Effect of surface physical structures on interfacial shear strength of carbon fibers reinforced epoxy resin composite
HE Ye1,2, XIAO Jian-wen3, YAO Zhu-wei1,2, FU Ying-piao1,2, XU Liang-hua2, CAO Wei-yu1,2
1. State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China;
2. Key Laboratory of Carbon Fiber and Functional Polymer(Ministry of Education), Beijing University of Chemical Technology, Beijing 100029, China;
3. CNPC Institute of Jilin Petrochemical Company, Jilin 132021, Jilin, China
Abstract：The technique of quantitative characterization for the physical structure of the surface on PAN-based carbon fiber filaments was established through analyzing the cross sectional morphology which was obtained by scanning electron microscopic (SEM), followed by the image processing with Photoshop software and self-written Matlab program. The parameters such as the width, depth, and the number of surface groove structure were obtained by statistic calculation. Then the circularity, ratio of depth to width, density of groove structure along circle direction, and irregularity were also calculated to characterize the physical structure systematically. Furthermore, the groove structure of carbon fiber was regulated and controlled by adjusting the coagulation environment during the spinning process of PAN precursor, and it is found that the depth and width of groove structure on the surface of carbon fiber are decreased gradually, the shape of grooves also tends to flatten due to the decreased ratio of depth to width, the irregularity is decreased by about 7.5%, while the density of groove structure is increased by about 50% when the temperature of coagulation bath is increased from 25℃ to 45℃. The above carbon fibers with different surface physical structures were used as reinforcements to prepare composites, the results of microdroplet debonding test indicate that the interfacial shear strength (IFSS) of composites is increased with the increasing of groove size and aspect ratio, as well as the surface irregularity of carbon fibers.
 彭公秋,杨进军,曹正华,等. 碳纤维增强树脂基复合材料的界面[J]. 材料导报, 2011, 25(7):1-4. PENG G Q, YANG J J, CAO Z H, et al. The interface of carbon fiber reinforced resin matrix composite[J]. Materials Review, 2011, 25(7):1-4.
 杨景锋,王齐华,杨丽君,等. 纤维增强聚合物基复合材料的界面性能[J]. 高分子材料科学与工程, 2005, 21(3):6-10. YANG J F, WANG Q H, YANG L J, et al. Interfacial properties of fiber-reinforced polymer composites[J]. Polymer Materials Science and Engineering, 2005, 21(3):6-10.
 张敏. 碳纤维增强树脂基复合材料界面结合强度关键影响因素研究[D]. 济南:山东大学, 2010. ZHANG M. Study on the key factors of interfacial bonding strength of carbon fiber reinforced resin composites[D]. Jinan:Shandong University, 2010.
 QIAN X, ZHI J H, CHEN L Q, et al. Effect of low current density electrochemical oxidation on the properties of carbon fiber-reinforced epoxy resin composites[J]. Surface & Interface Analysis, 2013, 45(5):937-942.
 SONG W, GU A J, LIANG G Z, et al. Effect of the surface roughness on interfacial properties of carbon fibers reinforced epoxy resin composites[J]. Applied Surface Science, 2011, 257(9):4069-4074.
 张均,李常清,赵振文,等. 液/固转化过程对PAN纤维晶态和表面结构的影响[C]//中国宇航学会第十四届全国复合材料学术会议论文集. 宜昌:中国宇航学会, 2006:164-167. ZHANG J, LI C Q, ZHAO Z W, et al. Effect of liquid-solid conversion on crystal and surface stucture of polyacrylonitrile fiber[C]//China Aerospace Society Proceedings of the 14th National Conference on Composite Materials. Yichang:China Aerospace Society, 2006:164-167.
 葛曷一. 聚丙烯腈原丝与碳纤维结构相关性研究[D]. 济南:山东大学, 2007. GE H Y. Study on the structural correlation between polyacrylonitrile precursor and carbon fiber[D]. Jinan:Shandong University, 2007.
 YAO Y, CHEN S H. The effects of fiber's surface roughness on the mechanical properties of fiber-reinforced polymer composites[J]. Journal of Composite Materials, 2013, 47(23):2909-2923.
 李东风,王浩静,贺福,等. T300和T700炭纤维的结构与性能[J]. 新型炭材料, 2007, 22(1):59-64. LI D F, WANG H J, HE F, et al. Structure and properties of T300 and T700 carbon fibers[J]. New Carbon Materials, 2007, 22(1):59-64.
 赵学莹. 国产碳纤维组织结构及其复合材料界面结构与性能表征[D]. 哈尔滨:哈尔滨工业大学, 2010. ZHAO X Y. Characterization on structure of China-made carbon fiber and interfacial structure and properties of its composite[D]. Harbin:Harbin Institute of Technology, 2010.
 QIAN X, ZOU R F, OUYANG Q, et al. Surface structural evolvement in the conversion of polyacrylonitrile precursors to carbon fibers[J]. Applied Surface Science, 2015, 327:246-252.
 郭云霞,刘杰,梁节英. 电化学改性PAN基碳纤维表面及其机理探析[J]. 无机材料学报, 2009, 24(4):853-858. GUO Y X, LIU J, LIANG J Y. Modification mechanism of the surface-treated PAN-based carbon fiber by electrochemical oxidation[J].Journal of Inorganic Materials,2009,24(4):853-858.
 XIE J F, XIN D W, CAO H Y, et al. Improving carbon fiber adhesion to polyimide with atmospheric pressure plasma treatment[J]. Surface & Coatings Technology, 2011, 206(2/3):191-201.
 郑斌,黄娜,陈聪慧,等. 碳纤维表面物理特征图像处理方法[J]. 宇航材料工艺, 2010, 40(2):102-105. ZHENG B, HUANG N, CHEN C H, et al. Quantitative image processing method for SEM micrographs of carbon fiber[J]. Aerospace Materials & Technology, 2010, 40(2):102-105.
 郑斌,陈聪慧,黄娜,等. 碳纤维表面微观结构的定量化表征方法[J]. 宇航材料工艺, 2012, 42(2):103-107. ZHENG B, CHEN C H, HUANG N, et al. Quantitative image processing method for SEM micrographs of carbon fiber[J]. Aerospace Materials & Technology, 2012, 42(2):103-107.
 贺福. 碳纤维及其应用技术[M]. 北京:化学工业出版社, 2004. HE F. Carbon fiber and its application technology[M]. Beijing:Chemical Industry Press, 2004.