中文摘要：

通过熔融共混过程中原位接枝的方法制得聚丙烯酸丁酯接枝改性纳米二氧化硅/聚丙烯复合材料,并探讨了制备复合材料的最佳加工条件,研究了复合材料的机械性能、结晶性能、微观形貌以及动态粘弹行为.结果表明,少量纳米粒子（质量分数≤3%）的加入即可对聚丙烯起到同时增强增韧的作用,制备原位接枝改性纳米二氧化硅/聚丙烯复合材料的适宜加工条件为熔融共混温度180℃,共混时间10min,转子转速60r/min.结晶行为的研究表明,除了一些纳米粒子作为成核剂,大部分纳米粒子可能分布在基体的无定形相并起到物理交联的作用.微观形态观察表明,在拉伸和冲击作用下,因与聚合物基体间具有良好的界面结合,改性纳米粒子从基体中脱粘时引发基体发生强烈的塑性变形,从而吸收大量的能量,并阻碍裂纹的扩展,对聚丙烯起到增强和增韧的作用.动态粘弹行为的研究进一步说明改性纳米粒子与基体之间的界面相互作用得到大大加强.

英文摘要：

Nanocomposites consisting of polypropylene homopolymer filled with in-situ grafted nano-silica were prepared by a conventional melt compounding technique. The influence of processing conditions on mechanical properties of the nanocomposites was discussed. The mechanical performance,crystallization behaviors,morphology and dynamic mechanical behaviors of the nanocomposites were studied. It can be concluded from the results that the notched Charpy impact strength is significantly increased and toughening effect can be attained by adding low loading （mass fraction ≤3%） of the in-situ grafted nanoparticles. Meanwhile,the tensile strength can also be increased. The reasonable processing conditions of mixer can be set as 180℃ for 10min and rotation speed of 60rpm. The in-situ grafting polymerization makes dispersion of silica in the polymer matrix become much more homogeneous. Filler/matrix interaction will be enhanced due to interdiffusion and entanglement between the grafting polymer and the matrix. Studies on crystalline characteristics imply that besides some nanoparticles can be as nucleation agents; most nanoparticles might be distributed in the amorphous phase of the matrix and play physical crosslinking roles. Upon the applied tensile or impact stress,the modified nano-silica can induce great plastic deformation of the surrounding matrix,leading to absorbing substantial energy and block crack propagation. Studies on dynamic viscoelastic behavior also indicate the strong filler/matrix interface interaction.