INTERNAL MOTIONS IN POLYLACTIDE AND RELATED POLYMERS

被引：32

作者：

STARKWEATHER, HW ^{[1
]}

AVAKIAN, P ^{[1
]}

FONTANELLA, JJ ^{[1
]}

WINTERSGILL, MC ^{[1
]}

机构：

[1] USN ACAD,DEPT PHYS,ANNAPOLIS,MD 21402

来源：

MACROMOLECULES | 1993年 / 26卷 / 19期

关键词：

D O I：

10.1021/ma00071a016

中图分类号：

O63 [高分子化学（高聚物）];

学科分类号：

070305 ; 080501 ; 081704 ;

摘要：

Polylactide(approximately 95% L-isomer), polyglycolide, and a 1:1 copolymer were studied by differential scanning calorimetry, dynamic mechanical analysis, and dielectric relaxation. In addition to the previously known glass transitions, all of these polymers exhibit a relaxation similar to the beta-relaxation which occurs in many other materials. This relaxation, which occurs near 200 K at 1 kHz, is attributed to noncooperative local motions. Another new relaxation near 15 K was found in polyactide and the copolymer but not polyglycolide and hence is attributed to motions of the methyl side groups. The effect of increased humidity on polylactide was also investigated. The weight gain of the samples depends strongly on the relative humidity and continues over extended periods of time. Changes in the dielectric relaxation spectra were consistent with substantial decreases in molecular weight.

引用

页码：5084 / 5087

页数：4

共 18 条

[1] THERMAL-PROPERTIES AND PHYSICAL AGING OF POLY(L-LACTIC ACID) [J].