- Email: [email protected]
Translational and rotational mobility of low molecular weight substances in the plasticized polyvinyltrimethyl silane
2898
15. 16.
17. 18.
V. V. BARANCHEYEVA et aL
V. A. MOROZOV, Vysokomoi. soyed. AI6: 1551, 1974 (Translated in Polymer Sci. U.S.S.R. 16: 7, 1796, 1974) Yu. A. OL'KHOV, Yu. B. KALMYKOV and S. M. BATURIN, Vysokomol. soyed. A26: 1681, 1984 (Translated in Polymer Sci. U.S.S.R. 26: 8, 1880, 1984) L. T. KASUMOVA, Yu. B. KALMYKOV, Yu. A. OL'KHOV. S. M. BATURIN and S. G. ENTELIS, Vysokomol. soyed. AI9: 2575, 1977 (Translated in Polymer Sci. U.S.S.R. 19: 11, 2968, 1977) T. E. LIPATOVA, V. K. IVASHCHENKO and L. L BEZRUK, Vysokomol. soyed. AI3: 1701, 1971 (Translated in Polymer Sci. U.S.S.R. 13: 8, 1913, 1971) A. Ye. NESTEROV, T. E. LIPATOVA, S. A. ZUBKO and Yu. S. LIPATOV, Vysokomol. soyed. A12: 2252, 1970 (Translated in Polymer Sci. U.S.S.R. 12: 10, 2553, 1970)
Polymer Science U.S.S.R. Vol. 28, No. 11, pp. 2698-2703, 1986 Printed in Poland
0032-3950/86 $10.00+ ,00 C) 1987PergamonJournals Ltd.
TRANSLATIONAL AND ROTATIONAL MOBILITY OF LOW MOLECULAR WEIGHT SUBSTANCES IN THE PLASTICIZED POLYVINYLTRIMETHYL SILANE* V. V. BARANCHEYEVA, l. I. BARASHKOVA, S. G. DURGAR'YAN, N. E. KALYUZHNYI, YU. P. YAMPOL'SKII a n d Y u . G. Y'ANOVSKII Topchiyev Institute of Petrochemical Synthesis, U.S.S.R. Academy of Sciences Chemical Physics Institute, U.S.S.R. Academy of Sciences
(Received 12 April 1985) The coefficients of diffusion of hydrocarbons and the rotation frequencies of spin probes plasticized with oligovinyltrimethyl silane (M=600) have been measured. Plasticization results in a monotonic reduction in the glass transition temperature from 170 to 60 ° for a sample containing 43 % of the oligomer. The general character of dependences of the translational and rotational mobilities of various types of low molecular weight substances on the plasticizer concentration has been determined.
MUCH STUDYhas been made of the permeability of plasticized polymer~ [1], but considerably less information is available on coefficients of diffusion of gases in plasticized polymers [2-4]. Our aim in the present work was to determine the influence of the concentration of plasticizer on the glass transition temperature Tv the diffusion coefficients D for hydrocarbons and the rotation frequencies v (the rotational diffusion coefficients) of spin probes in polyvinyltrimethyl silane (PVTMS) plasticized with oligovinyltrimethyl silane * Vysokomol. soyed. A2& No. 11, 2426-2429, 1986.
Translational and rotational mobility of low molecular weight substances
2699
(OVTMS). When the plasticizer is an oligomer whose chemical nature is akin to that o f the polymer, mixtures o f the two will be thermodynamically compatible, i.e. it is possible in this way to eliminate (or minimize) the extent to which a role could otherwise be played by the chemical nature of a plasticizer, and by its microheterogeneity. Study objects in the present investigation were PVTMS (M= 6 x 105, plasticized with OVTMS (M= 600). Films were cast from a solution of PVTMS and OVTMS in toluene; traces of the solvent were removed by prolonged evacuation at 60° (to constant weigh0. The mass spectrometric method outlined in [5] was used to determine the diffusion coefficients D. The D values were determined at 22 + 1°, the pressure up to the membrane being 5-50 kPa, and, after the membrane, < 1 Pa. In this pressure range diffusion coefficients are normally unrelated to diffusant concentrations, i.e. the coefficients characterize polymer--diffusant systems under conditions of infinite dilution. The determination accuracy for D was ~20%. The film thickness was in the interval 100-200 am. Nitroxyl radicals of two types: NOz )NO.
0
\ / - -
/N, I
,--<'NO •
/% II
were used in this study of plasticized PVTM$ carried out with the aid of spin probes. Probe I was introduced into the membranes from vapours, and probe II from solution in acetone; painstaking elimination of the solvent (to a constant spectrum) was carried out. The statistical error in determination of rotation frequencies for the probes was ~ 5 ~.. ESR spectra were measured at 25°. A standard method [6] was used to determine rotation frequencies for the probes. Glass-transition temperatures were determined by a dynamic method, using a DKhP type mechanical spectrometer under conditions of low-amplitude periodic shear deformation (frequency of forced sinusoidal vibrations ~ 1 Hz, rate of temperature variation 2 deg/min). Figure 1 shows the concentration dependence of Tg determined from the mechanical loss peak, tan Omax.It can be seen that there is a marked fall in T, when a small amount ot plasticizer is added. A further increase in the OVTMS is accompanied by a more gradual reduction in T s. Even for the sample containing the highest concentration of O V T M S (43 %) the glass-transition temperature still remains above r o o m temperature, i.e. the studied samples were all in the region of the glasslike state. In Table 1 we have D values for hydrocarbon gases relative to plasticizer concentrations in the membranes. It is seen that dependences of D on OVTMS concentrations are identical for the various hydrocarbons o f differing MW. Up to c = 2 % D values are constant within the measurement accuracy limits. Where c = 4 3 % , corresponding to T , = 6 0 °, the D values are higher. It is seen f r o m Fig. 2 that the plasticizer concentration has only a slight influence o n permeability coefficients for hydrocarbons in PVTMS. This is apparently due to high values of the permeability coefficients in the case of the plasticized PVTMS, the values being higher by several orders c o m p a r e d with those for polymers where plasticization leads to a marked increase in gas permeability values (PVC, P C T F E a m o n g others) [1]. No superposition o f the spectra of paramagnetic radicals with various rotation
2700
V.V. BARANCmSYS'VAet al.
frequencies is seen for any of the samples of plasticized PVTMS containing spin probes on analyzing the ESR spectra. This is one further fact substantiating the thermodynamic compatibility of PVTMS and OVTMS. The data in Table 2 show the influence of the plasticizer concentration on the spin probe rotation frequency. It can be seen that for small molecules in the plasticized polymers there are identical dependences for the translational D and the rotational mobilities: the v values are constant where c= 0-25 ~o; on further increasing the plasticizer concentration there is increased mobility. It should be noted that molecular volumes for probes I and II differ very significantly, and accordingly there is a difference amounting to one order in their rotation frequencies. However the onset of variation in the rotation frequency appears at one and the same plasticizer concentration (or at the same value of T=) irrespective of the size of the probe.
Tzgo °I
P/ Po
xl o2 *3 zx4
X
8
x O A
×
I
zo FIG. 1
4o c, wt%
o
20
I
40 c, wt.%
FxG.2
FIo. 1. Dependence of the glass-transition temperature Tg on the plasticizer concentration c in the PVTMS-OVTMS system. Fio. 2. Influenceof the OVTMS concentration on the permeability coefficientsfor methane (1), acetylene (2), ethane (3) and allene (4) through membranes based on the plasticized PVTMS, according to data in [7]. To investigate whether a role could be played by plasticizer-induced crystallization [4] X radiograms were obtained for the plasticized PVTMS and (for comparison) for PVTMS without OVTMS. An analysis of the X-ray data shows that all the studied samples are structurally amorphous. Thus it appears that addition of the plasticizer to PVTMS is unaccompanied by any crystallization. It is known from the results of earlier studies [7, 8] that translational diffusion coeti~cients and spin probe rotation frequencies for polymers withdifferent glass-transition temperatures vary in similar ways with variations in T= and there is agreement between the actual D and v values. It is clear from the results of the present work that the same is no less true for the plasticized polymers and the correlations between D and v hold with greater accuracy than for polymers of other types. This substantiates an earlier conclusion that spin probes and gas molecules yield data on identical dynamic and structural peculiarities of polymers. It is known that attempts have been made to relate the mobility of low molecular weight particles in glasslike polymers (particularly those with high glass-transition
Translational and rotational mobility of low molecular weight substances TABLE 1. DIFFUSION COEFFICIENTS FOR THE e t . A s ~ z ~
2701
PVTMS
D x 10 7 ( c m 2 . s e e - 1 ) , at O V T M S concentrations (~,) Gases
0 0. 78 0.13 0.18
Acetylene
Ethane Allene
5.4 0. 79 0.14 0.19
20.8 0. 80 0.12 -
25-1 0. 84 0.15 0-22
43-0 1"35 0"38 0-37
TABLE2. ROTATIONFREQUENCIESFOR SPIN PROBESIN THE PLASTICIZEDPVTMS Probes I
II
0 7.5 0.91
v x 108 (see-1) at OVTMS concentrations (~0) 5-4 I 20.8 25.1 7.2 8.2 7.6 0.91 0.77 0-77
43.0 10.4 1.05
temperatures) to the absence of thermodynamic equilibrium states in glasslike polymers. To support this viewpoint reference has been made to free volume theory, i.e. considerations pertaining to the latter were transferred to the glasslike state [10]. On the other hand some authors have endeavoured to relate mobility in glasslike polymers to smallscale movements [11-14] detectable by N M R methods [6]. The introduction of a plasticizer and a change in the glass-transition of a glasslike polymer will invariably be reflected in its nonequilibrium state (at some given temperature) becoming less marked. As regards small-scale movements, the introduction of a plasticizer may n o t only facilitate, but also impede the latter (the antiplasticization effect), a view that is substantiated by the N M R data obtained with a sample rotating at the magic angle [4, 15]. Data obtained by studying the influence of plasticizer concentration on the diffusion of low molecular weight substances in polymer could well shed light on the role played by both these factors. The influence ofthe plasticizer concentration may be examined for three independent quantities, firstly for coefficients of diffusion of gases and vapours D in plasticized polymer (as reported for the system cellulose nitrate-low molecular weight polyethyleneglycol [3], for PVC-tricresylphosphate [4] and for PVTMS plasticized with dioctyl sebacate and OVTMS (as in [2] and in the present investigation)); secondly, we have the spin probe rotation frequencies v (PVTMS, plasticized with OVTMS (as in the present work)), and thirdly, we have the 1/7"1 relaxation rates (in PVC, based on t h e data obtained by 13C N M R [4]). It was found by innvestigation of all these quantities that the influence of the plasticizer concentration is identical in all the studied systems: in the casse of small concentrations there is a slight reduction, or no change, in the measured value up to a definite plasticizer concentration, after which an increase in the value is observed. While initial reductions in D and in 1/T could be attributed either to a diminution of the nonequilibrium free volume fraction or to the antiplasticization effect, the increase in D, v and 1/7;'1 is attributable solely to an intensification of the small-scale molecular mobility of groups in the polymer on condition that there is still a minimum appearing in the
2702
V. V. BARANCHEYBVAet al.
glasslike region. Otherwise it would have been possible to say that the increase in these values could have been due to the development o f segmental mobility in the polymer. It appears from Fig. 1 and f r o m Tables 1 and 2 that the onset o f rises in D and v in the plasticized PVTMS occurs in the region of the glasslike state for a sample whose glass-transition temperature is higher (by ~ 40 °) than that at which measurements were carried out. F r o m a qualitative standpoint one m a y draw the same conclusion for plasticized PVC for which rises in D and in 1/I"1 were reported for a ~ 15% plasticizer concentration [4]. Thus it appears f r o m a study of the results reported in papers [2-4] and from those obtained in the present work show that at first sight there would seem to be c o m m o n factors underlying changes observed in quantities such as D, v and 1/I"1 for different plasticized polymers. In addition, the results o f a study o f the character o f the mobility o f low molecular weight particles in glassy polymers would indicate that these findings cannot be attributed solely to the nonequilibrium state o f the latter without at the same time taking account of the role that could be played by small-scale motions occurring in these polymers. The authors thank S. A r t a m o n o v for kindly carrying out the X ray analysis o f the plasticized polymers.
Translated by R. J. A. HENDRY REFERENCES
1. D. W. BRUBAKER and K. KAMMERMEYER, Industr. and Engng. Chem. 44: 1465, 1952 2. D. W. BRUBAKER and K. KAMMERMEYER, Industr. and Engng. Chem. 45: 1148, 1953 3. S. A. REITLINGER, Pronitsayemost' polimernylda materialov (Permeability of Polymeric Materials), p. 173, Khimiya, Moscow, 1974 4. A. L. YEVSEYENKO, V. V. TEPLYAKOV, S. G. DURGAR'YAN and N. S. NAMETKIN, Vysokomol. soyed. B21: 153, 1979 (Not translated in Polymer Sci. U.S.S.R.) 5. M. KAWAKAMI, H. IWANAGA, Y. HARA, M. IWAMOTO and S. KAGAWA, J. Appl. Polymer Sci. 27: 2387. 1982 6. M. D. SEFCIK, J. SCHAEFFER, F. L. MAY, D. RANCHER and S. M. DUB, J. Polymer Sci., Polymer Phys. Ed. 21: 1041, 1983 7. ye. p. YAMPOL'SKII, E. G. NOVITSKII and S. G. DURGAR'YAN, Zavod. lab. 46: 256, 1980 8. L. I. ANTSIFEROVA, A. M. VASSERMAN, A. N. IVANOVA, V. A. LIVSHITS and N. S. NADEMETS, Atlas spektrov EPR spinovykh metok i zondov (Atlas of ESR Spectra for Spin Labels and Probes). p. 159, Nauka, Moscow, 1977 9. Yu. P. YAMPOL'SKII, S. G. DURGAR'YAN and N. S. NAMETKIN, Dokl. AN SSSR 261: 708, 1981 10. Yu. P. YAMPOL'SKII, S. G. DURGAR'YAN and N. S. NAMETKIN, Vysokomol. soyed. A24: 536, 1982 (Translated in Polymer Sci. U.S.S.R. 24: 3, 592, 1982) 11. D. R. PAUL, Ber. Bunsenges. phys. Chem. 83: 294, 1979 12. A. Ye. CHALYKH, S. A. NENAKHOV, V. A. SALMANOV, S. S. MIKHAILOVA, S. N. TOLSTAYA and A. N. KHODAN, Vysokomol. soyed. A19: 1488, 1977 (Translated in Polymer Sci. U.S.S.R. 19: 7, 1706, 1977) 13. R. G. PACE and A. DATYNER, J. Polymer Sci. Polymer Phys. Ed. 17: 437, 1979 14. R. G. PACE and A. DATYNER, J. Polymer Sci. Polymer Phys. Ed. 17: 453, 1979
2703
Films of PC-PAASO block copolymer blends
15. R.G. PACE and A. DATYNER, J. Polymer Sci. Polymer Phys. Ed. 17: 465, 1979 16. R. G. PACE and A. DATYNER, Polymer Engng. Sci. 20: 52, 1980 17. J. SCHAEFER, M. D. SEFCIK, E. O. STEFKAL, R. A. MeKAY, W. T. DIXON and R. E. CAIS, Macromolecules 17: 6, 112, 1984
0032-3950/86$10.00+.00 ~) 1987PergamonJournalsLtd.
Polymer Science U.S.S.R. Vol. 28, No. 11, pp. 2703-2709,1986 Printedin Poland
SELF-BLUNTING OF N O T C H E S IN F I L M S OF POLYCARBONAIY_,-POLYARYLATEARYLENE S U L P H O N O X I D E BLOCK C O P O L Y M E R B L E N D S * V. N. SHOGENOV,G. V. KOZLOV, M. A. GAZAYEVand A. K. MIKITAYEV High Polymer Institute attached to the Cabardino Balkar State University
(Received 16 April 1985) Films of polycarbonate-polyarylatearylenesulphonoxide block copolymer blends underwent stretching, the samples each having a sharp notch. Stretching of the samples with a definite make-up of the blends showed that the rupture stress increases with the increase in the notch length. This was explained with the aid of a model of crack self-blunting by plastic deformation. The degree of self-dulling increases with the growth in the forced elasticity stress.
Is SOLIDpolymers, particularly in film subjected to stretching under conditions where the latter are in horizontally stressed states a major role is played by processes of plastic (or forced-elastic) deformation [1]. Factors influencing the amount of energy required for propagation of a failure-causing crack (particularly in the case of notched samples) may include the volume of the plastically deformed material, the notch parameters, and some others. This paper relates to our study of plastic deformation mechanisms leading to self-blunting of notches (stationary cracks) in film samples containing the polyarylatearylene sulphonoxide block copolymer (PAASO) [2] and blends of varying composition based on PAASO with a polycarbonate (PC) based on bisphenol A. PAASO is a polycondensation type polyblock copolymer, the chemicat structure being of type {[A]~- [B]m- [C]k}x, where
/
0
/ 0
II
/II
CHa
,~
I
A = [ - - C - - , / f l - ' ~ .C - - O - - / ' J - - ~ ' - - C - - / ~ - - ' \ \ - - 0 - - ~ CHa * Vysokomol. soyed. A28: No. 11, 2430-2435, 1986.
a-
15. 16.
17. 18.
V. V. BARANCHEYEVA et aL
V. A. MOROZOV, Vysokomoi. soyed. AI6: 1551, 1974 (Translated in Polymer Sci. U.S.S.R. 16: 7, 1796, 1974) Yu. A. OL'KHOV, Yu. B. KALMYKOV and S. M. BATURIN, Vysokomol. soyed. A26: 1681, 1984 (Translated in Polymer Sci. U.S.S.R. 26: 8, 1880, 1984) L. T. KASUMOVA, Yu. B. KALMYKOV, Yu. A. OL'KHOV. S. M. BATURIN and S. G. ENTELIS, Vysokomol. soyed. AI9: 2575, 1977 (Translated in Polymer Sci. U.S.S.R. 19: 11, 2968, 1977) T. E. LIPATOVA, V. K. IVASHCHENKO and L. L BEZRUK, Vysokomol. soyed. AI3: 1701, 1971 (Translated in Polymer Sci. U.S.S.R. 13: 8, 1913, 1971) A. Ye. NESTEROV, T. E. LIPATOVA, S. A. ZUBKO and Yu. S. LIPATOV, Vysokomol. soyed. A12: 2252, 1970 (Translated in Polymer Sci. U.S.S.R. 12: 10, 2553, 1970)
Polymer Science U.S.S.R. Vol. 28, No. 11, pp. 2698-2703, 1986 Printed in Poland
0032-3950/86 $10.00+ ,00 C) 1987PergamonJournals Ltd.
TRANSLATIONAL AND ROTATIONAL MOBILITY OF LOW MOLECULAR WEIGHT SUBSTANCES IN THE PLASTICIZED POLYVINYLTRIMETHYL SILANE* V. V. BARANCHEYEVA, l. I. BARASHKOVA, S. G. DURGAR'YAN, N. E. KALYUZHNYI, YU. P. YAMPOL'SKII a n d Y u . G. Y'ANOVSKII Topchiyev Institute of Petrochemical Synthesis, U.S.S.R. Academy of Sciences Chemical Physics Institute, U.S.S.R. Academy of Sciences
(Received 12 April 1985) The coefficients of diffusion of hydrocarbons and the rotation frequencies of spin probes plasticized with oligovinyltrimethyl silane (M=600) have been measured. Plasticization results in a monotonic reduction in the glass transition temperature from 170 to 60 ° for a sample containing 43 % of the oligomer. The general character of dependences of the translational and rotational mobilities of various types of low molecular weight substances on the plasticizer concentration has been determined.
MUCH STUDYhas been made of the permeability of plasticized polymer~ [1], but considerably less information is available on coefficients of diffusion of gases in plasticized polymers [2-4]. Our aim in the present work was to determine the influence of the concentration of plasticizer on the glass transition temperature Tv the diffusion coefficients D for hydrocarbons and the rotation frequencies v (the rotational diffusion coefficients) of spin probes in polyvinyltrimethyl silane (PVTMS) plasticized with oligovinyltrimethyl silane * Vysokomol. soyed. A2& No. 11, 2426-2429, 1986.
Translational and rotational mobility of low molecular weight substances
2699
(OVTMS). When the plasticizer is an oligomer whose chemical nature is akin to that o f the polymer, mixtures o f the two will be thermodynamically compatible, i.e. it is possible in this way to eliminate (or minimize) the extent to which a role could otherwise be played by the chemical nature of a plasticizer, and by its microheterogeneity. Study objects in the present investigation were PVTMS (M= 6 x 105, plasticized with OVTMS (M= 600). Films were cast from a solution of PVTMS and OVTMS in toluene; traces of the solvent were removed by prolonged evacuation at 60° (to constant weigh0. The mass spectrometric method outlined in [5] was used to determine the diffusion coefficients D. The D values were determined at 22 + 1°, the pressure up to the membrane being 5-50 kPa, and, after the membrane, < 1 Pa. In this pressure range diffusion coefficients are normally unrelated to diffusant concentrations, i.e. the coefficients characterize polymer--diffusant systems under conditions of infinite dilution. The determination accuracy for D was ~20%. The film thickness was in the interval 100-200 am. Nitroxyl radicals of two types: NOz )NO.
0
\ / - -
/N, I
,--<'NO •
/% II
were used in this study of plasticized PVTM$ carried out with the aid of spin probes. Probe I was introduced into the membranes from vapours, and probe II from solution in acetone; painstaking elimination of the solvent (to a constant spectrum) was carried out. The statistical error in determination of rotation frequencies for the probes was ~ 5 ~.. ESR spectra were measured at 25°. A standard method [6] was used to determine rotation frequencies for the probes. Glass-transition temperatures were determined by a dynamic method, using a DKhP type mechanical spectrometer under conditions of low-amplitude periodic shear deformation (frequency of forced sinusoidal vibrations ~ 1 Hz, rate of temperature variation 2 deg/min). Figure 1 shows the concentration dependence of Tg determined from the mechanical loss peak, tan Omax.It can be seen that there is a marked fall in T, when a small amount ot plasticizer is added. A further increase in the OVTMS is accompanied by a more gradual reduction in T s. Even for the sample containing the highest concentration of O V T M S (43 %) the glass-transition temperature still remains above r o o m temperature, i.e. the studied samples were all in the region of the glasslike state. In Table 1 we have D values for hydrocarbon gases relative to plasticizer concentrations in the membranes. It is seen that dependences of D on OVTMS concentrations are identical for the various hydrocarbons o f differing MW. Up to c = 2 % D values are constant within the measurement accuracy limits. Where c = 4 3 % , corresponding to T , = 6 0 °, the D values are higher. It is seen f r o m Fig. 2 that the plasticizer concentration has only a slight influence o n permeability coefficients for hydrocarbons in PVTMS. This is apparently due to high values of the permeability coefficients in the case of the plasticized PVTMS, the values being higher by several orders c o m p a r e d with those for polymers where plasticization leads to a marked increase in gas permeability values (PVC, P C T F E a m o n g others) [1]. No superposition o f the spectra of paramagnetic radicals with various rotation
2700
V.V. BARANCmSYS'VAet al.
frequencies is seen for any of the samples of plasticized PVTMS containing spin probes on analyzing the ESR spectra. This is one further fact substantiating the thermodynamic compatibility of PVTMS and OVTMS. The data in Table 2 show the influence of the plasticizer concentration on the spin probe rotation frequency. It can be seen that for small molecules in the plasticized polymers there are identical dependences for the translational D and the rotational mobilities: the v values are constant where c= 0-25 ~o; on further increasing the plasticizer concentration there is increased mobility. It should be noted that molecular volumes for probes I and II differ very significantly, and accordingly there is a difference amounting to one order in their rotation frequencies. However the onset of variation in the rotation frequency appears at one and the same plasticizer concentration (or at the same value of T=) irrespective of the size of the probe.
Tzgo °I
P/ Po
xl o2 *3 zx4
X
8
x O A
×
I
zo FIG. 1
4o c, wt%
o
20
I
40 c, wt.%
FxG.2
FIo. 1. Dependence of the glass-transition temperature Tg on the plasticizer concentration c in the PVTMS-OVTMS system. Fio. 2. Influenceof the OVTMS concentration on the permeability coefficientsfor methane (1), acetylene (2), ethane (3) and allene (4) through membranes based on the plasticized PVTMS, according to data in [7]. To investigate whether a role could be played by plasticizer-induced crystallization [4] X radiograms were obtained for the plasticized PVTMS and (for comparison) for PVTMS without OVTMS. An analysis of the X-ray data shows that all the studied samples are structurally amorphous. Thus it appears that addition of the plasticizer to PVTMS is unaccompanied by any crystallization. It is known from the results of earlier studies [7, 8] that translational diffusion coeti~cients and spin probe rotation frequencies for polymers withdifferent glass-transition temperatures vary in similar ways with variations in T= and there is agreement between the actual D and v values. It is clear from the results of the present work that the same is no less true for the plasticized polymers and the correlations between D and v hold with greater accuracy than for polymers of other types. This substantiates an earlier conclusion that spin probes and gas molecules yield data on identical dynamic and structural peculiarities of polymers. It is known that attempts have been made to relate the mobility of low molecular weight particles in glasslike polymers (particularly those with high glass-transition
Translational and rotational mobility of low molecular weight substances TABLE 1. DIFFUSION COEFFICIENTS FOR THE e t . A s ~ z ~
2701
PVTMS
D x 10 7 ( c m 2 . s e e - 1 ) , at O V T M S concentrations (~,) Gases
0 0. 78 0.13 0.18
Acetylene
Ethane Allene
5.4 0. 79 0.14 0.19
20.8 0. 80 0.12 -
25-1 0. 84 0.15 0-22
43-0 1"35 0"38 0-37
TABLE2. ROTATIONFREQUENCIESFOR SPIN PROBESIN THE PLASTICIZEDPVTMS Probes I
II
0 7.5 0.91
v x 108 (see-1) at OVTMS concentrations (~0) 5-4 I 20.8 25.1 7.2 8.2 7.6 0.91 0.77 0-77
43.0 10.4 1.05
temperatures) to the absence of thermodynamic equilibrium states in glasslike polymers. To support this viewpoint reference has been made to free volume theory, i.e. considerations pertaining to the latter were transferred to the glasslike state [10]. On the other hand some authors have endeavoured to relate mobility in glasslike polymers to smallscale movements [11-14] detectable by N M R methods [6]. The introduction of a plasticizer and a change in the glass-transition of a glasslike polymer will invariably be reflected in its nonequilibrium state (at some given temperature) becoming less marked. As regards small-scale movements, the introduction of a plasticizer may n o t only facilitate, but also impede the latter (the antiplasticization effect), a view that is substantiated by the N M R data obtained with a sample rotating at the magic angle [4, 15]. Data obtained by studying the influence of plasticizer concentration on the diffusion of low molecular weight substances in polymer could well shed light on the role played by both these factors. The influence ofthe plasticizer concentration may be examined for three independent quantities, firstly for coefficients of diffusion of gases and vapours D in plasticized polymer (as reported for the system cellulose nitrate-low molecular weight polyethyleneglycol [3], for PVC-tricresylphosphate [4] and for PVTMS plasticized with dioctyl sebacate and OVTMS (as in [2] and in the present investigation)); secondly, we have the spin probe rotation frequencies v (PVTMS, plasticized with OVTMS (as in the present work)), and thirdly, we have the 1/7"1 relaxation rates (in PVC, based on t h e data obtained by 13C N M R [4]). It was found by innvestigation of all these quantities that the influence of the plasticizer concentration is identical in all the studied systems: in the casse of small concentrations there is a slight reduction, or no change, in the measured value up to a definite plasticizer concentration, after which an increase in the value is observed. While initial reductions in D and in 1/T could be attributed either to a diminution of the nonequilibrium free volume fraction or to the antiplasticization effect, the increase in D, v and 1/7;'1 is attributable solely to an intensification of the small-scale molecular mobility of groups in the polymer on condition that there is still a minimum appearing in the
2702
V. V. BARANCHEYBVAet al.
glasslike region. Otherwise it would have been possible to say that the increase in these values could have been due to the development o f segmental mobility in the polymer. It appears from Fig. 1 and f r o m Tables 1 and 2 that the onset o f rises in D and v in the plasticized PVTMS occurs in the region of the glasslike state for a sample whose glass-transition temperature is higher (by ~ 40 °) than that at which measurements were carried out. F r o m a qualitative standpoint one m a y draw the same conclusion for plasticized PVC for which rises in D and in 1/I"1 were reported for a ~ 15% plasticizer concentration [4]. Thus it appears f r o m a study of the results reported in papers [2-4] and from those obtained in the present work show that at first sight there would seem to be c o m m o n factors underlying changes observed in quantities such as D, v and 1/I"1 for different plasticized polymers. In addition, the results o f a study o f the character o f the mobility o f low molecular weight particles in glassy polymers would indicate that these findings cannot be attributed solely to the nonequilibrium state o f the latter without at the same time taking account of the role that could be played by small-scale motions occurring in these polymers. The authors thank S. A r t a m o n o v for kindly carrying out the X ray analysis o f the plasticized polymers.
Translated by R. J. A. HENDRY REFERENCES
1. D. W. BRUBAKER and K. KAMMERMEYER, Industr. and Engng. Chem. 44: 1465, 1952 2. D. W. BRUBAKER and K. KAMMERMEYER, Industr. and Engng. Chem. 45: 1148, 1953 3. S. A. REITLINGER, Pronitsayemost' polimernylda materialov (Permeability of Polymeric Materials), p. 173, Khimiya, Moscow, 1974 4. A. L. YEVSEYENKO, V. V. TEPLYAKOV, S. G. DURGAR'YAN and N. S. NAMETKIN, Vysokomol. soyed. B21: 153, 1979 (Not translated in Polymer Sci. U.S.S.R.) 5. M. KAWAKAMI, H. IWANAGA, Y. HARA, M. IWAMOTO and S. KAGAWA, J. Appl. Polymer Sci. 27: 2387. 1982 6. M. D. SEFCIK, J. SCHAEFFER, F. L. MAY, D. RANCHER and S. M. DUB, J. Polymer Sci., Polymer Phys. Ed. 21: 1041, 1983 7. ye. p. YAMPOL'SKII, E. G. NOVITSKII and S. G. DURGAR'YAN, Zavod. lab. 46: 256, 1980 8. L. I. ANTSIFEROVA, A. M. VASSERMAN, A. N. IVANOVA, V. A. LIVSHITS and N. S. NADEMETS, Atlas spektrov EPR spinovykh metok i zondov (Atlas of ESR Spectra for Spin Labels and Probes). p. 159, Nauka, Moscow, 1977 9. Yu. P. YAMPOL'SKII, S. G. DURGAR'YAN and N. S. NAMETKIN, Dokl. AN SSSR 261: 708, 1981 10. Yu. P. YAMPOL'SKII, S. G. DURGAR'YAN and N. S. NAMETKIN, Vysokomol. soyed. A24: 536, 1982 (Translated in Polymer Sci. U.S.S.R. 24: 3, 592, 1982) 11. D. R. PAUL, Ber. Bunsenges. phys. Chem. 83: 294, 1979 12. A. Ye. CHALYKH, S. A. NENAKHOV, V. A. SALMANOV, S. S. MIKHAILOVA, S. N. TOLSTAYA and A. N. KHODAN, Vysokomol. soyed. A19: 1488, 1977 (Translated in Polymer Sci. U.S.S.R. 19: 7, 1706, 1977) 13. R. G. PACE and A. DATYNER, J. Polymer Sci. Polymer Phys. Ed. 17: 437, 1979 14. R. G. PACE and A. DATYNER, J. Polymer Sci. Polymer Phys. Ed. 17: 453, 1979
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Films of PC-PAASO block copolymer blends
15. R.G. PACE and A. DATYNER, J. Polymer Sci. Polymer Phys. Ed. 17: 465, 1979 16. R. G. PACE and A. DATYNER, Polymer Engng. Sci. 20: 52, 1980 17. J. SCHAEFER, M. D. SEFCIK, E. O. STEFKAL, R. A. MeKAY, W. T. DIXON and R. E. CAIS, Macromolecules 17: 6, 112, 1984
0032-3950/86$10.00+.00 ~) 1987PergamonJournalsLtd.
Polymer Science U.S.S.R. Vol. 28, No. 11, pp. 2703-2709,1986 Printedin Poland
SELF-BLUNTING OF N O T C H E S IN F I L M S OF POLYCARBONAIY_,-POLYARYLATEARYLENE S U L P H O N O X I D E BLOCK C O P O L Y M E R B L E N D S * V. N. SHOGENOV,G. V. KOZLOV, M. A. GAZAYEVand A. K. MIKITAYEV High Polymer Institute attached to the Cabardino Balkar State University
(Received 16 April 1985) Films of polycarbonate-polyarylatearylenesulphonoxide block copolymer blends underwent stretching, the samples each having a sharp notch. Stretching of the samples with a definite make-up of the blends showed that the rupture stress increases with the increase in the notch length. This was explained with the aid of a model of crack self-blunting by plastic deformation. The degree of self-dulling increases with the growth in the forced elasticity stress.
Is SOLIDpolymers, particularly in film subjected to stretching under conditions where the latter are in horizontally stressed states a major role is played by processes of plastic (or forced-elastic) deformation [1]. Factors influencing the amount of energy required for propagation of a failure-causing crack (particularly in the case of notched samples) may include the volume of the plastically deformed material, the notch parameters, and some others. This paper relates to our study of plastic deformation mechanisms leading to self-blunting of notches (stationary cracks) in film samples containing the polyarylatearylene sulphonoxide block copolymer (PAASO) [2] and blends of varying composition based on PAASO with a polycarbonate (PC) based on bisphenol A. PAASO is a polycondensation type polyblock copolymer, the chemicat structure being of type {[A]~- [B]m- [C]k}x, where
/
0
/ 0
II
/II
CHa
,~
I
A = [ - - C - - , / f l - ' ~ .C - - O - - / ' J - - ~ ' - - C - - / ~ - - ' \ \ - - 0 - - ~ CHa * Vysokomol. soyed. A28: No. 11, 2430-2435, 1986.
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