LIQUID-CRYSTALLINE POLY(AZOMETHINE)S .2. STRUCTURAL FORMATION KINETICS

被引：16

作者：

CHENG, SZD ^{[1
]}

JANIMAK, JJ ^{[1
]}

LIPINSKI, TM ^{[1
]}

SRIDHAR, K ^{[1
]}

HUANG, XY ^{[1
]}

HARRIS, FW ^{[1
]}

机构：

[1] UNIV AKRON, COLL POLYMER SCI & POLYMER ENGN, DEPT POLYMER SCI, AKRON, OH 44325 USA

来源：

POLYMER | 1990年 / 31卷 / 06期

关键词：

crystal; enthalpy relaxation; glass transition; isotropic; kinetics; liquid crystal; liquid-crystalline glass; nematic; poly(azomethine); structure recovery; sub-T[!sub]g[!/sub] annealing; texture;

D O I：

10.1016/0032-3861(90)90261-V

中图分类号：

O63 [高分子化学（高聚物）];

学科分类号：

070305 ; 080501 ; 081704 ;

摘要：

Characterization of the structural formation kinetics in a series of liquid-crystalline poly(azomethine)s (PAMEs), containing different numbers (n) of ethylene glycol flexible spacers, has been investigated. It has been previously established that, after crystal melting, all PAMEs demonstrate a nematic liquid-crystalline phase, prior to their isotropic melts. The polymers only exhibit liquid-crystalline glassy phases after quenching (n = 1) or on cooling (n = 2, 3 and 4). The isotropic to nematic transitions for PAMEs (n = 2, 3 and 4) proceed by two processes: a fast process followed by a slow structure-sensitive process achieved only on annealing isothermally. Both the fast and the slow processes are greatly influenced by the number of flexible spacers. The fast process is closely associated with a texture of high disclination density, whereas the slow process involves transformations of disclination. Isothermal experiments in the sub-Tg region reveal that the enthalpy relaxations for quenched samples from the nematic and isotropic states are different in the initial stages. The kinetics of this relaxation phenomenon has also been discussed. © 1990.

引用

页码：1122 / 1129

页数：8

共 31 条

[1] STRUCTURAL CHANGES IN GLASSY POLYMERS [J].