Journal of Polymer Science Part A: Polymer Chemistry, Vol.44, No.11, 3684-3691, 2006
Preparation of novel poly(ethyleneoxide-co-glycidol)-graft-poly(epsilon-caprolactone) copolymers and inclusion complexation of the grafted chains with alpha-cyclodextrin
A well-defined comblike copolymer of poly(ethylene oxide-co-glycidol) [(poly (EO-co-Gly)] as the main chain and poly(epsilon-caprolactone) (PCL) as the side chain was successfully prepared by the combination of anionic polymerization and ring-opening polymerization. The glycidol was protected by ethyl vinyl ether to form 2,3-epoxypropyl-1-ethoxyethyl ether (EPEE) first, and then ethylene oxide was copolymerized with EPEE by an anionic mechanism. The EPEE segments of the copolymer were deprotected. by formic acid, and the glycidol segments of the copolymers were recovered after saponification. Poly(EO-co-Gly) with multihydroxyls was used further to initiate the ring-opening polymerization of epsilon-caprolactone in the presence of stannous octoate. When the grafted copolymer was mixed with alpha-cyclodextrin, crystalline inclusion complexes (ICs) were formed, and the intermediate and final products, poly(ethylene oxide-co-glycidol)-graft-poly(epsilon-caprolactone) and ICs, were characterized with gel permeation chromatography, NMR, differential scanning calorimetry, X-ray diffraction, and thermogravimetric analysis in detail. The obtained ICs had a channel-type crystalline structure, and the ratio of alpha-caprolactone units to a-cyclodextrin for the ICs was higher than 1:1. (c) 2006 Wiley Periodicals, Inc.