中文摘要：

以高无机含量SiO2/聚甲基丙烯酸甲酯（PMMA）接枝复合材料为预分散母料,与PMMA树脂进行熔融共混,制得低无机含量的SiO2/PMMA复合材料.通过切片透射电镜（TEM）观察熔融共混过程中预分散母料内堆积SiO2粒子分散状态的演化.发现预分散母料接枝状态对其影响最为显著,不经接枝修饰的SiO2粒子经熔融共混后,不可避免地会在熔体中产生大量亚微米级的立体团聚体;复杂接枝预分散母料内构成以SiO2粒子为交联点的立体交联结构,其中的堆积SiO2粒子不能在剪切场中得到有效解离和释放;只有在使用简单接枝预分散母料时,基体高分子链才能不断地渗透扩散进入预分散母料内,而预分散母料可被不断地溶胀和撕裂,因而其中的堆积SiO2才可不断地向基体相迁移和扩散,并最终在整个复合材料内实现初级粒子形式的高度均匀稳定分散.

英文摘要：

Silica/poly（methyl methacrylate） grafting composites（SiO2/PMMA） with higher silica content were used as pre-dispersed masterbatches and melt-mixed with PMMA resin to prepare a series of SiO2/PMMA composites with lower silica content.The dispersion evolution of accumulated silica particles during melt-mixing process was monitored by section-TEM.It was found that the effect of grafting states of pre-dispersed masterbatches on the dispersibility of accumulated silica particles was obvious.Non-grafted silica particles were easily agglomerated into sub-micron level aggregation in PMMA melt due to their poor compatibility.Taking silica particles as cross-linking points,three-dimensional cross-linked structure was generally formed in complex grafted pre-dispersed masterbatche,and as a result the accumulated silica particles can＇t be released and then diffused into the matrix phase.Only the simple grafted pre-dispersed masterbatche can be swelled by the matrix polymer and then be torn by the strong shear field force,in this case the accumulated silica particles can constantly migrated from pre-dispersed masterbatche phase into matrix phase,and finally can be uniformly dispersed in the entire matrix phase at a primary-particles size level.This high silica dispersion was of benefit to improving the composite properties.