Slightly Cross-Linked Polyrotaxanes Made by Linking α-Cyclodextrins Entrapped in Polyrotaxanes Using Hexamethylene Diisocyanate

• Published in: Chinese journal of chemistry Vol. 30; no. 10; pp. 2453 - 2460
• Main Author: 李硕 王锦 姜岚 叶霖 张爱英 冯增国
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.10.2012; WILEY‐VCH Verlag
• Subjects: ATRP; hexamethylene diisocyanate; N-异丙基丙烯酰胺; poly(N-isopropylacrylamide); polyrotaxane; α-cyclodextrin; 三嵌段共聚物; 交联; 六亚甲基二异氰酸酯; 原子转移自由基聚合; 环糊精; 轮烷; 链接
• ISSN: 1001-604X; 1614-7065
• DOI: 10.1002/cjoc.201200280

In this study polyrotaxane （PR）-based triblock copolymers were first synthesized via the atom transfer radical polymerization （ATRP） of N-isopropylacrylamide initiated with the self-assembly of a distal 2-bromoisobutyryl end-capped Pluronie 17R4 with a varying amount of a-cyclodextrins （a-CDs） in the presence of CuCI/PMDETA at 25 ℃ in aqueous solution. The a-CDs entrapped on the copolymer chain were then linked with hexamethylene diisocyanate to give rise to novel slightly cross-linked polyrotaxanes （SCPRs） in DMF at 45 ℃. The structures of the PR-based triblock copolymers and SCPRs were characterized by 1H NMR, 13C CP/MAS, GPC and TGA analy- ses. The number-average molecular weight of the resulting SCPRs was nearly three and five times of their precursor after linking with a low polydispersity index range of 1.08--1.28. The thermo-responsive transition of both PR-based supramolecular polymers in aqueous solution was demonstrated by turbidity measurements and the self-aggregated morphologies were also evidenced by TEM observations.