Study on the Skin-Core Evolvement of Carbon Fibers as a Function of Heat Treatment Temperature by Raman Spectroscopy
LIU Fu-jie1,2,FAN Li-dong1,WANG Hao-jing1*,ZHU Zhen-ping1
1.Key Laboratory of Carbon Materials, Institute of Coal Chemistry，Chinese Academy of Sciences，Taiyuan 030001, China 2.Graduate School of the Chinese Academy of Sciences, Beijing 100039, China
Abstract：The skin-core evolvement of the carbon fibers was studied as a function of heat-treatment temperature though the analysis of Raman spectroscopy of the carbon fibers surface and core.It was found that the change of the Raman spectra of the carbon fibers core was similar to that on the surface with the increase in heat-treatment temperature.At 1 600 ℃, the Rs and Rc values were almost equal, indicating that the degrees of the graphitization of the carbon fibers surface and core were almost uniform.The Rs and Rc values decreased dramatically with the increase in heat-treatment temperature, and Rs decreased more.At 2 800 ℃, the Rs value came to 0.429, lowered 77.2%, while the Rc value then came to 1.101, lowered 38.7% only.It implied that the graphitization degree of the carbon fibers was enhanced with increasing the heat treatment temperature, and that of carbon fibers surface was enhanced more.The graphite characters of the carbon of the carbon fibers surface were different from that of the carbon fibers core.The former is close to soft carbon, which is easy to graphitize, while the latter is close to hard carbon, which is difficult to graphitize, and it may be resin carbon.Skin-core structure gene Rsc(＝Rs/Rc) which denoted the skin-core degree of the carbon fibers was first brought forward and adopted.The Rsc value is between 0 and 1.When the Rsc value is equal to 1, the carbon fibers are homogenous.When the Rsc value is close to zero, there are serious skin-core structures in the carbon fibers.The Rsc value reduced linearly with the increase in heat-treatment temperature, indicating that the homogeneous degrees of the carbon fibers decreased and the skin-core degrees of the carbon fibers increased.The crystallite size of the carbon fibers surface and core increased gradually with the increase in heat-treatment temperature, but the surface’s increased more quickly, indicating that the carbon of the carbon fibers surface was easier to graphitize than the carbon fibers core.Serious skin-core structure was one of the reasons that caused the reducing of the carbon fibers’ tensile strength.
Key words：Carbon fibers;Skin-core structure;RAMAN spectroscopy;Heat treatment temperature
刘福杰1,2,范立东1,王浩静1*,朱珍平1. 用RAMAN光谱研究碳纤维皮芯结构随热处理温度的演变规律[J]. 光谱学与光谱分析, 2008, 28(08): 1819-1822.
LIU Fu-jie1,2,FAN Li-dong1,WANG Hao-jing1*,ZHU Zhen-ping1. Study on the Skin-Core Evolvement of Carbon Fibers as a Function of Heat Treatment Temperature by Raman Spectroscopy. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2008, 28(08): 1819-1822.
[1] YUE Zhong-ren(岳中仁).Carbon Technology(炭素技术).1991, 2：6. [2] YUE Zhong-ren, LI Nai-yuan, WANG Ping-hua, et al(岳中仁, 李乃元, 王平华, 等).Synthetic Fiber Industry(合成纤维工业), 1991, 14(3)：29. [3] DENG Jing-ping(邓靖平).Hi-Tech Fiber & Application(高科技纤维与应用), 2004, 29(2)：21. [4] REN Fu-zhong, L Chun-xiang, LIANG Xiao-yi, et al(任富忠, 吕春祥, 梁晓怿, 等).New Carbon Materials(新型炭材料), 2004, 19(4)：268. [5] LI Li-ya, HUANG Qi-zhong, ZHANG Hong-bo(李丽娅，黄启忠，张红波).Journal of Central South University(Natural Science)(中南大学学报·自然科学版)，2005, 36(2)：193. [6] WANG Yan-xiang, WANG Cheng-guo, ZHU Bo, et al(王延相, 王成国, 朱 波, 等).Journal of Materials Science & Engineering(材料科学与工程学报), 2005, 23(3)：325. [7] DING Hai-yan, WANG Cheng-guo, BAI Yu-jun, et al(丁海燕, 王成国, 白玉俊, 等).Materials for Mechanical Engineering(机械工程材料), 2006, 30(4)：34. [8] Huang Y, Young R J.Carbon, 1995, 33(2)：97. [9] Rzepka E, Lusson A, Ponomarev E A, et al.Carbon, 1998, 36(5)：587. [10] Angoni K.Journal of Materials Sciences, 1998, 33：3693. [11] ZHANG Hong-rui, DING Pei, GUO Xin-yong, et al(张红瑞，丁 佩，郭新勇，等).Spectroscopy and Spectral Analysis(光谱学与光谱分析)，2004, 24(5)：569. [12] HUA Zhong, WANG Yue-mei, XIAO Li, et al(华 中, 王月梅, 肖 利, 等).New Carbon Materials(新型炭材料), 2005, 20(3)：268. [13] WU Xiao-li, YUE Tao, LU Rong-rong, et al(吴小利，岳 涛，陆荣荣，等).Spectroscopy and Spectral Analysis(光谱学与光谱分析)，2005, 25(10)：1595. [14] ZHENG Rui-ting, CHENG Guo-an, ZHAO Yong, et al(郑瑞廷，程国安，赵 勇，等).Spectroscopy and Spectral Analysis(光谱学与光谱分析)，2006, 26(6)：1071. [15] Tuinstra F, Koenig J L.J.Chem.Phys., 1970, 53(3)：1126. [16] Afanasyeva N I, Jawhari T, Klimenko I V, et al.Vibrational Spectroscopy, 1996, 11：79. [17] HE Fu(贺 福).Carbon Fiber and It's Application Technology(碳纤维及其应用技术).Beijing：Chemical Industry Press(北京：化学工业出版社)，2004.256. [18] Dresselhaus M, Dresselhaus S G.Adv.Phys., 1981, 30：290. [19] Dresselhaus M S, Dresselhaus G.Topics in Applied Physics, Berlin：Springer-Verlag, 1982(Vol.50)：3. [20] Sze S K, Siddique N, Sloan J J, et al.Atmospheric Environment, 2001, 35：561. [21] Wang Y, Alsmeyer D C, McCreery R L.Chem.Mater., 1990, 2：557.
