Pack, JW Kim, SH Cho, IW Park, SY Kim, YH 2024-01-21T11:06:20Z 2024-01-21T11:06:20Z 2021-09-05 2002-02-15 0887-624X https://pubs.kist.re.kr/handle/201004/139770 Glycolide (GL) and epsilon-caprolactone (CL) were copolymerized in bulk at relatively high temperatures using stannous octoate as a catalyst. To investigate the relationship among microstructure, thermal properties, and crystallinity, three series of copolymers prepared at various reaction temperatures, times, and comonomer feed ratios were prepared and characterized by H-1 and C-13 NMR, DSC, and wide-angle X-ray diffraction (WAXD). The 600-MHz H-1 NMR spectra provided information about not only the copolymer compositions but also about the chain microstructure. The reactivity ratios (r(G) and r(C)) were calculated from the monomer sequences and were 6.84 and 0.13, respectively. In terms of overall feed compositions, the sequence lengths of the glycolyl units calculated from the reactivity ratios exceeded those measured from the polymeric products. Mechanistic considerations based on reactivity ratios, monomer consumption data, and average sequence lengths are discussed. The unusual phase diagram of GL/CL copolymers implies that the copolymer melting temperature does not depend on its composition alone but rather on the nature of the sequence distribution. The DSC and WAXD) measurements show a close relationship between polymer crystallinity and the nature of the polymer sequence. (C) 2002 John Wiley Sons, Inc. English JOHN WILEY & SONS INC L-LACTIDE POLYLACTONES POLYMERIZATION L,L-DILACTIDE DEGRADATION CARBONATE MECHANISM POLYMERS Microstructure analysis and thermal property of copolymers made of glycolide and epsilon-caprolactone by stannous octoate Article 10.1002/pola.10123 1 JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, v.40, no.4, pp.544 - 554 JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY 40 4 544 554 scie scopus 000173391200011 2-s2.0-0037083185 Polymer Science Polymer Science Article L-LACTIDE POLYLACTONES POLYMERIZATION L,L-DILACTIDE DEGRADATION CARBONATE MECHANISM POLYMERS glycolide epsilon-caprolactone reactivity ratio average sequence length comonomer sequence distribution biodegradable copolymerization NAIR