LOCAL CHAIN DYNAMICS OF BULK AMORPHOUS POLYBUTADIENES - A MOLECULAR-DYNAMICS STUDY

被引:64
作者
KIM, EG [1 ]
MATTICE, WL [1 ]
机构
[1] UNIV AKRON,MAURICE MORTON INST POLYMER SCI,AKRON,OH 44325
关键词
D O I
10.1063/1.468502
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The local motions of bulk amorphous polybutadienes (PBDs) have been studied by a molecular dynamics simulation. Fully atomistic models of PBDs have been obtained at a realistic bulk density under periodic boundary conditions. Local chain motions are examined for poly(cis-1,4-butadiene) (cis-PBD) and poly(trans-1,4-butadiene) (trans-PBD) well above the glass transition temperature, where the only structural difference is imposed by the different conformational states at the double bond. The local motions are found to be strikingly different in the two polymers. Intramolecular cooperative conformational transitions occur at second-neighbor bond pairs of CH-CH, in both PBDs. In trans-PBD, both CH2-CH2 and CH=CH triplets undergo cooperative counterrotations. In cis-PBD, CH2-CH2 triplets undergo counterrotations while CH=CH triplets undergo corotations. Intermolecular cooperativity, probed by the local free volume, has Little influence on local relaxation processes. The effect of libration on the shape of autocorrelation functions (ACFs) is significant over the entire time range. A universality is found in the time evolution of the Kohlrausch-Williams-Watts exponent regardless of the type and order of the ACF. On the other hand, the single exponential decay regarded as common at short times is only due to the discreteness of conformational states.
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页码:6242 / 6254
页数:13
相关论文
共 68 条
[11]   MOLECULAR-DYNAMICS WITH COUPLING TO AN EXTERNAL BATH [J].
BERENDSEN, HJC ;
POSTMA, JPM ;
VANGUNSTEREN, WF ;
DINOLA, A ;
HAAK, JR .
JOURNAL OF CHEMICAL PHYSICS, 1984, 81 (08) :3684-3690
[12]   MOLECULAR-DYNAMICS IN BULK CIS-POLYISOPRENE AS STUDIED BY DIELECTRIC-SPECTROSCOPY [J].
BOESE, D ;
KREMER, F .
MACROMOLECULES, 1990, 23 (03) :829-835
[13]   TIME-CORRELATION FUNCTIONS FOR A ONE-DIMENSIONAL POLYMER MODEL [J].
COOK, R ;
HELFAND, E .
JOURNAL OF CHEMICAL PHYSICS, 1985, 82 (03) :1599-1605
[14]  
DEJEANDELABATIE R, 1988, MACROMOLECULES, V21, P2052
[15]  
DEJEANDELABATIE R, 1988, MACROMOLECULES, V21, P2045
[16]  
DEJEANDELABATIE R, 1989, MACROMOLECULES, V22, P122
[17]   SIMULATION BY MOLECULAR-DYNAMICS OF POLY(1,4-TRANS-BUTADIENE) AS AN INCLUSION COMPLEX IN THE CHANNEL OF CRYSTALLINE PERHYDROTRIPHENYLENE [J].
DODGE, R ;
MATTICE, WL .
MACROMOLECULES, 1991, 24 (10) :2709-2714
[18]  
EDIGER MD, 1991, ANNU REV PHYS CHEM, V42, P255
[19]   LOCAL DYNAMICS OF POLYISOPRENE IN TOLUENE [J].
GISSER, DJ ;
GLOWINKOWSKI, S ;
EDIGER, MD .
MACROMOLECULES, 1991, 24 (15) :4270-4277
[20]   DIELECTRIC RELAXATION OF ISOAMYL BROMIDE [J].
GLARUM, SH .
JOURNAL OF CHEMICAL PHYSICS, 1960, 33 (03) :639-643