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MECHANICAL PROPERTIES OF HIGHLY FILLED ELASTOIARS VI.
Influence of filler content and temporature on* ultimate tensile properties.
'if
Reported by
C.J. Nederveen and H.R . Bre
U
S
S
CENTRAAL* LABORATORIUM
, .N.o. D D C"RECEIVED U'. AUG 7 1967
AU AUG8 1967 B
CFSTI
•Lk
mcmN
WCHANICAL PROPERTIES OF HIGHLY FILLED ELAWOMERS VI,
Influence of filler content and temperature onultimate tensile properties,
Reported by ..
C.J. Nederveen and H4. Bree
132 JULIANALAAN - DELFT - TELEPHONE 01730-37000 - THE NET',ERLANOS
CENTRAL LABORATORY TNO
ONR Technical Report No. 6
Mechanical Properties of H=v Fitled Elastomers VI.
Influence of filler content and temperature on
ultimate tensile properties
by
C.J. Nederveen and H.W. Bree
Contribution from the Centrai Laboratory TNO
Delft, Netherlands.
Report No. CL 67/34
Ccntract No. 1 62558-4375
Distribution of this document
is unlimited
Delft, May 1967
CENTRAAL LiBORATCRIWU TNO - DELFT, Holland, Report No. CL 67/34 page 2
MLCHANICAL PROP-RTIa.- OF HIGHLY FILM EiSJTORS VI.
Influence of filler content and temperatu-e on ultimate tensile properties.
Reported by
C.J. Nederveen and H.U. Bree
The work reported here was carried out by:
H.W. Bree, assisted by Preparation and characterization of filled
IMiss I'LP. van Puykeren. polyurethanes.
C.J. Nederveen, assisted by Neasliremeut of tonsiJe properties of filled
J. Wesselius. rubbers.
C.A. Schirippert and Digital read-out and processing of measuring
C.dI. v.d. %'al. data.
R. Nauta, assisted by Eachining of specimens.
G.J. Kap.
B. de Goede (Central Technical Classification of filler substance.
Institute TNO).
CENTRAAL IdLBORATRCIUTI TNO - DELFl, Holl-and, Report Noý CL 67/3A page 3.
SD]MHARY.
1 I. INTRODUCTION.
2. WhiAt UL S-.li3. EUTPFUMANFTAL T' X-MITj
4. DISCUSSION OF RiES•j.ifS.
4.1. Stress-strain data.
1.. 4.2. Modulus of elasticity.
4.3. Failure envelope.
I 4.4. Dewetting.
4,5. Comparison vwith results of tensile creep measurements.
5. CONCLUSIONS.
6. REFERICES.
1. TABLD].CAPTIONS TO FIGUIRES.
FIGURES.
DISTR7TBUTION LIST
V
CENTRAAL LAB•AtTORI24 TNO - D1)FI, Hoiland. Report No. CL 67/34 page 4,
Results are presented of stress-strain tests rerformed at various temperatures
and strain rates on materials filled with various amounts of sodium chloride
-.- * particles with a mean size of 0.1 mam. Stress and straih at rupture decreased with
increasing filler content. For each material investigated it was possible to
construct the well-known failure envelope by means of which the results could be
described adequately.
The dewetting of the particles in the rubbery matrix, sometimes resulting in
a maximum in the stress-strain curve, is ascribed to failure of the rubber between
the particles and not to failure of the rubber-salt bond, because the dewetting
maximum was dependent on temperature and time in the same way as the rupture
properties of the unfilled material.
The results are compared with earlier investigations, e.g. high speed tensile
tests and creep experiments, and a good agreoment is found.
A
4
M-NTRAAL IABORAMRIUM TO - DELT#, Holland, Report No. CL 67/34 page 5.
"In the design of solid rocket motors, a thorough knowledge of the mechanical
Sb h behaviour of solid propellant grains is very important. We especially mention the
formation of cracks in the propellrnt, which laads to malfunction of the motor.
Cracks may be formed during storago; they are then due to shrinkage or theimal
stresses. Or during combustion, when they are due to combustion pressure or
acceleration forces*
The composite ýropellnnt under study consiets of a polyurethane rubber filied
with amaor.Ium perchlorate particles. PFr ease of handling# we have so far used
model substances consisting of the same rubber but filled with an inert mn.terialp
viz. sodium chloride. Vrious fractions of NaC1 were used. The influence of filler
size, shape, concentration and surface treatment on the mechanical behaviour ofthose materiais was studied rnd reported earlier (1 - 8).
The present report describes fnilure properties of the model ,xiterials filled
with s•at particles of one particulnr size (about 0.1 mn): tensile tests were
performed on dumb-bell-shaped specincns at various tUmperutures.
4
CMTRAAL I s•RAADEIUM TN - DIELT, Hollnd, Report No. CL 67/34 poge 6.
2. M
All smplos of filled and iifilled polyurethare rubbers investigated were
based on r. linetr (polyprop)lefe othor)glyool (Demophn 3600, Forben ?abriken
"Bayer, leverkusen, Germany) with a molecular weight of about 2000. The moleculee
"of this polyether were lengthened with toluene diisocyenae and croselinked by
means of trimethylol propane in the presence of z catalyst. Full details conce.
ing the preparation of these filled and unfilled rubbers wore given previaely(0 t2,7).
A series of samples waz prepared containing various nmounts (0, 15, 30 an
4% by volume) of sodium chloride particles of about 100 tAm [fraction no* 4 (2),
labelled 90-105 jm, qwith largest dimensions between 50 amd 175 jAm am uirleat
dimensions between 25 rnd 100 .ml. No surfactant was used in the preparation of
these materials. In order to provide sufficient material for this study, all jcompositions were made in sixfold,
Det,-ils of e.'ch batch are given in Table 1 *. This table contains, for each
batch, the chemical composition of the prepolymor; the content of filler, as
calculated from the weights of the ingredients used, and as calculated from the
density; the fraction number and the size of the filler; the equilibrium wvelling
ratio (W" vol. increas.) in two different solvents (chlorofor- and trichloroethyl-
oev) ; the density, d. Details of those routine control mezurements were given
exlio( 2 ) Tho last column of Tnblc I gives the temperatures at which stress-
strain toots were performod.
From Table I it is seen thýt the chomical composition of the rubbery binder
was approximately thx same for all s-mploo prepared (columns 2, 3, 4). Columns 5
A 6 show thnt the difforences botwoon the volmo oon- atration as calculated
from th- weights of the ingromionts used and that calcul.tted from the density are
inaller th.-n 1% 0 vol.'.
As there exists n distitet rel-tionship hatween croselinkLing density and
equilibrium •ellik, a constancy of welling data (column 10 & 11) indicatte
a eooati-acy of the crjso-lini..ng deouty.
The a'%torials woro stored at 20oC and 65ý relative huidity for at least 14
dry prior to the mnc,.inig of test specimenso
4 .) . page 20.
I +
CWYPRAL LABCRAk-'CLIU TNO - DELtT, Hollanu; Report No. CL 67/34 page 7
3. E PoM-IMF TM1 1M-
Dumb-bell-31aped spccimenc were machined: on a modified Maximat Standard ,
r from th,4 materials de.-Oribed abo.,it Shapc and dimensions arV given in Fig. 1
r Stress-strain measiurnents -.:,re performcd on n tensile testing machine at
*+ vario-3 cross-head snceds (1O, 20, 40 and 60 cm/min), P.. at various temperatures(-45t -40, -735t -30: -20, 0 and "•C).
j|+ A small tensile test'r, developed by the Rubbew Research Institute TNO, was
kinraly plnced at our disposal b6 the sad institute. A cabinet was placed &round
the specimens, including the grips, and thermostated fas was blown :,ito the c:.'mber.
For temperatures above arbicnt, .lectiically heated air .;3s ured. For temperatures
below ambient, air was blown alonr solid C 2 . In the cabinet, a temperature 3cisor
operated an electrinaes ieatirn deovi o nl t'nus regrulated the temperature. The
sensor element ~ calibrated -zitli , tneiv.cucter placed in the cabinet.
The tensilo force w.- measured .-.th ,i force transducer :t tha upper clamp
T' (the lower cizmp vzý.s the drivlen clamp). The elUctrical output of this transducer
was fed to a str.p cha ,et trccrder. The voltage of tine signal was printed digitally
at fixed Aime inteý'vals o:' ? ccc. These data wer'e used for evvluaticn of the
results, usinr a digital computer, !2t3r.r:ards.
The tensile stress, c, was c lcu!atea with respect to the oripinal cros-qsec-
'tion of the prism-tic part of the opecim¶.n.
* The tensile a+rain, t: of tle .•ri-rmatic nmrt of the specimere depends cn thE
displacement, .%1, of the c'Aar- . Ao the cr(,s-section is not .jiifovr 1,nd tho
material behaves :Ln-dook' z, tn exact v'aluu o-' e cannot be+ obtained from the
clamp di. 1,lacemon:t. C:i•.P+a;... i+ found by as=W.mir the material to be
Hookenn mvirr'hn, an,4 ft r'nkXiM'-' C by :as'uaz thAt the heada of the n;eci-
meol do not det'I.AU ut ')1l:
In this x.tsi~ ' 1i k!)v 'In..ten th~e lot),,U. W~t-ean the rv-t b1 den 0
the ,trllcrt -.A V.L'-_ 'th of .'ýhc; pcmon. ior 11,h Uw..on Valua
+' It
cf 1' 'u in f ; i or Vi-. prim+tic 3Lt
of the .ipccimttr.
I 1Maier &Co. Ha.UAll "
CEIltRaAL LABORATORIUM TNO - DMEE, Holland, Report No. CL 67/34 page 8.
!
Shorrtly after the start of the experiment, deformations are small, and c will
. be close to cmin; near the end of the test the hods show little or no dewettimg,
so c will be closer to cmax" For convenience, tne mean value of cmax and cmin was
chosen as representative for e. From the dimensions of the dumb-bell according to
Fig. 1 it followa that
c= 1.48 (l/1 ) (2)
However, the real strain msy differ up to e5Op from this value.
Using this result, it was fouid that tie four cross-4head peeds mentioned-1
earlier correspond to strain rntes of respectively 0.025, 0.05, 0.1 and 0.15 s .
These figures are much smaller than the strain rates at which similar materials,
prepared in our labcratory, were tested at Columbia Univer'sity, New York (9):
-10.37, 2.77, 7.40 and 2-.1 s- . The results of "Columbia" Aill be compared trith our
results in the present report. -
ii
CENTRMAL LA. IH TUNO - DEIFT, Holland, Report No, CL 67/34 pag 9.
r ~4. DIS3CUSION OF MMSUS.
4.1. Stress-strain data.
A considerable spread L+ 30o-) was nbserved between the rupture properties of
I. individual specimens from the same batch. An investigation concerning the ultimate
stress at +300C of a number of specimens from various batches revealed that the
j1 mean *slues of about 5 measurements on specimens from one batch were rather close
to those of tests of other batches. From this finding it was concluded that the
batches are prectically identical uith respect to their ultimate piroperties.
Sometimes rupture was observed at one of the ends of the prismatic part of
the specimen, indicating that machining of specimens, or the shape of the specimen,
needed improvement. Results obtained irith these specimens were not rejected,
however, because no deviations from the geaeral behaviour were observed.
Representative results of stress-strain measurements at -various temperatures
are shown Ln Figs 2, 3, 4 & 5; eacii diagram relates to one particular filler
content. The curves presented in these pictures give rerresentatively selected
mean values from about 5 tests. Fig. 2 shoi:s results for the unfilled material.
I.Tith decreasing temperature, the strain-at-break, , reaches a maximum, whereas
the stress-at-break, ah, increases continuously. The maximum observed in the
stress-strain-curve at -45°C h0a. not yet been ex'plained.
Figs 3, 4 and 5 shoew results for tne filled rubbers. Eb and a depend in the
same way on temperature as do the rupture _-oI;er+ies of the unfilled material. A
definite maximum in the stress occurs at low temperatures for all filled materials.
For the 45, filled material, this also shows up at room temperature. This maximum
can be attributed to a tearing of the rubber bridges between particles, the so-
called dewettirn. Because, in these regions, the rubber is strained comparatively
more than the specimen as a whole, the da::ettiln takes place 9t a comparatively
low over-all deformation. This dewetting ',henomenon wll be discussed in more
detail in Section 4.4.
Each of Figures 6 to 12 rivos the stress-strain diagrams -t one constai-t
temperature for various amounts of filler. Observe that stress as well as deforma-
tion at rupture appear to decrease irith increasing filler content.
I
-T
CERAAL LABORATORIUh TNO - DELFT, Holland, Report No. CL 67/34 page 10,
* 4.2. Modulus of elasticity.
The modulus of elasticity, Young's ,Lodulus E, was calculated from the initial
slope of the stress-strain curve.
The tae-ile tester used in our experiments was not entirely suitable for this
type of tests: one of the troubles was that perfectly straight clamping was impossi-
ble. It was es 4 imated that, because of this inconvenience, the initial slope could
be in error up to a factor of two. Despite this the modulus was calculated from
the initial slope. This was done according to the formula:
E a(1+c)/e (3)
In Fig. 13, Young's modulus E is plotted foe the four different filler concentra-
tions as P function of temperature (open symbols). The filled symbols are results
obtained by tensile creep measurements on the same materials (8). Also inserted
are results (crosses) of tensile tests at high strain rates carried out at
Columbia University on similar materials [(9), Figs 1 and 91. MIoduli calculated
from these results in general appear to be 50 to I 0• higher than our results. In
vietr of all the possible errors, and the fact of the differences in the testing
speed, this range of agreement is satisfactory.
4.3, Failure envelope.
It is knoim from the literature (10-15) on ruptu-e properties of filled and
unfilled rubbers that a relationship exists between Eb' Wb' time to break, tb?
and absolute temperature, T. This relationship is described by a curve in a three-
dimensional space. Along the three orthagonal axes are plotted respectively
(273 %b/T), eb and the reduced time-to-break, tb/a Quantity a, is the well-
knov•n time-temperature shift according to the `.L.F.-equation:
log aT = -c 1(T-To)A(c2 +T-To) (4)
The values for aT were obtained from torsional pendulum and torsional creep
measurements at small deformations. The shift factors for the various temperatures
were p&atly published ( 6), and partly oltained from measurements not yet reported.
CENTRAAL LABOUATCIUM TNO - DELFT, Holland, Report No. CL 67/34 page 11.
Unfilled rubber and materials filled with various amounts of sodium chloride were
N investigated, as is indicated in Fig. 14 by different symbols. A curve according
to Eq.(4) was drawn through the individual points. By trial and error it wasIfound that the best fit was obtained through use of the following constants:
T 0 = -350C, c1 = 27.6, c2 = 38°C. T was arbitrarily chosen as a reference
00temperature. The shift can be referred to 1nother temperature, To, by replacingSthe constants in E(4) by new constants EI and 2(16)
c62 = c 2 + 'f -T 0 ()[~=o
When the glas-transition is taken as a reference, we find that T = T = -520 C ( )•0 g
" a, = 21, Z2 = 500C. Above A°C no values for the shift factor aT were available;
according to Williams, Landel and Ferry (10), the equation for the shift factor
holds up to 100°C above T . As a consequence, an extrapolation up to +-40°C should
be justified.
'&hen the curve mentioned before, representing the relationship betimen Lb,
T b tb and T, is projected onto the b, Eb -plane we obtain the so-called failure-
envelope. This is shown for the four materials under investigation in Fig. 15. A
rather large spread is observed, but this is not unusual for Tnis type of investi-
gations (1). Fig. 16 gives the upper part of the failure-envelope, in which
different symbol fillirgs are used for the four different temperatures in order
to show each temperature dependence. The impression is that measurements belonging
to one temperature lie on straight lines nuiking a fixcd slope, around unity, with
the axis. This may be explained as follows. Each stress-stra•i cuirve makes a slope
of around unity near the rupture point and the stress-strain curves of all
experiments are very much alike. Rupture eccurs at iarious positions along this
curve, resulting in the observed scatter. For ir,.retsing filler content, tie
stress-strrir cur_,-es become more horizontal at their end and the rupture points
lie more on a horizontal line.
1,L-
CENTRAAL LABCATORIUM TNO - DaaTL, Holland, Report No. CL 67/34 page 12.
The two other projections of the curve are shown in Pigs 17 and 18. According
to Eq.(4), time and temperature are interrelatr'd. Therefore, the horizontal scale
in Figs 17 and 18 is at the same time a scale for a reduced temperature. The time-
temperature relationship is not a simple expression; for reasons of simplicity we
only indicated at the horizontal axis the temperature for a rupture-time of 60
seconds. As in our measurements the variations in strain rate were rather small,
points referring to the same temperature tend to cluster.
It was mentioned earlier that shape and level of the curves show a spread of
about 3CP. As can be seen from Rig. 18, materials with 0 and 45j filler differ a
factor of 2 to 10 in rupture strain. The magnitude of this effect is well beymnd
the experimental spread. It may be concluded that the deformation at rupture
decreases with increasing filler content.
The stress-at-break, q0, is not subject to geometrical errors. Comparing the
W; and 4%. filled materials, we observe a decrease of a factor of 5 at low and a
factor of 2.5 at high temperatures. The highest value for the unfilled material
is 5 x 107 N/m2. This value is in accordance irith corresponding values given in7~ 2
the literature: ob = 4.4 x 107 N/m2 for a natural rubber vulcanisate (11) and
ab = 3 x 10 7 N/m 2 for SBR rubber (1 3).
At Columbia University, New York, tensile tests were performed on similar
materials (9). Up to dewetting the curves are similac, but thereafter rupture was
found at much lower strains, obviously because specimens of another shape were
used which gave more stress concentrations in the clamps than the type of dumb-
bell used in our investigation. Therefore, a comparison of these results with ours
had to be restricted to the dewetting phenomenon and was not extended to the
ultimate rupture properties.
4.4. Dewetting.
The maximum in the stress-strain curve is ascribed to dewetting; it coincides
with bl~uwching of the specimen. Dewetting i' the failure of the rubber around the
particlos, or breakage of bonds between rubber and particle, Vacuoles are formed
and the volume of the specimen increases suddenly (3). If this process in due to a
failttre of the rubLer, dewettijV, should have the sane time and temperature
dependence as failure of uz'illed ublir. Therefore, w.o investigated the relation-
The ratio of s=illest to l':revst brbdth, b2/b 1 , I a I5 in our, and 1.5 in Columbia'ein.venig •at iono.
|1
CENTRAAL LABORAT'ORIUM TNO - DELUT, Holland, Report No. ( L 67/34 page 13.
ship between dewetting time t deformation at dewetting d , and stress-at-dewetting
S ad in the same way as was done for the rupture properties. For practical reasons
it was assumed that the maximum in the stress-strain curve represents the breakager of this intergranular rubber, although this breaking goes on beyond the yield
point. Because the most pronounced maxima were found for the highest filler
concentrations, the investigation was restricted to these materials. Results are
indicated b, crosses in Figs 19 and 20. In the same diagram, broken lines, copied
frcu Figs 16 and 17, are drawm, corresponding to specimen rupture. Also inserted
are results from the literature, namely: dewetting maxima from tensile tests at
high strain rates (9), and rupture stresses from tensile creep experiments (8).
Upon studying Figs 19 and 20 it will be evident that the dewetting stress, adt
depends in the same way on the reduced rupture time as the breaking stress, ab,
for an unfilled material; apart from the dewetting stresses of the 45, filled
materials being a factor of 4 lower than the bre~ing stresses of the unfilled
material. The same holds for the deformation which appears to be a factor of 20
lower than for the unfilled rubber. These differences can easily be understood,
"because the strain in the rubber between the particles is much greater than the
"macroscopic strain. T.L. Smith (17) derived an expression for the ratio of yield
and rupture strain:
Ed/Cb = 1 - 1.105 c (6)
in vhich c denotes the volume fraction of the filler; at c = 45%, thdi equation
predicts a factor of about 0.15, vhich iz not ia contradiction ,.ith our findings.
We conclude: becai~se the dewetting phenomenon deponds on time and tempera-
tur*e in the same wny as do the ultim,%te proierties of the rubber matrix, we are
very probably concerned wiith a urocess of failure in the ribber itself rather
than a faihlu'e nf Zondo betwetn rbbcr and particle.
Inae-endent evidenoe for t-i, vi:e:point was obtained from mi.croscopic ob-
serv. tions• otr ,a e ditetted salt-ivirticles fdle,,n from the broken specimen.
'Jhen weter ":as adkiod, it vis soo, ti- t the salt particle dissolved but that some
inrsolull'e tieces %t,:tirved, v r', U.y pirces of rubber, which orig/inally adhered
to the : o:e of iv zi cryodl. Onlyv part o0' the surface appeared to be
covered -tth it ur'H'tr. Thih irnve:,tigsitiun is still in progress.1!1
COMTRAA LAOCRATORIUM TI0 DEISTp Hell-alp Report; No. 67/34 pg 4
SOberth and Bruonr(r , came to the same conclusior, when they subjected
polyurethane specimens in which a single steel ball of 3 mm diameter was imbedded
to tensile tests: the rubber is the deterimining factor in the deiretting phenomenon.
4.5. Comparison with cr -p co:P:.ments performed previously.
Tensile creep experiments, up to failu.xe, on filled rubbers were reported in
Technical Report no. 5 (8), In a creep test, the specimen is bubjected to a
constant tensile force, which means that the stress is constant or slightly
increasing during the test. in a stress-strain test, the strain rate is practi-
cally constant so that the stress may vary and exhibit the maximum in the stress
mentioned earlier. For a creep test, the cc.2igurwtion after deiretting is more or
less unstable, resulting in a shz--p i-nroase in strain rate after dewetting.
From Fig. 5 it follows that the largest stress for a highly fil.led material
is the dewetting stress; a creep test with this material consequently measures
the dewetting stress. For lowrer filled materials the highest stress is the stress-
at-break, as can be seen from Figs ?. 3 & 4o This is the same stress which is
found in thi± creep experiment. This distinction is not of much practical impor-
tance since (see Fig. 19) it is obvious that, after the time-reduction, ad and
fall on the same curve.
The results obtained from the creep measurements as reported ea• ier (8) are
inserted in Figs 19 and 20. The agreement is -ather good dcspite the fact that
the type of deformation in both cxperiments is different. Moreover it should be
noted that specimen dimensions and shapc•; were diffcrent, Because the particle
size was not small with respect to the cross section, shape influences are likely
to appear.
C9E1TRAAL LABORATORIUM TNO - DELFT, Holland, Report No. CL 67/34 page 15.
5. CONCLUIONS.
I* When the filler content of the filled polyurethane rubber increases from 0 to
S45%1 by volume, the rupture stress decreases by a factor of 5 at low and by a
factor of 2.5 at high temperatures; the rupture strain decreases by a factor
[ of 2 to 10.
2. The theory of the failure envelope could be applied to the rupture properties.
3. The stress-strain curves of materials with 45/ filler show a maximum at
strains of about 2Q,,. The maximum is explained by assuming dewetting of the
particles in the matrix.
1 4. The dewetting maximum is temperature and strain-rate dependent, in the same
way as the ultimate properties of the unfilled rubber. This lends support to
the view that dew'etting is a failure of the rubber between the filler particles,
and not a failure of the bond between rubber and filler particles, nor a
I failure of the filler particles themselves.
II
I
I
I
CENTRA"i LABORATORIUM TNO - DELFT, Holland, Report No. CL 67/34 page 16.
6. REFERoCES.
1. F.R. Schwarzl Mechanical Properties of Highly Filled Elastomers,
Technical Report No. 1, Central Laboratory TNO,
Delft, July 1962.
2. F.R. Schwarzl Mechanical Properties of Highly Filled Elastolers
II, Influence of particle size and content of
filler on tensile propertles and shear moduli,
Tech•ical Report No. 2, Central Laboratory TNO,
Delft, April 1963.
3. P.R. Schwarzl Mechanical Properties of Highly Filled Elastomers
III, Influence of particle size and content of
filler on thermal expansion and bulk moduli,
Technical Report No. 3, Central Laboratory TNO,
Delft, June !964.
4. F.R. Schwarzl, H.W. Bree and Mechanical Properties of Highly Filled Elastomers
C.J. •ederveen I, Proc. 4th Int. CongrT. Rheology (Providence,
1963), E.H. Lee (Ed.), Interscience/wiley, N.Y.
(1965) Vol. 3, 241-263.
5. C.11. van der Wal, Mechanical Properties of Highly Filled Elastmers
H.W. Bree and F.R. Schwarzl II, J. Appl. Polymer Sci. .2 (1965) 2143-2166.
6. F.R. SchvTarzl et al. On Mechanical Properties of Unfilled and Filled
Elastomers, Proc. Fourth Symposium on Naval
Structural Iecimnics, A.C. iringen, H. Liebowitz,
S.L. Kok, J.K. Crowley, Editors, Pergaman Press
1967, Neir York pp 503-538.
7. H.W. Bree, F.R. Schwarzl and Mechanical Properties of Iihly' Filled Elastomers
L.C.E. Struik IV, Influence of particle size Wd content of
filler on tensile ('reep at lar"ve deformations,
Technical Report No. 4, Central Laboratory TNO,
Delft, July 1q65.
CELTRAAL LO3ALTORIUM TNO - DME1'i, Holland, Report No. CL 67/34 page 17.
8. L.C.E. Struik, H.W. Bree and Mechanical Properties of Highly Filled
F.R. Schwarzl Elastomers V, Influence of filler characteris-
tics on tensile creen at large deformations,
on rupture properties and on tensile strain
recovery, Technical Report No. 5, CentralrI Laboratory TNO Delft, April 1966.
9. T. Nicholas and The effect of Filler on the Mechanical
A.M. Freudenthal Proporties of an Elatitwer at high strain
rates. Tecliical Report -To. 36, Columbia Univeisity,
Departient of Civil jn,•ineering and Engineering
Iechanics, Neir York, November 1 366.
10. M.L. Williams, R.F. Landel and J. Amer. Chem. Soc. JZ (1955) 3701-3707.
J.D. Ferry
11. T.L. Smith J. Applied Plhvsics M (1964) 27-36.
12. T.L. Smith J. Polamer Science Al (1963) 3597-3615.
13. J.C. Halpin J. Applied Physics 55 (1964) 3133-3141.
14. J.C. Halpin and F. Bueche J. Applied Physics 35 (1964) 3142-3149.
15. R.F. Landel and R.F. Fedors Rupture Amorphc'is Unfilled Polymers in
"Fracture Processes in Polymeric Solids",
Ed. B. Rosen Interscience, New York, 1964,
pp 3&1-485.
16. F.R. Schc-arzl in Houvink/Staverman, "Chenie und Technologio
der Kunststoffe I, Akademische Verlasgesell-
schaft Oieest & Fortig K.-G. Leipzig, 4. Aufl
17 , 7 4'. . am,• th ? . u .S • livol . 3 (1,'];5 •) 11 ")- 136 .
18. A.E. O~ertýý ttnd :{:.':,•,: •:::.30•. 40,o0l. 1i(' 6%) 5-1650
eL
I
CENTRAAL LABORATORIUI4 TNO - DELFT, Holland, Report No. CL 67/34 page 18.
CATONNT FIGRES.
Fig. 1 Shape and dimensions, in mm, of the specimens used for stresd-strain testing.
Fig. 2 Stress-strain diagrams of unfilled polyurethanes at different
temperatures and strain rates as indicated.
Fig. 3 Stress-strain diagrams of polyurethane rubber filled with 15 vol%
of sodium chloride particles of 0.1 mm at different temperatures
"and strain rates as indicated.
Fig. 4 Stress-strain diagrams of polyurethane rubber filled Aith 30 vol0
of sodium chloride particles of 0.1 mm at different temperatures
and strain rates as indicated.
Fig. 5 Stress-strain diagrams of polyurethane rubber filled with 45 vol}i
of sodium chloride particles of 0.1 mm at different temperatures t
and strain rates as indicated.
Fig. 6 Stress-strain diagrams of a polyurethane rubber filled with
various amounts of sodium chloride particles of 0.1 mm at +30 C.
Fig. 7 Stress-strain diagrams of a polyurethane rubber filled with
various amounts of sodium chloride particles of 0.1 mm at OC.
Fig. 8 Stress-strain diagrams of a polyurethane rubber filled with
various amounts of sodium chloride particles of 0.1 mm at -20°C.
Fig. 9 Stress.-strain diagrams of a polyurethane rubber filled with
various ioiomts of sodiua chloride particles of 0.1 mm at -30oC.
Fig. 10 StresL-strJain diagrams of a polyurethane rubber filled itith
various amounts of soditun chloride particles of 0,1 mm at -35 C.
Fig. 11 Stress-strain diagrams of a polyurethnite rubber filled with
various maounts of sodium chloride particles of 0.1 :-n at -400 C.
Fig. 12 Stress-strain diagrams of a polywetthaio rubber filled with
various amounts of sodium chloride particles of 0.1 mm at -45 0 C.
CETMUU IABOBATORIUM TNO - DELT, Holland, Report No. CL 67/34 page 19.
Fig. 13 Young's modulus E as a function of temperature as found fromvarious tests.
r Fig. 14 Time-temperature shift function a_ vs temperature for polyurethane
rubbers filled with various amounts of NaCi. Reference temperature
is -35 0C. The drawn line is a curve calculated according to Eq.(4)
with c = 27.6 andc = 38C.1 2=
"Fig. 15 Failur-e envelopes for polyurethane rubbers filled with 0, 15, 30
and 45 vol5/ of sodium chloride particles of 0.1 mm.
Fig. 16 Same as Fig. 15, upper part of the curves.
Fig. 17 Reduced rupture stress vs reduced rupture time for polyurethane
rabbers filled writh 0, 15, 30 and 45 vo1o of sodium chloride
particles of 0.1 mm.
Fig. 18 Elongation at rupture vs. reduced rupture time for polyurethane
rubbers, filled with O, 15, 30 and 45 vol5U of sodium chloride
particles of 0.1 mm.
Fig. 19 Diagram of reduced stresses as a function of reduced rupture time.
Plotted are rupture stresses obtained from Fig. 17, and from creep
experiments, as well as detetting stresses.
Fig. 20 Diagram of elongation vs. reduced rupture time. Plotted are
elongation at rupture obtained from Fig. 18, and from creep
experiments, as well as elongation at dewetting.
Delft, 12 juni 1)t)7Nei IV
TAOE I , COId08ITION AnD PROIPTIES OW NaCl-FILLD SAMPLES PREPARED._ _.. ,• ,-_ ,. __ -- :
1 2 3 4 5 6 7 8 9
batch no. Compcsition prepolymer filler coutont fraction NaCl-fiLer eS/i00 g polyether vol % Nami no. particle (o vo
Deamophen 3600 from from size ahloroS.I Tn D- d-JAM d form
dientr
3600/283 19.6 4.0 4.0 400
3600/284 19.5 4.0 4.0 402
3600/286 19.6 4.0 2.5 404
3600/288 19 6 4.0 2.5 400
3600/289 19.6 4.0 2.5 401
W600/290 19.5 4.0 2.5 - 401
3600/315 19.6 4C0 3A4 29.3 29.8 4 90-105 365
3600/316 19.6 4.0 3.4 29.3 29.7 376
3600/317 1).6 4.C 3.4 29.3 29.8 375
3600/318 19 5 4.0 3-4 29.3 29.9 370
3600/319 19.6 4.0 3.4 29.3 29.7 390
3600/320 19.6 4.0 4.6 14.5 14.8 383
3600/321 19.5 4 0 4.6 14.5 14.8 379
3600/322 19.6 4.0 4.6 14.5 14.8 391
3600/323 19.5 4.0 4.6 14.5 14.8 385
3600/324 19.6 4.0 4.6 14.4 14.8 395
3600/325 ' 19.5 4.0 4.6 14.5 14.9 400
3600/326 19.6 4.0 3.4 29.3 29.7 383
3600/27 19.6 4.0 2.6 44.4 45.0 38646•0/328 19.5 4.0 2.6 44.4 45.2 393
3(00/3n 19,6 4.0 2.6 4.4 45,C 396WSC,,13!0 19.6 4.0 2.6 44.4 45.2 392
3600/331 19.5 4.0 2.6 44.3 45.1 394
3600, 3 19.5 4.0 2.6 44.3 45o2 . 38
•im. pW 20.
7 8 9 10 1 12
-action XaCl-filler swe.ling 230 C d/"A temperatureno. particle (, vol.increase) /cmI) of testsize chloro- trichloro- 200C OCJm form etI.ylene
400 306 1,067 +30
402 306 1.067 +30
404 305 1.067 +300310 1.067 0, +30
401 305 1.067 -45, -40, -35, -30, -20, +30
401 307 1.067 +30
4 90-105 365 287 1.398 -30, -20, +30
376 289 1.397 -40, O, +30
375 285 1.398 -45, -35, +30
370 285 1.399 +30
390 290 1.397 +30
383 295 1.235 +30
379 289 1.235 +30
391 300 1.236 +30
385 299 1.235 -45, -35, +30
395 302 1.236 -40, O, +30
400 304 1.237 -30, -20, +30
383 297 1.397 +30
386 290 1ý563 +30
393 291 I 565 +30
396 292 1.563 +30
392 237 1.566 -45, -35, +30394 297 1.564 -45, -40, -30, -20, O +30
398 299 1.566 -20, +30
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4,5 °/o ~t , T
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.0- -- - __ .. . . . _
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Nn V_______ _____._.____ ______
I Failure envelopespolyurethane rubber
- 1- -- NatCl 90-105AMm.0 %/ NaCt
2 00 ,
i00
10_ 10 1000. al9015um - t
• ,.-t---Fig 15" 15 , . .
* It I IllII _ D
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.. .~. .. ......
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10 I0 101
~ !kjint ~a'~SkaIonDOCUMENT CONTROL DATA - R & D
i$e.-irir1 0a$1,JI1-rfatiQn it tirmt, _body o( obtfUat and indv~ng4 .on~ogatijnn flifit -fir entered when the overall report Is reMxilWfcd
-}I. oRMGNATP.G ACFi@TY (Corporaro, author) 2.. RILPOAT SECURITY CLASSIFICA110H
Ceta lbrtry~O-Delft Unclassified2b. GROUP
!0Ooh~roal- Propartieo3 of Highly Yill~d Elastoirors VI. LhlfUence Of fillor contont
=.d tetporrtturo onltm te tnsilo properti~s.
4. O9SCAIWtIiV NOTES (Trp of report *ftditlusivfe dotes) TCJC1~p~ o
I j AU T94OR431 (rfr8Ue na , Midddt Itmttal, 102!< not"e)
_Yeddivoon, Cornelius Jo
*.REPORT OATE ?a. TOTAL. NO. OF PAGES 7b. NO. OF REFS
Juno 196720141a. CONTRACT OR GRANT NO. 98. ORIGINATOR'S REPORT NUMBERISI
NT 62558 ~cnc1~pr ob. PROJECT NO
e"mclRprno6
4375
C. 9b. OTHER REPORT NOISI (Ainy other numbers that may be aissignedthog report)
CL 67/34
10, OIStRIOUTION STATEMAENT
Distribution list for iinclacssirio I., ncl eors
II. SUPPLEMENTARY NOTES 12. SPONSORING MILITARY ACTIVITY
Office of .. vlal ýv. .joarc'.:
13I. A9SAIRACT
Rcmuit's zr presentecd of -tr.ostrlk1; 13 ~)or:,.xr,.ed at vcarioua~t~r~c n
* strain r'ater, on materials, filed -zdth v:.-xiLou =,Uunts Of Socilu'. , 12.oride --.tic"ez on t
arAcx _110'1. 011001 0.1 L;z!. Stros, ;ýad st~nat ra.i.urc o erun~" widthiu :o'Coaoktcent. F'or oach ,1~.(!tr~lia.1.~xt it 1was possiblo to oormtzac'ý Lhc~i l-(zafbonvolopa by -e-nim n2 vwhicki thc ~sut -could be doocrdbcd adcquav'X`L,y6
-CŽ dmo ettT' of. the ps)ati.Olco .Lr, lclx aabbe.-y %..aturixq o.t~L. in The strion-on'rain. alzmo,p I o c'.Cril-bz" to fai2.urc '"'.0 ~ .e''
~~~C "z -.d no'- t~ al.o o2r 0., i 1r-It buccnu-c "10 dcwttin . ."La:w
de~i Oil.t on ,.pertU1r 11U1 tl:.O inl tlQ -,=10 way' .13 hao rulajtwuro o:Tt.
lv- re-outo aar, ý,onp.acd w-Ith ctxarliciv xoo',i,:tionng o,,-. hi~1h a~'oend tom. . tvc.
u.. ~opoxperiment..;p and a g~ocd camumant '~oundo
FORM (AGE 1
D ,Novi J 47
3/ 10-01611Nrm1 Ut~w~