摘要
本文用傅里叶变换红外光谱(FTIR)研究了从高弹态缓冷、高弹态淬火以及其后在低于T_g温度热处理的三种不同热历史聚氯乙烯膜的结构差异。在升温在位FTIR测量中,发现经低于T_g温度热处理的样品在与示差扫描量热(DSC)热焓吸收牛相对应的温度区间有构象突变发生,并用高分子链缠结的观点加以解释。
Three specimens from solution cast polyvinyl chloride (PVC) films, one being ice-water quenched from 120℃(Q), one being slowly cooled from 120℃ (SC) and one being quenched and sub-Tg, annealed at 72℃ for 48h (AN), have been studied by infrared difference spectra Q-SC and AN-Q and temperature difference spectra of T2-T1 for every 4℃ step on heating to 120℃ at 2℃/min. SC and AN showed more trans conformers than Q. It means that the PVC chain has more gauche conformers at higher temperatures and some of these are frozen during quenching through Tg. The temperature difference spectra on heating through Tg showed that the conformation changes in Q are gradual while a rather abrupt change occurs in AN at 92-88℃. A kind of chain entanglement mechanism is suggested which hinders the molecular conformation changes in AN below Tg until a sudden release occurs at Tg.
出处
《高分子学报》
SCIE
CAS
CSCD
北大核心
1991年第6期667-671,共5页
Acta Polymerica Sinica
基金
国家自然科学基金会
中国科学院资助的重大项目
关键词
聚氯乙烯
薄膜
红外光谱
玻璃化
FTIR, Glass transition, Polyvinyl chloride, Conformation, Chain entanglement.
