PHASE-TRANSITIONS IN NARROW-MOLAR-MASS SAMPLES OF SIDE-CHAIN LIQUID-CRYSTALLINE POLYMERS - MOLAR-MASS DEPENDENCE

被引：12

作者：

GEDDE, UW ^{[1
]}

JONSSON, H ^{[1
]}

HULT, A ^{[1
]}

PERCEC, V ^{[1
]}

机构：

[1] CASE WESTERN RESERVE UNIV,DEPT MACROMOLEC SCI,CLEVELAND,OH 44106

来源：

POLYMER | 1992年 / 33卷 / 20期

关键词：

SIDE-CHAIN SMECTIC POLYMERS; NARROW MOLAR MASS; PHASE TRANSITIONS; MOLAR-MASS DEPENDENCE; POLY(VINYL ETHER)S);

D O I：

10.1016/0032-3861(92)90279-6

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 molar-mass dependence of phase transitions in narrow-molar-mass samples of smectic side-chain poly(vinyl ether)s is discussed with reference to earlier data by Stevens et al. and Percec et al. on narrow fractions of smectic side-chain polysiloxanes and polymethacrylates. The constant heat of isotropization (DELTAh(i)) and the proportionality between the glass transition temperature (T(g)) and the reciprocal degree of polymerization (DP) observed for polysiloxanes and polymethacrylates indicate that the order within the smectic layers and the penetration of the flexible main chains of the smectic layers was not appreciably affected by changes in DP. The poly(vinyl ether)s on the other hand exhibited a pronounced decrease in DELTAh(i) with increasing DP and a more complex correlation between T(g) and DP indicative of an increasing disturbance by the flexible main chains of the smectic layers with increasing DP. These differences between polysiloxanes/polymethacrylates and poly(vinyl ether)s were also found to have profound effects on the DP dependence of the isotropization temperature.

引用

页码：4352 / 4357

页数：6