THE LOW-TEMPERATURE RELAXATION MECHANISMS IN POLY(VINYL ACETATE) - A THERMALLY STIMULATED CURRENTS STUDY

被引:25
作者
DIAS, AB
RAMOS, JJM
WILLIAMS, G
机构
[1] IST,CTR QUIM FIS MOLEC,COMPLEXO 1,AV ROVISCO PAIS,P-1096 LISBON,PORTUGAL
[2] UNIV COLL SWANSEA,DEPT CHEM,SWANSEA SA2 8PP,W GLAM,WALES
关键词
THERMALLY STIMULATED CURRENT; POLY(VINYL ACETATE); DIPOLAR RELAXATION;
D O I
10.1016/0032-3861(94)90020-5
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
The dipolar relaxation behaviour of poly(vinyl acetate) has been studied extensively in the low temperature region from -160 to -20-degrees-C. It is shown that the observed relaxation peak does not correspond to a single relaxation process but to a continuous distribution of relaxation times. The components of this distribution show Arrhenius behaviour and the corresponding activation energies are low (approximately 8 kcal mol-1). which suggests that the dipolar motions involved are local motions, probably internal rotations about single bonds in the acetate groups. A continuous increase of the Gibbs activation energy for higher temperature components is observed, which is a consequence of a lowering of the activation entropy (the higher temperature relaxation modes have more negative activation entropies).
引用
收藏
页码:1253 / 1257
页数:5
相关论文
共 11 条
[1]   THERMALLY STIMULATED CURRENT AND CREEP IN AMORPHOUS POLY(ETHYLENE-TEREPHTHALATE [J].
BERTICAT, P ;
LACABANNE, C ;
MONPAGENS, JC ;
CHATAIN, D .
JOURNAL OF MACROMOLECULAR SCIENCE-PHYSICS, 1978, B15 (04) :549-565
[2]   IONIC THERMOCURRENTS IN DIELECTRICS [J].
BUCCI, C ;
FIESCHI, R ;
GUIDI, G .
PHYSICAL REVIEW, 1966, 148 (02) :816-&
[3]  
CARR SH, 1982, ELECTRICAL PROPERTIE
[4]   INFLUENCE OF TACTICITY ON T-BETA, T-G, AND T-LL IN POLY(METHYL METHACRYLATE)S BY THE METHOD OF THERMALLY STIMULATED CURRENT (TSC) [J].
GOURARI, A ;
BENDAOUD, M ;
LACABANNE, C ;
BOYER, RF .
JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS, 1985, 23 (05) :889-916
[5]  
IBAR JP, 1990, ADV CHEM SERIES, V227
[6]   DIELECTRIC-RELAXATION OF POLYVINYL ACETATE) [J].
MASHIMO, S ;
NOZAKI, R ;
YAGIHARA, S ;
TAKEISHI, S .
JOURNAL OF CHEMICAL PHYSICS, 1982, 77 (12) :6259-6262
[7]  
McCrum NG., 1991, ANELASTIC DIELECTRIC
[8]   DIELECTRIC-RELAXATION MEASUREMENTS OF POLYVINYL ACETATE) IN GLASSY STATE IN THE FREQUENCY-RANGE 10-6-106 HZ [J].
NOZAKI, R ;
MASHIMO, S .
JOURNAL OF CHEMICAL PHYSICS, 1987, 87 (04) :2271-2277
[9]  
ORVILLETHOMAS WJ, 1974, INTERNAL ROTATION MO
[10]   GENERAL PROPERTIES OF SECONDARY RELAXATIONS IN POLYMERS AS DETERMINED BY THERMALLY STIMULATED CURRENT METHOD [J].
VANDERSCHUEREN, J .
JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS, 1977, 15 (05) :873-880