Crystallization and Melting Behaviors of Polylactic Acid/Thermoplastic Polyurethane Blends

A series of blends were prepared by different ratios of polylactic acid (PLA) and thermoplastic polyurethane (TPU) with a crosslinking agent of dicumyl peroxide (DCP). This study focused on the crystal structure, morphology, crystallization, and melting behaviors of PLA/TPU blends using a wide angle x-ray diffractometer (WAXD), a polarizing optical microscope (POM) and a differential scanning calorimeter (DSC). A Modified Avrami equation was applied to analyze non-isothermal crystallization kinetics of PLA/TPU blends. Results show that the nucleation of PLA was enhanced by the added TPU. The spherulitic growth rate, crystallization rate, and crystallinity of the PLA/TPU blends increased with an increase of TPU content. WAXD results show that all of the crystal reflections of PLA/TPU blends related to those of PLA.