The structure and performance study of PP random impact resistance copolymer

Four samples, including homopolymerized PP (PP-1), random impact copolymerized PP (PP-2), random impact copolymerized PP of ethylene-propylene (PP-3), and random impact copolymerized PP of ethylene-propylene-butylene (PP-4), which were prepared by 75 KG Spheripol process pilot plant using ZN104M as catalyst, were adopted to study the structure and performance, i.e. , the influence of the different polypropylene molecular chain structures on the crystallization behavior of random impact copolymer polypropylene, and the changes in mechanical and optical performance due to the different aggregation structures of random impact copolymer polypropylene, and following results were achieved. Firstly, when ethylene-propylene rubber (EPR) and copolymerization monomers of ethylene and butylene were added in turn, the regularity of PP molecular chains decreased in different degree with the order of PP-1 > PP-2 > PP-3 > PP-4, and which further led to the same pattern for the crystallization peak temperature and the crystallinity. Secondly, half-crystallization time ( T 1/2 ) of the same cooling rate and the crystallization activation energy increased with the addition of EPR, ethylene and butylene. Crystallization activation energies were calculated to be 12.05 kJ mol −1 , 12.09 kJ mol −1 , 12.38 kJ mol −1 and 12.64 kJ mol −1 for PP-1, PP-2, PP-3 and PP-4, respectively. Last but the most importantly, the addition of EPR, ethylene and butylene would enhance the impact strength, but decrease the transmittance, whereas the haze changed little. Based on the theory between structure and performance, the reason that caused above results were analyzed. This work provided some guidance for the development of high-performance polypropylene used in identical fields.