SYNTHESIS AND PROPERTIES OF THERMOPLASTIC POLYURETHANE ELASTOMERS MODIFIED BY POLY(GAMMA-METHYL-L-GLUTAMATE) SEGMENT

Thermoplastic polyurethane elastomers (TPUs) from diol-terminated poly (tetramethylene glycol) (PTMG), 1,4-butanediol (BD) and 4,4'-diphenylm ethane diisocyanate (MDI) were modified by copolymerizing with diamine -terminated poly(gamma-methyl-L-glutamate) oligomer (gamma-PMG). In TP Us modified by the gamma-PMG segment, the hard segment showed a decrea sed crystallinity and a melting point depression, as some of the hard segments were replaced by the gamma-PMG segment. This behaviour is pro bably due to the strong interaction and phase mixing between gamma-PMG and hard segments. The melting behaviour of the PTMG segment suggeste d a weaker interaction between gamma-PMG and PTMG segments compared wi th that between hard segments and PTMG segments. When a small amount o f hard segments was replaced by gamma-PMG segments, the modulus increa sed and the elongation at break decreased.