writer：G Wu, SC Chen, Q Zhan, YZ Wang
keywords：amphiphiles，graft copolymers，micelles，micellization，poly(p-dioxanone)，poly(vinyl alcohol)，ring-opening polymerization
source：期刊
specific source：Journal of Polymer Science Part A: Polymer Chemistry
Issue time：2010年
A series of amphiphilic biodegradable and biocompatible poly(p-dioxanone)-grafted poly(vinyl alcohol) (PVA) copolymers with well-defined structure were obtained by a three-step synthesis based on the "grafting from" concept. The first step (protection step), called the partial silylation of PVA hydroxyl groups, was accomplished by 1,1,1,3,3,3-hexamethyl-disilazane and catalyst chlorotrimethylsilane in dimethyl sulfoxide using THF as cosolvent. The second step was the ring-opening polymerization of p-dioxanone (PDO) initiated from the remaining OH groups of the partially silylated PVA. Finally, a deprotection step was followed: the silylether group was deprotected easily under very mild conditions. The synthetic conditions of the first two steps were investigated, and the structures of polymers formed in each step were characterized by various analytical methods. The results showed that the molecular structure of the PVA-g-PPDO could be controlled easily by the degree of silylation and the feed ratio. In addition, the micellization of amphiphilic PVA-g-PPDO copolymers in water was proved by fluorescence spectra and dynamic light scattering, and the relationship between structural parameters of copolymers and micellar properties was studied preliminarily.