Combined effect of modified zeolite 13X and β-nucleating agent on improving β-crystal content and toughening polypropylene random copolymer

Although addition of β-nucleating agent directly into homo-polypropylene (PPH) is a useful method to improve β-crystal content and toughen PPH, polypropylene random copolymer (PPR) makes this method powerless due to its random structure and low crystallinity. In this study, the β-nucleated PPR with high β-crystal content was prepared by a novel high effective β-nucleating system which consists of β-nucleation agent (TMB-5) and modified zeolite 13X (M13X). It was found that M13X and TMB-5 had a synergistic influence on improving β-crystal content and toughening PPR. The content of β-crystal in PPR/M13X/TMB-5 was significantly larger than the sum of that in PPR/M13X and PPR/TMB-5. Besides, fracture behavior, phase morphology and relaxation of matrix chain segments were also investigated. The results showed that M13X and TMB-5 improved the mobility of amorphous chain segments at low temperature and contributed to much energy dissipation. This work provides a powerful method to modify PPR.