Abstract:In order to solve the problems of weak ? nucleation and crystal growth in the crystallization process of coal-based homo polypropylene (PP) and its resultant low impact strength, the effects of adding ? or ? nucleating agent and ?/? hybrid nucleating agent on the crystallization and mechanical properties of coal-based homo PP were studied by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and universal material tester. The results show that adding?? or ? nucleating agents will lead to certain performance defects. DSC test results show that the presence of ? nucleating agent in ?/?? hybrid nucleating agent will inhibit the generation of ? crystal type, the intensity of ? crystal melt peak will increase, and the preferential nucleation of ? crystal is also obvious in the cooling crystallization curve. Meanwhile, XRD results showed that the hybrid nucleating agent could increase the relative content of ?-crystal (K?) of coal-based homo polypropylene. The addition of ?/?? hybrid nucleating agent helped to achieve the stiffness and toughness balance of coal-based homo polypropylene at the same time. When the hybrid nucleation agent addition was 0.15 wt% (?/? ratio is 1:2), the tensile strength of coal-based homo PP increased by 15.9 %, elongation at break increased by 305.3 % and impact strength increased by 72.5 %.