中文摘要：

采用动态流变学方法研究了纳米二氧化硅（SiO2）/聚丙烯（PP）复合材料的熔体流变行为.通过探讨纳米粒子接枝改性、粒子含量和制备方法对复合材料熔体动态粘弹响应的影响,研究纳米复合材料宏观流变性质与微观结构参数之间的关系.结果表明,纳米粒子表面处理、含量和加工方法对聚合物复合材料熔体的动态粘弹响应有明显影响,低频率ω区域粘弹函数对纳米复合材料的结构变化存在敏感响应.接枝改性纳米粒子的加入使复合材料的低ω区域动态储能模量（G′）与ω的对数关系lgG′～lgω出现第二平台特征,纯PP和未改性纳米粒子填充体系中未出现此现象,证实了复合材料中纳米填料网络结构的存在,且出现填料网络结构的纳米粒子逾渗值低至0.87%（体积分数）,说明少量纳米粒子的加入即可引起复合材料结构和界面特性的变化.

英文摘要：

The rheological behaviors of nano-silica/polypropylene （PP） were studied by means of dynamic rheological tests. The development of microstructure for PP nanocomposites was investigated through examining the influence of nanoparticles treatment,volume fraction and processing method on dynamic rheological functions. Results reveal that the rheological functions vary with above factors. The viscoelasticity of nanocomposites at low frequency （ω） range is sensitive to the structure evolution. The second plateau appears in the logarithmic plots of the dynamic storage modulus versus frequency,lg G＇~lg ω,in low ω range for grafted nanoparticles filled systems,confirming the occurrence of network structure of filler in nanocomposites. Moreover,the critical filler loading for percolation for grafted nanoparticles system is less than 0.87vol%. The studies on rheological properties of nanocomposites elucidate that the microstructure and interfacial characteristics of polymeric materials could be changed by addition of small amount of nanoparticles.