Crystallization Behaviors of ammo-terminated polyurethane(ATPU)-grafted polypropylene

摘要

A melt-grafting approach was employed to prepare a novel functional polypro-pylene(FPP)-amino-terminated polyurethane grafted polypropylene(PP-g-ATPU).The crystallization behaviors of PP and PP/FPP blends were characterized using differential scanning calorimetry(DSC),wide angle X-ray scattering(WAXS)and polarized optical microscopy(POM).The effects of FPP composition on crystallization behavior,crystal transformation,and morphology of PP/FPP crystalline were investigated.The results showed that at a low dosage(< 2.0wt%)ATPU acted as a heterogeneous nucleation agent during the crystallization of PP/FPP blends.However,when the content of ATPU reached 2.0wt% or higher,ATPU deteriorated the crystallization of PP or PP/FPP blends.The crystallite size decreased and the number of crystallites increased as the ATPU content increased.The Avrami analysis was adopted to describe the isothermal crystallization process.The difference in the exponent n between PP and PP/FPP suggested that the isothermal crystallization kinetics of PP/FPP blends followed a three-dimensional growth via heterogeneous nucleation.In terms of the half-time of the crystallization,t_(1/2),the crystallization rate of functional PP blends was faster than that of PP homopolymer at a given crystallization temperature.