PMMA—b—PTHF／PTHF共混体系中共聚物结晶能力的增强

结晶嵌段共聚物具有一般均聚物所没有的许多特殊结晶行为。虽然,人们很早就已开始对聚氧化乙烯/聚苯乙烯诸类嵌段共聚物的结晶行为进行研究,但对这类体系相分离规律及结晶行为的认识仍很不够。这主要是因为已研究的体系非常有限,此外,大都为对体系非平衡态结构的研究。所以,尽管Whitmore和Noolandi最近提出了结晶嵌段共聚物及其共混物的平衡形态理论,但缺乏实验数据与之比较。

CRYSTALLIZATION OF BLOCK COPOLYMER IN POLY (METHYL METHACRYLATE-b-TETRAHYDROFURAN)/POLYTETRAHYDROFURAN BLENDS

The crystallization behavior of poly (methyl methacrylate-b-tetrahydrofuran) diblockcopolymer (PMMA-b-PTHF) and its blends with PTHF homopolymer has been studiedusing DSC technique. Because the crystallization of the PTHF block of the copolymer isstrongly hampered by the amorphous PMMA block of the copolymer. only a very small peakat very low temperature is observed in its DSC thermogram obtained during cooling, indi-cating a very low nucleation rate and a very low crystallinity. However, it was found thatthe copolymer in PMMA-b-PTHF/PTHF blends crystallizes at a much higher temperatureduring meling and a much higher crystallinity was detected. It may resulte mainly fromthe favorable conformation of the crystallizable block in blends.