Poly(dimethylsiloxane)-Polyurethane Elastomers: Synthesis and Properties of Segmented Copolymers and Related Zwitterionomers.
WISCONSIN UNIV-MADISON DEPT OF CHEMICAL ENGINEERING
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A series of polyurethane block polymers based on hydroxybutyl-terminated polydimethylsiloxane soft segments of molecular weight 2000 were synthesized. The hard segments consisted of 4,4-methylenediphenylene diisocyanate MDI which was chain extended with either 1,4-butanediol BD or N-methyldiethanolamine MDEA. The MDEA-extended materials were ionized using 1,3-propane sultone. The weight fraction of hard segments was in range 0.13-o.39. The morphology and properties of these polyurethane elastomers were studied by variety of techniques. All of these short segment block copolymers showed nearly complete phase separation. The zwitterionomer materials exhibited ionic aggregation with the hard domains. Hard segment crystallinity or ionic aggregation did not affect the morphology. Hard domain cohesion was found to be a more important factor than hard domain volume fraction in determining the tensile and viscoelastic properties of these elastomers. Author
- Elastomers and Rubber