中文摘要：

采用高度分散的纳米二氧化硅颗粒增韧／增强高性能环氧树脂。研究结果表明，高性能环氧树脂的力学性能随着纳米颗粒的添加能够得到明显的改善；填充14wt％的纳米二氧化硅时，复合材料的弹性模量、拉伸强度和断裂韧性分别提高了21％、17％和49％。断面观察分析发现，纳米颗粒的存在会导致环氧树脂基体发生塑性变形，如剪切带和空穴增长，这可能是高性能环氧树脂断裂韧性提高的主要原因。理论模型分析进一步证实，基体塑性变形，包括空穴增长和剪切带，应该是纳米颗粒改性高性能环氧复合材料断裂韧性增长的主要机理。

英文摘要：

This work focuses on the effect of highly-dispersed silica nanoparticles on toughening/ reinforcing high-performance epoxy resin. It is found that the mechanical properties of epoxy nanocomposites are significantly improved with adding the silica nanoparticles. Experimental results show that the elastic modulus, the tensile strength and the fracture toughness （GIC） of epoxy resin added 14wt% silica are enhanced about 21%, 17% and 49%, respectively. Scanning electron microscope observation revealed that the presence of nanoparticles may induce resin matrix plastic deformation such as shear banding and cavity growth. Theoretical analysis further demonstrates that the matrix plastic deformation, including plastic shear banding and void growth, should be the main mechanism of fracture toughness increasing of high-performance epoxy resin improved by adding silica nanoparticles.