碳纤维表面特征对碳/环氧复合材料界面性能的影响

Effect of Carbon Fiber Surface Characteristics on Interfacial Properties of Carbon/Epoxy Composite

为了研究碳纤维表面特征与碳/环氧复合材料界面剪切强度的定量关系。采用扫描电子显微镜、比表面积分析仪、X射线光电子能谱仪对T800级碳纤维表面形貌、比表面积和表面化学特征进行了测试表征,并使用微珠脱粘法测试了复合材料的界面剪切强度(IFSS)。基于碳纤维比表面积测试结果,引入真实界面面积的概念,重点分析了界面面积和化学特征对IFSS的影响机理和规律。结果表明,不同表面状态的T800级碳纤维比表面积存在明显差异,两种除浆工艺处理的碳纤维比表面积相差25.4%。消除界面面积影响的真实界面剪切强度(IFSS’)与碳纤维表面氧碳比呈现出较好的线性相关性,R2达到了0.94。反映出提高碳纤维比表面积和表面氧碳比是改善复合材料界面性能的有效手段;同时,也为定量研究碳纤维表面物理和化学特征对复合材料界面性能的影响提供了一种新的分析思路。

In order to study the quantitative relationship between the surface characteristics of carbon fiber and the interfacial shear strength of carbon/epoxy composite.The surface morphology,specific surface area and surface chemical characteristics of T800-grade carbon fibers were characterized by scanning electron microscopy,specific surface area analyzer and X-ray photoelectron spectroscopy.The interfacial shear strength(IFSS)of the composites was characterized by the micro-debond test.Based on the test results of specific surface area of carbon fibers,the real interface area was calculated and taken into account,while the influence of interfacial area and chemical characteristics on the IFSS was analyzed.The results show that there are obvious differences in the specific surface area of T800-grade carbon fibers with different surface conditions,and the difference in specific surface area of the carbon fibers treated by the two desizing processes is 25.4%.It shows a good linear correlation between the real interfacial shear strength(IFSS’),calculated based on the real interfacial area,and the surface oxygen-carbon ratio of carbon fiber,and the coefficient of determination reached 0.94.It is demonstrated that increasing the specific surface area and the surface oxygen-carbon ratio of carbon fiber are effective methods to improve the interfacial shear properties of composites.Moreover,it also provides a new way to quantitatively study the influence of physical and chemical characteristics of the carbon fiber’s surface on the interfacial properties of the composites.