α、β成核剂复配对聚丙烯性能的影响

Effects ofαandβNucleating Agent Compounds on Properties of Polypropylene

对5种α成核剂以及稀土β成核剂的成核能力进行了评价,考察了单独添加α、β成核剂聚丙烯(PP)性能的差异,详细讨论了α、β成核剂复配对PP微观结构、力学性能及熔融行为的影响。结果表明,添加α、β复配成核剂PP的性能与复配成核剂中α成核剂诱导α晶型的成核能力密切相关,随着α成核剂成核能力的减弱,复配成核PP冲击强度和断裂伸长率提高,弯曲强度、弯曲模量和拉伸强度减小。差示扫描量热(DSC)分析显示,随着α成核剂诱导α晶型成核能力的减弱,β晶熔融峰强度增加。在不提高总结晶度的情况下,添加α成核剂改善PP刚性以及添加β成核剂改善PP韧性的协同效应没有出现。

The nucleated capabilities for polypropylene of 5 kinds of α nucleators, a rare earth β nucleating agent, and bicomponent mixtures of a 1：1 （w/w） α/β nucleators, were evaluated via non-isothermal crystallization. The resulted crystallization and mechanical behaviors were compared. The nucleating capability of the nucleators was characterized via DSC peak intensities for α- and t-modifications. When using compounding α/β nucleators, the mechanical properties of PP could be related with the α-formation capabilities. With weakening of capabilities of α-nucleators, impact strength and elongation at break of PP increased while flexural strength, flexural modulus, and tensile strength decreased. Mechanical performance examination in this work suggested that simultaneous improvement of both the toughness and rigidity of PP by adding α/β nucleators did not constituted a proper approach.