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以硅烷偶联剂KH550和正硅酸乙酯TEOS为前躯体,以固体酸对甲苯磺酸为催化剂,通过溶胶-凝胶法制备了硅溶胶;利用硅溶胶对碳纤维进行表面改性后,以环氧树脂为基体,得到碳纤维增强的环氧树脂复合材料。利用SEM、TEM、万能试验机、偏光显微镜等对表面改性前后的碳纤维形态、力学性能及复合材料的界面性能进行了表征,研究硅溶胶改性碳纤维对复合材料界面性能影响。结果显示:硅溶胶处理碳纤维后,在碳纤维表面生成了具有纳米级SiO2膜粒结构的表面层,膜粒结构中的粒子尺寸在10～20nm之间,改性后碳纤维的强度由原来的2.41GPa提高到了3.00GPa,提高了24.48%;界面性能也得到明显改善,界面剪切强度(IFSS值)提高了51.41%。
Silica sol was prepared by sol-gel method using silane coupling agent KH550 and tetraethoxysilane TEOS as precursors and solid acid p-toluenesulfonic acid as catalyst. After surface modification of carbon fibers by silica sol, Oxygen resin matrix, carbon fiber reinforced epoxy resin composite material. The morphology and mechanical properties of the carbon fibers before and after the surface modification and the interfacial properties of the composites were characterized by SEM, TEM, universal testing machine and polarizing microscope. The effects of silica sol modified carbon fibers on the interfacial properties of the composites were investigated. The results showed that the surface layer of nanosized SiO2 film was formed on the surface of carbon fiber after treated with silica sol. The size of the particles in the film structure was between 10 and 20 nm. The modified carbon fiber had a strength of 2.41 GPa To 3.00 GPa, an increase of 24.48%. The interfacial properties have also been significantly improved, and the interfacial shear strength (IFSS value) increased by 51.41%.