Release Time:2019-03-13  Hits:

Indexed by: Journal Article

Date of Publication: 2007-04-01

Journal: EUROPEAN POLYMER JOURNAL

Included Journals: EI、SCIE

Volume: 43

Issue: 4

Page Number: 1210-1218

ISSN: 0014-3057

Key Words: beta-butyrolactone; poly-3-hydroxybutyrate; dibutylmagnesium; kinetics; mechanism

Abstract: Ring opening polymerization (ROP) of (R,S)-beta-butyrolactone (BL) using dibutylmagnesium (Bu2Mg) as initiator was investigated both in bulk and in solution. The synthetic poly-3-hydroxybutyrates (P3HB) were characterized by H-1 NMR, C-13 NMR, FT-IR and GPC. Effects of molar ratio of initiator to monomer, reaction temperature and time on the monomer conversion and the polymer molecular weight and its distribution were discussed. The kinetics of the solution polymerization of BL was examined and showed a first order both in monomer concentration and initiator concentration. The end groups analysis suggested that the monomer inserted into the growing chain proceeding through the coordination-insertion mechanism based on the acyl-oxygen bond scission rather than the alkyl-oxygen bond cleavage of the BL ring. Furthermore, a possible mechanism for the initiation and propagation procedures of P3HB synthesized from BL with Bu2Mg was proposed. (C) 2007 Elsevier Ltd. All rights reserved.