Abstract:
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A set of linear polyurethanes containing
isosorbide units were synthesized by polymerization in solution from HDI and MDI diisocyanates and 1,4-butanediol(BD), isosorbide (Is) or diisosorbide diurethanes
(Is2HDI and Is2MDI) as diols. The thermal transitions, thermal stability, and crystal structure of the polyurethane homopolymers and copolymers containing isosorbide were evaluated and compared with those displayed
by their polyurethane analogues entirely made of BD. It was found that incorporation of Is units in the polyurethane chain produced significant changes in Tg, Tm,
and Td but no significant differences were noticed between copolymers made from Is or Is2 monomers. Degradation assays revealed that the presence of Is units increased slightly the hydrolysis rate of polyurethanes. |