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Synthesis and characterization of new ABA triblock copolymers with poly[3( S )‐isobutylmorpholine‐2,5‐dione] and poly(ethylene oxide) blocks
Author(s) -
Feng Yakai,
Klee Doris,
Höcker Hartwig
Publication year - 1999
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/(sici)1521-3935(19991001)200:10<2276::aid-macp2276>3.0.co;2-n
Subject(s) - copolymer , ethylene oxide , polymer chemistry , crystallinity , polymerization , materials science , monomer , crystallization , oxide , chemistry , polymer , organic chemistry , composite material , metallurgy
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 ring‐opening 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.