Phase segregation of polyester based-polyurethanes

Polyester based polyurethanes were synthesized from 4,4'-methylene bis(phenyl isocyanate) (MDI) with 1.4-butanediol as a chain extender and low molecular weight polyester-diol as a soft segment. Four polyesters were used in the synthesis of polyurethanes. Two of the polyesters were synthesized from monomers with even carbon atoms, i.e., adipic acid with 1,6-hexanediol (polyester-6-6) and adipic acid with 1,4-butanediol (polyester-6-4). The other two polyesters were synthesized from monomers with odd carbon atoms, i.e., pimelic acid with 1,5-pentanediol (polyester-7-5) and 1,5-pentanedioic acid with 1,5-pentanediol (polyester-5-5). The effects of compatibility between soft- and hard-segments and the chemical structures of polyesters on the phase segregation of soft- and hard-segments were studied by DSC and FT-IR.