硅溶胶改性碳纤维对碳纤维/环氧树脂复合材料界面性能影响

以硅烷偶联剂和正硅酸乙酯(TEOS)为前躯体, 以固体酸-对甲苯磺酸为催化剂制备硅溶胶, 利用硅溶胶对碳纤维进行表面改性后, 以环氧树脂为基体, 制备碳纤维增强环氧树脂复合材料。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、 力学性能及碳纤维/环氧树脂复合材料的界面性能进行表征, 研究了硅溶胶改性碳纤维对其复合材料界面性能影响。结果表明, 硅溶胶处理碳纤维后, 在碳纤维表面原位生成具有膜-粒结构的表面层, 改性后碳纤维的强度由2.41 GPa提高到3.00 GPa, 界面性能也得到了明显改善, 界面剪切强度(IFSS)提高了51.41%。

Effect of surface modification by silica sol on interfacial properties of carbon fiber/epoxy composite

As the surface modifier of carbon fiber, silica sol were prepared using silane coupling agent, tetraethoxysilane(TEOS) as the precursor and p-toluenesulfonic acid(PTSA) as the catalyst. The single fiber/epoxy composite were prepared using the treated carbon fiber as the reinforcement. The carbon fibers were characterized by examination of the morphology and mechanical properties using SEM, TEM and tensile testing. Interfacial shear strength (IFSS) of the composite was measured by single-fiber fragmentation testing. The results show that a layer of the membrane-grain structure on the surface of the carbon fiber is formed in situ after being treated by the silica sol. The tensile strength of a single fiber increases from 2.41 GPa to 3.00 GPa. The interfacial properties of the composite is greatly improved and the interfacial shear strength increases by 51.41%.