Synthesis and characterization of new ABA triblock copolymers with poly[3(S)-isobutylmorpholine-2,5-dione] and poly(ethylene oxide) blocks

✍ Scribed by Yakai Feng; Doris Klee; Hartwig Höcker

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 114 KB
• Volume: 200
• Category: Article
• ISSN: 1022-1352
• DOI: 10.1002/(sici)1521-3935(19991001)200:10<2276::aid-macp2276>3.0.co;2-n

✦ Synopsis

ABA type block copolymers with poly[3(S)-isobutylmorpholine-2,5-dione] (PIBMD, A) and poly(ethylene oxide) (M n = 6 000, PEO, B) blocks, PIBMD-b-PEO-b-PIBMD, were synthesized via ringopening polymerization of 3(S)-isobutylmorpholine-2,5-dione in the presence of hydroxytelechelic poly-(ethylene oxide) with stannous octoate as a catalyst. M n of the resulting copolymers increases with increasing 3(S)-isobutylmorpholine-2,5-dione content in the feed at constant mole ratio of monomer (M) to catalyst (C) (M/C = 125). No racemization of the leucine residue takes place during both homopolymerization of IBMD and polymerization of IBMD in the presence of PEO and Sn(Oct) 2 . The melting temperature of the PIBMD segments in the block copolymers depends on the length of the PIBMD blocks. The melting temperature of the PEO blocks is lower than that of the homopolymer, and the crystallinity of the PEO block decreases with increasing length of the PIBMD blocks. The PIBMD block crystallizes first upon cooling from the melt. This leads to only imperfect crystallization or no crystallization of the PEO blocks.