Slightly Cross-Linked Polyrotaxanes Made by Linking Α-Cyclodextrins Entrapped in Polyrotaxanes Using Hexamethylene Diisocyanate
Ji, Guozhen and Ma, Shenming
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 Pluronic 17R4 with a varying amount of α-cyclodextrins (α-CDs) in the presence of CuCl/PMDETA at 25°C in aqueous solution. the α-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°C. the structures of the PR-based triblock copolymers and SCPRs were characterized by ¹H NMR, ¹³C CP/MAS, GPC and TGA analyses. 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.
S. Li et al., "Slightly Cross-Linked Polyrotaxanes Made by Linking Α-Cyclodextrins Entrapped in Polyrotaxanes Using Hexamethylene Diisocyanate," Chinese Journal of Chemistry, Wiley-VCH Verlag, Jan 2012.
The definitive version is available at http://dx.doi.org/10.1002/cjoc.201200280
Mechanical and Aerospace Engineering
Keywords and Phrases
Î±-Cyclodextrin; Polyrotaxane; ATRP; Poly(N-Isopropylacrylamide); Hexamethylene Diisocyanate
Article - Journal
© 2012 Wiley-VCH Verlag, All rights reserved.