煤基共聚聚丙烯与复合成核剂协同增强增韧聚丙烯

Synergistic Improving of Strength and Toughness of Polypropylene by Coal-Based Copolymer Polypropylene and Hybrid Nucleating Agent

利用差示扫描量热仪(DSC)、万能材料实验机等研究了α/β复合成核剂与煤基嵌段共聚聚丙烯(PPB)协同作用对均聚聚丙烯(PPH)力学性能及结晶行为的影响。结果表明,煤基PPB可在一定程度上提高PPH的冲击与拉伸韧性,且保持较高的刚性。α/β复合成核剂与煤基PPB的协同使用可以大幅度提升PPH冲击强度及断裂伸长率,这主要归功于β晶型的形成和PPB的协同增韧补强。根据DSC测试,经过退火处理的协同改性聚丙烯拥有更完善的晶体生长与β晶型,表现出较好的刚韧平衡。当PPH/PPB质量比为5∶1,α/β成核剂质量比为1∶2时缺口冲击强度超过54 kJ/m^(2),断裂伸长率超过530%且弯曲强度和拉伸屈服强度均超过30 MPa。

The synergistic effects of α/β hybrid nucleating agent and coal-based polypropylene block copolymer(PPB)on the crystallization and mechanical properties of polypropylene homopolymer(PPH)were extensively explored by differential scanning calorimetry(DSC)and multipurpose mechanical testing machine.The results indicate that PPB can improve the impact and tensile toughness of PPH to a certain extent and maintain high rigidity.The combination of α/β hybrid nucleating agent and PPB can significantly improve the impact strength and elongation at break of PPH,which is mainly attributed to the formation of β crystal in the matrix and the synergistic toughening and strengthening of PPB.According to DSC tests,the modified polypropylene after annealing has better crystal growth and β crystal form,and shows good stiffness-toughness balance.When the ratio by weight of PPH/PPB is 5∶1 and the α/β nucleating agent ratio by weight is 1∶2,the notched impact strength is more than 54 kJ/m^(2),elongation at break is larger than 530%.Meanwhile,the bending strength and tensile yield strength are both exceeding 30 MPa.