聚丙烯接枝马来酸酐改性纳米ZnO/聚丙烯复合材料的成核结晶行为及力学性能

采用熔融共混法制备了nano-ZnO/聚丙烯(PP)复合材料,研究了相容剂聚丙烯接枝马来酸酐(PP-gMAH)的加入对nano-ZnO/PP复合材料的成核结晶行为、晶体结构、结晶形态以及力学性能的影响。结果表明,低添加量(质量分数小于5%)的nano-ZnO对PP有较好的β晶成核效应,而当其质量分数大于5%时,nano-ZnO对PP结晶有明显的异相成核作用,使PP结晶温度大幅度提高,PP结晶在(040)晶面呈现生长择优性;PP-gMAH的加入增强了nano-ZnO粒子与PP基体之间的界面相互作用,改善了纳米粒子的分散性,促进了PP基体的异相成核,提高了nano-ZnO/PP复合材料的拉伸强度和冲击强度,但却抑制了nano-ZnO诱导PP生成β晶。nano-ZnO/PP复合材料体系中因界面相互作用改善所致的韧性提高明显强于nano-ZnO诱导PP形成β晶的增韧效应。

Nucleation and crystallization and mechanical properties of nano-ZnO/polypropylene composites modified by maleic anhydride grafted polypropylene

A series of nano-ZnO/polypropylene (PP) composites were prepared via melt blending.The effect of compatibilizer maleic anhydride grafted polypropylene (PP-g-MAH) on nucleation and crystallization behavior, crystal structure, morphology and mechanical properties of nano-ZnO/PP composites was investigated.The results show that nano-ZnO has good effect on the β-crystal nucleation of PP when nano-ZnO is added in low level (mass fraction less than 5%).When the mass fraction of nano-ZnO is more than 5%, nano-ZnO has obvious heterogeneous nucleation effect on PP matrix, with the cryatallization peak temperature of PP shifted to higher temperature significantly, and PP presents preferential growth in (040) crystal face.PP-g-MAH enhances the interfacial interaction between nano-ZnO particles and PP matrix, which improves the dispersion of nanoparticles, and promotes the heterogeneous nucleation of PP matrix.Consequently, the tensile strength and impact strength of nano-ZnO/PP composites are improved obviously.However, the ability of β-crystal induced by nano-ZnO is inhibited.The toughness of nano-ZnO/PP nanocomposites improved due to better interaction interface is significantly stronger than the β-crystal toughening effect induced by nano-ZnO.