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Date of Publication:2007-01-01

Journal:功能材料

Issue:3

Page Number:423-426

ISSN No.:1001-9731

Abstract:Hydroxyl-terminated poly (L-lactic acid) (PLLA) was prepared by melt condensation process with ethylene glycol. Lactic acid-based polyurethanes (PU) modified by rubber were prepared via the coupling reaction between hydroxyl-terminated poly (L-lactic acid) (PLLA) and polybutadiene (HTPB) prepolymers with methylene diphenyldiisocyanate (MDI) terminals. The chemical structures of the resulting product were confirmed with FT-IR, 1H, 13C NMR, and GPC. DSC spectra indicated that the Tm of the resulting polymers was close to the prepolymer PLLA. The copolymers had two Tg, that is, the Tg1 of the polybutadiene soft segment and the Tg2 of the PLLA hard segment, suggesting unmiscibility and phase separation between the soft and hard segments. With increasing PB content in the chain of the polyurethanes, the diffraction peaks of the polyurethanes disappeared slightly observed by XRD and the tensile strength of the samples decreased and the strain of the samples increased. The SEM analysis of ruptured surface of the polyurethanes showed the morphology is similar to the micro-phase separation structure and attributed elastic rupture.

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