Isothermal Crystallization Behavior of Polypropylene/Polyolefin Elastomer with β -Nucleating Agent

The effect of β-nucleating agent (β-NA) and polyolefin elastomer (POE) on the crystal structure and isothermal crystallization of polypropylene (PP) was studied by using polarized optical microscopy (POM), scanning electron microscope (SEM), differential scanning calorimetry (DSC), and rheological measurements. The results indicated that the self-assembled needlelike β-NA significantly promoted the crystallization process of the PP matrix, which accelerated the crystalline transformation from α-crystal to β-crystal in DSC cyclic scans. Owing to the POE improved the dispersion of β-NA in polymer matrix, the half crystallization time and activation energy of the PP/POE/β-NA blend were the lowest among all PP specimens. Furthermore, the values of Avrami exponent were less than 2 for PP/β-NA and PP/POE/β-NA blends, which is much lower than that of pure PP.