Synthesis and characterization of poly[(R,S)-3-hydroxybutyrate] telechelics and their use in the synthesis of poly(methyl methacrylate)-b-poly(3-hydroxybutyrate) block copolymers

Poly[(R,S)-3-hydroxybutyrate] oligomers containing dihyroxyl (PHB-diol), dicarboxylic acid (PHB-diacid) and hydroxyl-carboxylic acid (a-PHB) end functionalities were obtained by the anionic polymerization of ß-butyrolacton (ß-BL). Ring opening anionic polymerization of ß-BL was initiated by a complex of 18-Crown-6 with ?-hydroxybutyric acid sodium salts (for PHB-diol and a-PHB) or succinic acid disodium salt (for PHB-diacid). Dihydroxyl functionalization was formed by the termination of polymerization with bromo-ethanol or bromo-decanol while the others were done by protonation. Hydroxyl and/or carboxylic acid functionalized PHB oligomers with ceric salts were used to initiate the polymerization of methylmethacrylate (MMA). PHB-b-PMMA block copolymers obtained by this way were purified by fractional precipitation and characterized using 1H-NMR and 13C-NMR, gel permeation chromatography (GPC), and thermal analysis (DSC and TGA) techniques. © 2002 Wiley Periodicals, Inc. J. Appl. Polym. Sci