
1.04
30
5.42
0.
2400
1.
30
9.16
40
10.6
0.
2631
2.
80
Eth
anol
1 - P
ropa
nol
2-Pr
opan
ol
50
14. 3
0.
2698
3.
87
24
2.88
0.
2760
0.
7 95
30
4.20
0.
2686
1.
13
9. 93
40
6.84
0.
2786
1.
91
50
11.9
24
2.55
0.28
93
3.45
0.26
02
0.66
4
30
3.16
0.
322
1 1.
02
10.4
40
6.21
0.
3527
2.
19
50
10.4
0.
3882
4.
05
24
0. 9
70
0.21
15
0.20
5
30
2.20
0.
2356
0.
518
14.5
40
4.24
0.
2722
1.
15
50
8.09
0.
2806
2.
27
(con
tinu
ed)
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TA
BL
E 1
5 (c
onti
nued
)
Alc
ohol
S
(g
sol
vent
1 D
x
lo8
(cm
2 /s
) g
plas
tic)
T
empe
ratu
re
(OC
)
8 ED
P
x
10
2
(cm
/s
) (k
cal /
mol
l
l-B
utan
ol
2-M
ethy
l- 1
-pro
pano
l
1-P
enta
nol
1-O
ctan
ol
24
30
40
50
24
30
40
50
24
30
40
50
24
30
40
50
2.16
2.83
5.26
8.80
1.00
1.85
3.56
6.93
1.56
2.47
4.27
7.02
0.29
5
0.49
7
0.71
3
0.81
0
0.34
61
0.33
43
0.36
47
0.38
25
0.27
65
0.29
20
0.35
95
0.41
06
0.36
41
0.37
11
0.38
11
0.39
40
0.26
70
0.30
60
0.30
21
0.34
12
0.74
8
0.94
6 10
.2
1. 9
2
3.37
0.27
7
0.54
1.28
2. 8
5
0.56
8
0. 9
17
1.63
2.77
0.07
87
0.15
2 12
.1
0.21
5
0.61
8
13. 4
10.5
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TA
BL
E 1
6
Pol
ymer
-Pen
etra
nt
Sys
tem
s A
naly
zed
from
Fuj
ita'
s F
ree-
Vol
ume
The
ory
for
Dif
fusi
on [ 1
051
Pen
etra
nt
Pen
etra
nt
conc
entr
atio
n ra
ng
e T
empe
r at u
re
(vol
ume
ran
ge,
P
olym
er
frac
tio
n)
t ("
C)
Ref
eren
ce
Met
hano
l P
oly
(vin
yl
acet
ate)
0.
01-
0.09
40
13
4
Met
hano
l P
oly
(met
hyl
acry
late
) 0.
02-
0.15
15
- 65
13
5,
136
0.01
- 0.
09
40
134
Met
hyl,
P
oly(
met
hy1
acry
late
) A
ppro
xim
atel
y 15
- 65
13
5,
137
eth
yl,
0.
02-
0.15
fo
r al
l 15
- 65
n-p
rop
yl,
p
enet
ran
ts
25-
65
n-b
uty
l ac
etat
e 35
- 65
Ben
zene
P
oly
(met
hyl
acry
late
) 0.
05-
0.20
0.03
- 0.
15
Ben
zene
P
oly
(eth
yl
acry
late
) 0.
04-
0.18
Hal
otha
ne (
CF
3C
HC
lBr)
P
oly
(dim
ethy
lsil
oxan
e)
0.02
- 0.
25
30-
60
135,
13
8
25-
45
139
5-
60
135,
13
7
27-
60
140
Met
hoxy
fluo
rane
P
oly
(dim
et h
ylsi
loxa
ne)
0.02
- 0.
25
27-
60
14
1
(CH
C12
CF 2
0CH
3)
(con
tinu
ed)
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TAB
LE
16 (
cont
inue
d)
Pen
etra
nt
Pen
etra
nt
conc
entr
atio
n ra
nge
Tem
per a
t ure
(v
olum
e)
ran
ge,
P
olym
er
frac
tion
) t
(QC
) R
efer
ence
C yc
lopr
opan
e Po
ly (d
imet
hyls
ilox
ane)
Dic
hlor
odif
luor
omet
hane
P
oly
(dim
et hy
lsil
oxan
e)
Ben
zene
P
olye
thyl
ene
n-H
exan
e P
olye
thyl
ene
1-B
enze
ne-a
zo- 2
-nap
htho
l N
atur
al r
ub
ber
sw
olle
n w
ith
CC
14
1,l-
Dip
heny
leth
ane
Nat
ural
ru
bb
er
1,l-
Dip
heny
leth
ane
Pol
ybut
adie
ne w
ith various
Hex
aflu
orob
enze
ne
cis- 4
Pol
ybut
adie
ne
Dod
ecan
e cis- 4-
Pol
ybut
adie
ne
Hex
atri
acon
t ane
cis- 4
-Pol
ybut
adie
ne
cis : t
rans
: vin
yl r
atio
s
0.00
2-
0.03
Tra
ce-
0.28
0.15
- 0.
34
0.16
- 0.
25
0.0-
1.0
Tra
ce-
0.47
Tra
ce-
0.49
0.02
- 0.
45
0.05
- 0.
55
0.10
- 0.
60
27-
70
25
25-
45
25-
45
0-
60
25
25
80
80
80
141
142
143
143
144
145
145
146
146
146
2 -I T > r L
x 6
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MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 351
diffusion data. interpreted in terms of Fujita's free volume theory with due consideration of the different SB S domain morphology.
A new method of analyzing unsteady-state sorption data was developed to determine the D and S of vapors in polymer films [107]. The equilibrium weight increase yields the solu- bility directly. and i t s concentration dependence, A complete method for the analysis of either absorption or desorption results w a s pre- sented for a study of the concentration dependence of D. method was applied to Fujita free volume theory. and the experimental procedures are also discussed in detail.
nique was attempted by Chartoff and Chiu [lOS]. Here, the
DMF used had D values in the range 20 x
em / s . For the polyvinyl acetate-chlorobenzene system at
25OC, D w a s of the order of 1.5-2 .0 x cm /s [log]. The sorption mode characteristics of methanol and ethanol in nylon-6 fibers were investigated by the application of the differential sorption method 11101. The sorption vs diffusion behavior was interpreted in terms of clustering theory. Blackadder studied the sorption of carbon disulfide, methanol, and chloroform by poly(ethersu1fone) (PES) [ 1111. The thermal history of this polymer showed a marked effect on the sorption kinetics, which are non-Fickian.
Permeabilities and diffusivities of methyl chloride and ben- zene vapors at low activities in 2 mil thickness FEP Teflon films were measured in a continuous flow permeation cell in the 47-150°C temperature range and at 0.76 torr partial pressure [ 1121. penetrant partial pressures, and the permeation process was described by the Henryf s law sorption-Fickian diffusion model. These data are summarized and compared to other gases 11131 in Tables 1 7 and 18. Thirty-nine organic liquids were studied as to their sorption by nylon using a TGA instrument [114] in the 25 to 200°C temperature interval. E values for these
liquids were observed to be in the 5-13 kcal/mol range. It is seen that ED for only two of the penetrants correlated reasonably
well with the Lennard-Jones collision diameters ( d ) of the penetrant. E computed from the Arrhenius relation exhibited a linear
2 dependence on d . Haga studied Case I1 swelling for the crystalline polyethy-
lene terephthalate (PET)-chloroform system and reported that
The penetrant-diffusion characteristics were
Analysis of the unsteady-state data gives D
The The apparatus
A study of crosslinking i n polyimides by a diffusion tech-
to 1 x 2
2
Ghavamikia and
In all the cases, P and D were independent of the
D
D
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352 AMINABHAVI, AITHAL, AND SHUKLA
TABLE 1 7
Transport and Sorption Parameters for Methyl Chloride and Benzene Vapors in FEP Teflon Films [112]
Parameter Methyl chloride Benzene
1 . 2 6 x 1 . 6 2 x l o w 2 3 Po [cm (STP)/cm*g.cm g]
E (kJ/mol) 34.8 49.5
3.941 307.5 D o (cm / s )
E D (kJ/mol) 50.1 69.1
So [cm (STP)/cm *g*cmHgl
p 2
3.21 5.27 x 3 3
AHs (kJ/mol) - 15.3 - 1 9 . 6
the swelling mechanism changed from Fickian to Case I1 through the intermediate swelling with an increase in the solvent activity [ 1151. The intermediate swelling of PET in solvents in- cluding chloroform, trichloroethylene, and tetrachloroethylene was analyzed on the basis of a combination of the Fickian and Case I1 mechanisms and w a s classified into two categories:
TABLE 18
Selected Properties of Some Vapor Penetrants in FEP Teflon Films [112, 1131
Henry’s law solubility coefficient
at 90°C, 3 s x 1 0 Lennard- Jones
3 diameter E D
Penetrant d (8) (kJ/mol) cm (STP) /cm3*cmHg
Methane 3.76 41.3 2.86
Ethane 4 .44 53.8 5.83
Propane 5.12 59.4 8.50
Methyl chloride 4.18 50.1 5.14
Benzene 5.35 69.1 34.7
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MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 353
(a) the Fickian and Case I1 mechanisms in which they were operative independently and simultaneously and (b) the mech- anism which could not be described in terms of the Fickian and Case I1 modes [116]. Also, the temperature dependence of the intermediate swelling mechanism was reported for the PET fiber- chloroform system. Hopfenberg et al. reported that a remark- able change in transport had not been previously recognized for the polystyrene- hydrocarbon system [ 1171. Thomas and Windle found that for the PMMA-methanol system a Fickian contribu- tion to the swelling kinetics increased with increasing tempera- ture 11181. Aoki and Morita suggested that the sorption mode changes from the sigmoidal (or the two-stage type) to the Case I1 type at a given solvent activity with increasing tempera- ture for the PET film-tetrachloroethylene system [ 1191.
were measured at 40, 50, and 6OoC, with benzene activities ranging from 0.02 to 0.3 [ 1201. found to be Fickian; however, evidence of non-Ficldan transport was found at the highest activity levels. Values of D for ben-
zene ranged from 10 cm /s at 4OoC to cm / s at 6OoC in the limit of low concentrations. Nonlinear isotherms observed for benzene sorption were successfully interpreted in terms of the dual mode model for sorption in glassy polymers, whereby the sorbed penetrant exists as two populations: one according to Henry's law and the other following a Langmuir isotherm. Non-Fickian transport data were correlated with a model which superimposes diffusion of both the Henry's law and Langmuir populations (the "partial immobilization" model) upon first-order relaxation of the polymer matrix.
films in chloroform and n-hexane mixtures as a function of chloroform concentration [ 1211 . With an increase in concentra- tion, the swelling kinetics varied from Fickian to Case I1 be- havior. Case 11 modes was found to satisfy a superposition of the two limiting cases. The magnitude of D obtained for PET was re- markably smaller than that reported for the swollen amorphous polymer. In a study by Hayashi, permeation characteristics of benzene, n- hexane , cyclohexane, and their mixtures were in- vestigated for poly(viny1 alcohol)-poly(viny1 acetate) composite membranes [ 1221. pearance size of the membrane was observed in the feeds. The n-hexane and cyclohexane permeated very fast, while benzene hardly permeated.
in various solvents [ranging in solubility parameter values (6)
The kinetics and equilibria of benzene sorption in PET
The diffusion mechanism was
-14 2 2
Haga also studied the swelling kinetics of crystalline PET
The intermediate swelling between the Fickian and
Neither swelling nor shrinkage in the ap-
The swelling behavior of perfluorinated monomer membranes
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354 AMINABHAVI, AITHAL, AND SHUKLA
from 9.4 to 23.4 ( ~ a l / c m ~ ) l ' ~ ] has been studied, and i t w a s found that the sample pretreatments and the type of the func- tional group have a strong effect on their swelling properties [ 1231. The swelling of the sulfonate membrane is higher than that of the carboxylate membrane; however, membrane swelling can be increased by quenching the sample and increasing the temperature of the solvent.
The hygroelastic behavior of PMMA, in which the diffusion mechanism is characterized by a sharp advancing boundary between the swollen shell and the core, w a s studied 11241. A highly anisotropic swelling response was observed for methanol at 6OOC. The size of the core and its relative dimensions determine the directional swelling strains of the PMMA specimen. The effects of polymer composition and penetrant molecular size on S and D of alcohol vapors in a series of well-characterized isoprene-methyl methacrylate copolymers and their correspond- ing homopolymers were investigated at room temperature [ 1251. Alcohols used in this study were methanol, ethanol, propanol, and butanol. The rate of sorption behavior changed progres- sively from Fickian to non-Fickian to Case I1 to "super Case 11" mode with increasing methyl methacrylate (MMA) content in the polymers. The equilibrium solubility of the alcohols also in- creased linearly with increasing penetrant molecular size for polymers which are above their T
which are below their T The apparent D values decrease
with increasing molecular volume of the penetrants. Also, D decreased exponentially with increasing MMA content i n these polymers.
whitened polypropylenes was studied at 40- 6OoC [ 1261. The rate of penetration of chloroform in whitened samples (prepared by uniaxial stretching) was slower than that of the undeformed material. while in the undeformed region i t was a combination of Fickian and Case 11.
relevant data are given in Table 19.
segregated polybutadiene /polystyrene blends were reported [ 1271. The results exhibited a non-Fickian mode. by Chiou and Paul i t was found that in the equilibrium sorp- tion of ethanol, the kinetics varied in a complex manner (for the blends of polyvinylidene fluoride and PMMA) with composi- tion, ranging from Case I1 kinetics for glassy blends to Fickian diffusion for rubbery ones, and is a strong function of prior history [ 1281.
and decreases for polymers 9
9'
The transport of chloroform in undeformed and stress-
The process was Fickian in the whitened region,
The The ED value was about 1 0 . 6 kcal/mol.
Experimental data on hexane vapor sorption in phase
In a study
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MOLECULAR T R A N S P O R T OF ORGANIC LIQUIDS 355
TABLE 1 9
Diffusion Data for Chloroform in Undeformed
Polypropylene [ 1261
D x l o 8 2
( O C ) (cm /s) Temperature
40.0
44.9
48.0
55.3
59.7
1 . 2 1
2.29
2. 81
18. 8
26.0
Research developments in the field of thermomechanical analysis (TMA) have led to the availability of commercial appara- tus capable of precise measurements. used to study the rates of polymer swelling and diffusion phenomenon [129] for a number of organic liquids. These data are summarized in Table 20.
Thomas and Windle [130], while studying the diffusion mechanisms of the PMMA-methanol system, suggested that Case I1
A D u Pont 941 TMA was
TABLE 20
Diffusion and Sorption Data of Organic Solvents [129]
8 D x 1 0 2 Polymer Liquid (cm /s)
Poly-n-butyl methacrylate Ethanol 17.0
Polymethyl acrylate Methanol
Ethanol
6. 8
6 .0
Polystyrene Toluene 150.0
Methyl ethyl ketone 81.0
Amy1 acetate 43.0
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356 AMINABHAVI, AITHAL, AND SHUKLA
diffusion of penetrants in polymer films is associated with con- strained swelling of the film and the generation of internal stresses. nitrocellulose/nitroglycerine films was studied [ 1311 . In all cases, although fractional uptakes were approximately propor- tional to the square root of time, they were also independent of film thickness. Such a behavior indicated a Case 111 mech- anism in which the film expands uniformly with no appreciable concentration gradients. A kinetic equation which describes uptakes up to 90% was suggested.
Diffusivities of the large inflexible DDT molecule [ 1 , 1 - bis( 4-chloropheny1)- 2,2,2-trichloroethane] and of the long, flexible n- hexadecane have been obtained in various polybuta-
dienes using I4C-labeled molecules and the thin smear surface activity method at temperatures of 25, 35, and 45OC [132]. In all cases, D decreased slowly as the trans content of the poly- mer increased from zero to 75%. This was attributed to a de- crease of free volume with decreasing cis content. A more rapid fall in D at higher trans contents of the polymer occurs due to the presence of crystallites, and this fall is greater for DDT than for n-hexadecane.
cation exchange membranes in various organic solvents were investigated 11331. brane was strongly related to the type of ion-exchange group and was not influenced by the perfluorinated nature of the polymer. swelling peaks. groups and the organic material of the membrane. other hand, there was no distinct swelling for membranes with carboxylic acid groups.
The sorption of isopropyl nitrate and acetone into
The swelling behaviors of Nafion and six radiation-grafted
It was found that the swelling of the mem-
Membranes with sulfonic acid groups exhibited two These peaks were attributed to the ionic
On the
1 1 1 . CONCLUSIONS
The available data on permeability, diffusivity , and solu- bility of organic liquids through polymer membranes have been summarized. small organic molecules through polymer membranes has many goals. However, one of the ultimate a i m s of research in this field has been to establish mechanisms and laws relating solu- bility and transport in polymer membranes to their molecular properties, the nature of the penetrants, and the film morphology.
The considerable interest that exists in permeation and diffusion characteristics of polymers arises largely from the
The accelerating research in the transport of
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MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 357
fact that a number of important practical applications depend wholly or in part on such phenomena. These applications in- clude protective clothing, packaging materials for foods and beverages, selective barriers for the separation of gas and liquid mixtures, biomedical devices, and liners in hazardous waste-containment facilities. through polymer films will continue to be an active area of research for years to come.
polymer membranes has taken place in our laboratories during the past several years [ 1471. the extent of polymer diffusion by a variety of organic solvent molecules. in relation to their mechanical properties have been of interest. Major fundamental questions regarding the type of diffusion mechanisms within the films have been addressed by employing phenomenological models. will be covered in a forthcoming short review [148].
The transport of small molecules
Additional work in the area of solvent transport through
Our efforts have focused on
Solvent transport properties of polyurethane films
An overview of these investigations
ACKNOW LEDCMENTS
S. S. Shukla wishes to thank the Robert A . Welch Founda- tion, Houston, Texas, for partial support toward the prepara- tion of this manuscript. U . S. Aithal thanks the University Grants Commission, New Delhi, India, for the award of a teacher fellowship to study for his PhD in Karnatak University. T. M. Aminabhavi thanks the administrators of Karnatak Univer- sity, Dharwad, India, for a permission during the summer of 1988.
REFERENCES
[ l ] P. E. Cassidy, T . M. Aminabhavi, and C. M. Thompson,
[2] H. B . Hopfenberg (ed.) , Permeability of Plastic Films and Rubber Chem. Technol., 56, 594 (1983).
Coatings to Gases, Vapors and Liquids. Plenum, New York, 1974.
Academic, New York, 1968.
Press, London, 1975.
State Mater. Sc i . , 1 1 ( 2 ) , 123 (1983).
[3] J. Crank and G . S. Park (eds.) , Diffusion in Polymers,
[ 41 J. Crank, Mathematics of Diffusion, Oxford University
[5] H . L. Frisch and S. A . Stern, CRC C r i t . Rev. Solid
Dow
nloa
ded
by [
Nor
th C
arol
ina
Stat
e U
nive
rsity
] at
03:
17 1
0 D
ecem
ber
2014
358 AMINABHAVI, AITHAL, AND SHUKLA
V. T. Stannett, H. B . Hopfenberg, and J. H. Petro- poulos , in M . T . P . International Review of Science, V o l . 8, Macromol. Sci. (C. E . H. Bawn, ed.) , Butter- worths, London, 1972, p. 239. R . M. Barrer, Diffusion In and Through Solids, 2nd ed., Cambridge University Press, Cambridge, 1951. J. S. Vrentas and J. L. Duda, AIChE J.. 25, 1 (1979). P. H . Abelson, Science, 233(4763), 509 (1986). S. Sourirajan, Reverse Osmosis and Synthetic Membrane, Publication Ottawa, Canada, Kia ORL, 1977. R. C. Binning, R . J. Lee, J. F . Jennings, and E. C . Martin, Ind. Eng. Chem. , 53, 45 (1961). M . Yoshikawa, H. Yokoe, K . Sanui, N . Ogata, and T. Shimidzu, Polym. J., 16, 653 (1984). R . N . Howard, J. Macromol. Sci.-Rev. Macromol. Chem. , C 4 ( 2 ) , 191 (1970). G . J . Van Amerongen, Rubber Chem. Technol . , 37, 1065 (1964). J. P. Gupta and M. V. Sefton, J. Appl . Polym. S c i . , 31, 1721 (1986); 32, 4313 (1986). J . P. Gupta and M. V . Sefton, I b i d . , 31, 2109 (1986). H. Roedicker and N . Radke, Plaste Kautsch. , 23, 356 (1976). E . N . Rosolovskya and J . Salwinsld, Vysokomol. Soedin . , Ser . A , 18 , 1428 (1976). G . A . Corbin, R . E . Cohen, and R . F. Baddour, J. Appl . Polym. S c i . , 30, 1407 (1985). J . Pinsky, A . Adakonis, and A , R . Nielsen, Mod. Packag. , 33( 61, 130 ( 1 966). J . L. Scotland, U . S . Patent 3,647,613 (1972). L. J. Haynes and D. D. Dixon, J . A p p l . Polym. S c i . , 23, 1907 (1979). J . Koszinowski, I b i d . , 32, 4765 (1986). K . Becker, J. Koszinowski, and 0. Piringer, Dtsch. Lebensm.-Rundsch., 8, 257 (1983). M. Johnson and J. F . Westlake, J. Appl . Polym. S c i . , 19, 1745 (1975); 19, 375 (1975). J. P. Gupta and M . V. Sefton, I b i d . , 31, 2195 (1986). S . Sternberg and C . E. Rogers, I b i d . , 12, 1017 (1968). B . W . Hilton and S . Y . Nee, Ind. Eng. Chem. , Prod. Res . D e v . , 17, 80 (1978). H . C. Ng, W . P. Leung, and C . L. Choy, J. Polym. S c i . , Polym. Phys . E d . , 23, 973 (1985). A . Peterlin, J . Macromol. S c i . - P h y s . , B11, 57 (1975); J. L. Williams and A . Peterlin, J. Polym. S c i . , Part A-2, 9, 1483 (1971).
Dow
nloa
ded
by [
Nor
th C
arol
ina
Stat
e U
nive
rsity
] at
03:
17 1
0 D
ecem
ber
2014
MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 359
311
321
C 331
[ 341
C 351
1361 C 371
381
[ 391 401
1421
[ 431
t 451
[ 461
[ 471
481
[ 491
[ 501 [ 511
[ 541
L. Araimo, F . DeCandia. R. Russo, V. Vittoria, and A . Peterlin, J. Polym. S c i . , Polym. Phys . E d . , 1 6 , 2087 (1978). F. DeCandia, R . Russo, V. Vittoria, and A . Peterlin, I b i d . , 20, 269 (1982). F. DeCandia, A. Perullo, V . Vittoria, and A. Peterlin, J. A p p l . Polym. Sci. , 28, 1815 (1983). 0. T. Aboul-Nasr and R. Y . M. Huang, I b i d . . 23, 1851 (1979). 0. T. Aboul-Nasr and R . Y . M. Huang, I b i d . , 23, 1833 (1979). J. Koszinowski, I b i d . , 31, 2711 (1986). R . Y . M . Huang and V. J. C. Lin, I b i d . , 12, 2615 (1968). S . Hayashi, T. H i r a i , F. Hayashi, and N . Hojo, I b i d . , 28, 3041 (1983). A . A . El'bert, Zh. Fiz. Khim. , 50 , 1804 (1976). H. Roedicker and N . Radke, Chem. Technol . , 28, 271 (1 976). S. K . Ghosh and B. S. Rawat, Indian J. Technol . , 5 , 101 (1967). R . Laine and J. 0. Osburn, J. A p p l . Polym. S c i . , 15 , 327 (1971). R. W . Coughlin and F. A . Pollak, AIChE J . , 15, 208 ( 1 969). C. J. Durning, J. L. Spencer, and M . Taber, J . Polym. S c i . , Polyrn. Le t t . Ed. , 23, 171 (1985). L. N . Britton, B. Ashman, T. M. Aminabhavi, and P. E. Cassidy, J. A p p l . Polym. S c i . , (1989) In Press. L. N . Britton, B . Ashman, T . M. Aminabhavi, and P. E. Cassidy, J. Chem. Educ. , 65(4), 368 (1988). R . W. Weeks Jr. and M. J. McLeod, Am. Ind . Hyg. Assoc. 3 . , 43, 201 (1982). A . S. Michaels, W. R. Vieth, A . S. Hoffman, and H. A . Alcalay, J. A p p l . Polym. S c i . , 13, 577 (1969). T. N . Wang, Am. Chem. S O C . , Div . O r g . Coat. Plast. Chem. P a p . , 35 , 442 (1975). M. J. Smith and N . A. Peppas, Polymer, 26, 569 (1985). N . A . Peppas and K . G. Urdahl, Eur. Polym. J., 24, 1 3 (1988). K . U . Urdahl and N . A. Peppas, Polym. Eng. S c i . . 2 8 , 96 (1988). N . A . Peppas and K . G . Urdahl, Polym. Bul l . , 16, 201 (1 986). J. B . Roucis and J. G . Ekerdt, J . A p p l . Polym. Sci., 27, 3841 (1982).
Dow
nloa
ded
by [
Nor
th C
arol
ina
Stat
e U
nive
rsity
] at
03:
17 1
0 D
ecem
ber
2014
360 AMINABHAVI, AITHAL, AND SHUKLA
L. A . Errede, I b i d . , 31, 1749 (1986). M. C . Gupta, V . P. Bansod, and I . D. Patil, Polym. Commun., 28, 204 (1987). C . L. Choy, W . P. Leung, and T. L. Ma, J. Polym. Sci., Polym. Phys . Ed., 2 2 , 707 (1984). N . A . Peppas and J . L. Sinclair, Colloid Polym. Sci., 261, 404 (1983). K . G . Urdahl and N . A . Peppas, J . A p p l . Polym. Sci., 33, 2669 (1987). L . M . Lucht and N . A . Peppas, Ibid., 33, 1557 (1987). N . A . Peppas and L. M. Lucht, Chem. Eng. Commun., 30, 291 (1984). L . M . Lucht and N . A . Peppas, Fuel Chem. Prepr. , 29(1), 213 (1984). B . D . Barr-Howell, N . A . Peppas, and T . A . Squires, J. A p p l . Polym. Sci., 3 1 , 39 (1986). J . P . Harmon, S. Lee, and J. C . M . Li, J . Polym. Sci., Polym. Chem. E d . , 25 , 3215 (1987). R . W . Connelly, N . R . McCoy, W. J. Koros, H . B . Hop- fenberg, and M. E . Stewart, J. Appl . Polym. Sci., 34, 703 (1987). G:C. Sarti, C. Gostoli, and S. Masoni, J. Membr. S c i . , 1 5 , 181 (1983). D. J . Enscore, H. B . Hopfenberg, and V . T. Stannett, Polymer, 18, 793 (1977). D. J . Enscore, H . B . Hopfenberg, and V. T. Stannett, Polym. Eng. Sci., 20, 102 (1980). L. Nicolais, E. Drioli, H. B . Hopfenberg, and A . Apicella, Polymer, 20, 459 (1979). E. Drioli, L. Nicolais, F. Perone, and M. Napkis, J. Membr. Sci., 5, 349 (1979). R. H. Holley, H . B . Hopfenberg, and V . T. Stannett, Polym. Eng. Sci., 1 0 , 376 (1970). R . A . Ware and C. Cohen, J. Appl . Polym. S c i . , 2 5 , 717 (1980). R . P. Kambour, C. L. Gruner, and E . E. Romagosa, J. Polym. Sci., Polym. Phys . Ed., 11, 1879 (1973). R. P. Kambour, J . Polym. Sci., Macromol. R e v . , 7, 1 (1973). I . Narisawa, J . Polym. Sci., Polym. Phys. E d . , 1 0 , 1789 (1972). J. A . Barrie and D. Machin, Trans . Faraday S O C . , 67(577, Part l ) , 244 (1971). E. Southern and A , G. Thomas, Trans . Faraday Soc.. 63, 1913 (1967). E. Southern, Use of Rubber in Engineering, Maclaren, London, 1967, p. 49.
Dow
nloa
ded
by [
Nor
th C
arol
ina
Stat
e U
nive
rsity
] at
03:
17 1
0 D
ecem
ber
2014
MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 36 1
801
[ 811
821
[ 831
[ 841 851
[ 861
871
[ 881
[ 891
901
1911
[ 921
[ 931
[ 941
[ 951 [ 961
971
[ 981 1991
[ 1001 [ 1011
C. M . Blow, K . Exley, and D. W . Southwart, J. I R I , 2 , 282 (1968). W . R. Brown, R. B . Jenkins, and G. S. Park, J . Polym. S c i . , Polym. S y m p . , 41, 45 (1973). S . N . Lawandy and F. H . Helaly, J . A p p l . Po lym. S c i . , 32, 5279 (1986). E. Southern and A . G . Thomas, J . Polym. S c i . , Par t A , 3 , 46 (1965). A . Aitken and R . M. Barrer, Trans. Faraday SOC., 51, 116 (1955). S. Takahashi, J. A p p l . Polym. S c i . , 28, 2847 (1983). I. A . Abu-Isa, SAE Technical P a p e r S e r i e s , No. 800786, Passenger Car Meeting, Dearborn, Michigan, June 9-13, 1980. I . A . Abu-Isa, R u b b e r Chem. T e c h n o l . , 56, 135 (1983); 56, 169 (1983). M. E. Myers and I. A . Abu-Isa, J . A p p l . Po lym. S c i . , 32, 3515 (1986). J. A . Barrie, D. Machin, and A . Nunn, P o l y m e r , 1 6 , 811 (1975). J. M. Bouvier and M. Gelus, R u b b e r Chem. T e c h n o l . , 59, 233 (1986). D. R. Paul and 0. M. Ebra-Lima, J . A p p l . Polym. S c i . , 1 9 , 2759 (1975). E. V. Meerwall and R . D . Ferguson, I b i d . , 23 , 3657 (1979). R. W. Weeks Jr. and B. J. Dean, A m . I n d . Hyg. A s s o c . J . , 38, 721 (1977). E. B. Sansone and Y . B . Tewari, I b i d . , 39, 921 (1978); 39, 169 (1978); 41, 170 (1980). E. B. Sansone and Y. B . Tewari, in Environmental A s p e c t s of N-Nitroso Compounds (E. A . Walker, M . Caste- naro, L. Griciute, and R. E . Lyle, eds.) , International Agency for Research on Cancer, Lyon, 1978, pp. 517-529. S. Takahashi, J. A p p l . Polym. S c i . , 28, 2847 (1983). M. A. Grayson, P. S. Pao, and C. J. Wolf, J . A p p l . Polym. S c i . , Part B , Polym. P h y s . , 25, 935 (1987). W . Nierzwicki and 2. Majewska, J. A p p l . Polym. Sc i . I
24, 1089 (1979). M. V. Sefton and J . L . Mann, I b i d . , 25, 829 (1980). N. S. Schneider, J. L. Illinger, and M. A. Cleaves, Polym. E n g . S c i . , 26, 1547 (1986). G . W. C . Hung, Microchem. J. , 19, 130 (1974). G . W. C . Hung and J. Autian, J . Pharm. S c i . , 6 1 ( 7 ) , 1094 (1972).
Dow
nloa
ded
by [
Nor
th C
arol
ina
Stat
e U
nive
rsity
] at
03:
17 1
0 D
ecem
ber
2014
36 2 AMINABHAVI, AITHAL, AND SHUKLA
I 1021
[ 1031
[ 1051
t 1181 [ 1191
I1201
1211 [ 1221
[ 1281 1291
H. B . Hopfenberg, N . S. Schneider, and F. Votta, J. Macromol. Sci. -Phys . , B3(4), 751 (1969). E . Holger and R . Helmut, Makromol. Chem. Rapid Commun., 6 , 187 (1985). I. A . Korshunov, N . F. Novotorov, and A . Lukuttsov, T r . Khim. Khim. Tekhnol . , 3 , 219 (1965). S. S. Kulkarni and S. A . Stern, J . Polym. S c i . , Polym. Phys . ' E d . , 21, 441 (1983). T. Masuko, N. Choji, M . Karasawa, and K . Ishi , J . A p p l . Polym. S c i . , 22, 1105 (1978). 0 . T. Aboul-Nasr and R. Y . M . Huang, I b i d . , 23, 1819 (1979). R. P. Chartoff and T . W. Chiu, Polym. Eng. Sc i . , 20, 244 (1980). C. M . Hansen, I b i d . , 20, 252 (1980). A . Sfirakis and C . E . Rogers, I b i d . , 20, 294 (1980). H. Ghavemikia and D. A . Blackadder, Polymer, 21, 901 (1 980). T. Duncan, W. J. Koros, and R. M. Felder, J. A p p l . Polym. S c i . , 28, 209 (1983). N. Yi-Yan, R. M . Felder, and W . J . Koros, I b i d . . 25, 1755 (1980). A . M. Beyerlein, B . S. Sheth, and J. Autian, J . Pharm. S c i . , 60(9), 1317 (1971). T. Haga, J. Polym. Sc i . , Polym. Let t . E d . , 20, 629 (1982). T. Haga, Seni Gakkaishi, 32, T-210 (1976). H. B . Hopfenberg, R . H. Holley, and V. Stannett, Polym. S c i . , 9 , 242 (1969). N. Thomas and A . H Windle, Polymer, 1 9 , 255 (1978). T. Aoki and Z. Morita, The 24th Discussion Meeting of Dyeing Chemistry, Japan, Prepr in t , 1979, p. 53. C. J. Patton, R . M . Felder, and W. J. Koros, J. A p p l . Polym. S c i . , 29, 1096 (1984). T. Haga, I b i d . , 26, 2649 (1981). S . Hayashi, T. Hirai, F. Hayashi, and N . Hojo, I b i d . , 28, 3041 (1983). R. S. Yeo and C. H . Cheng, I b i d . , 32, 5733 (1986). D. Cohn and G. Marom, Polym. Eng. S c i . , 22, 870 (1982). A . Sfirakis and C. E . Rogers, I b i d . , 21, 542 (1981). C. C . Chau and D. L. Fear, I b i d . , 26, 1533 (1986). Y. S. Kang, J . H . Meldon, and N . H. Sung, I b i d . , 26, 1045 (1986). J . S. Chiou and D. R . Paul, I b i d . , 26, 1218 (1986). D. Machin and C. E . Rogers, I b i d . , 10, 300 (1970).
Dow
nloa
ded
by [
Nor
th C
arol
ina
Stat
e U
nive
rsity
] at
03:
17 1
0 D
ecem
ber
2014
MOLECULAR TRANSPORT OF ORGANIC LIQUIDS 363
N . L. Thomas and A. H . Windle, Polymer, 22, 627 (1 981). J. D. CosgrOve, T . G. Hurdley, and T. J. Lewis , Ib id . , 23, 144 (1982). R. B. Jenkins and G . S. Park, J. Membr. Sc i . , 15, 127 (1983). R. S. Yeo, S. F. Chan, and J. Lee, Ib id . , 9, 273 (1981). H. Fujita and A . Kishimoto, J. Polym. Sc i . , 28, 547 (1 958). H. Fujita, Fortschr. Hochpolym. Forsch . , 3 , 1 (1961). A . Kishimoto, J. Polym. Sc i . , Part A , 2 , 1421 (1964). H. Fujita, A . Kishimoto, and K . Matsumoto, Trans . Faraday Soc., 56, 424 (1960). A. Kishimoto and Y . Enda, J. Polym. Sc i . , Part A . 1 , 1799 (1963). A . C. Newns, Trans . Faraday Soc. , 59, 2150 (1963). M. S. Suwandi and S. A . Stern, J. Polym. S c i . , Polym. Phys . Ed . , 1 1 , 663 (1973). M. S. Suwandi, PhD Thesis, Department of Chemical Engineering and Materials Science, Syracuse University, 197 3. R . A. Assink, J. Polym. Sc i . , Polym. Phys . Ed . , 15, 227 (1977). M. Fels and R. Huang, J. Appl. Polym. Sc i . , 14, 537 (1970). R. E. PattIe and P. J. A. Smith, Trans. Faraday SOC. , 62, 1776 (1966). C. P. Wong, J. L. Schrag, and J . D. Ferry, J. Polym. Sc i . , Part A-2. 8 , 991 (1970). R. D. Ferguson and E. Von Meerwall, J. Polym. Sc i . , Polym. Phys . Ed . , 1 8 , 1285 (1980). U. S. Aithal, PhD Thesis, Karnatak University, Dharwad, India, (1989- 90). U. S. Aithal, T . M. Aminabhavi, R. H. Balundgi, and S. S. Shukla, J. Macromol. Sci.-Rev. Macmmol. Chem. Phys . , (1990) In press.
Dow
nloa
ded
by [
Nor
th C
arol
ina
Stat
e U
nive
rsity
] at
03:
17 1
0 D
ecem
ber
2014
