聚丙烯腈基碳纤维及其原丝中的微孔尺寸分布  

Pore Size Distribution of Microvoids in PAN-based Carbon Fibers and Their Precursors

作　　者：李登华[1,2] 吴刚平[1] 吕春祥[1] 李永红[1] 贺福[1] 杨禹[1] 冯志海[3] 汪明[3] 李秀涛[3] 郭玉明[3] 

机构地区：[1]中国科学院山西煤炭化学研究所中国科学院炭材料重点实验室,山西太原030001 [2]中国科学院研究生院,北京100049 [3]航天材料及工艺研究所先进功能复合材料技术国防科技重点实验室,北京100076

出　　处：《分析测试学报》2010年第4期321-326,共6页Journal of Instrumental Analysis

摘　　要：利用二维小角X射线散射技术（SAXS）研究了聚丙烯腈基碳纤维及其原丝的微孔结构。结合逐级切线法、对数正态分布及麦克斯韦分布函数对2类实验样品内部微孔的尺寸分布进行了分析。结果表明，2类样品中的孔结构具有显著差别，原丝微孔在4～8nm范围内分布比较集中，碳纤维中微孔的分布区域则移向1．3～1．8nm。散射数据显示出明显的分形特征，碳纤维与其原丝的孔分形维数分别为1．33和1．55，表明原丝中具有较大的孔隙缺陷。相对于原丝，碳纤维微孔尺寸分布走向均匀和集中，前者则表现出比后者更宽的尺寸分布。就拟合方法而言，逐级切线法的解析手段容易引入误差，低角区的纤维表面散射和高角区的噪音容易对其结果造成影响。正态分布得到了比较窄的尺寸分布，但对于低尺寸区域孔隙的拟合不理想。麦氏分布在一定程度上弥补了以上不足，能够较好地拟合两类纤维样品中微孔的分布状况。Microvoids in carbon fibers and their precursors were investigated by two-dimensional small angle X-ray scattering（SAXS）. Combined with tangent method, normal distribution and Maxwellian distribution function, the pore size distribution of the microvoids in those two samples were analyzed. Result indicated that conspicuous difference existed in their scattering figures. In the aspect of pore size distribution, microvoids in precursor fibers centered in the region of 4 -8 nm, while this center moved to 1.3 - 1.8 nm in carbon fibers. FWHM of those figures showed a narrower size distribution in carbon fibers than that in the precursors, indicated a distinct transformation happened in micro- structure especially the voids inside for carbon fibers after the downstream processing. The data also indicated, for tangent method, scattering caused by density differences in the fiber surface may induced error in low angle area of Guinier plot and noises can made the data erroneous in large angle. Normal distribution showed a relatively narrow size distribution while may be erroneous in small size area due to such a small FWHM. Maxwellian distribution well solved the problems above, and displayed a pore size distribution figure for both carbon fibers and their precursors with higher credibility. Compared with other two methods, Maxwellian distributin might be a good choice in fitting the size distribution of fiber samples.

关 键 词：碳纤维 孔隙 小角X射线散射 麦克斯韦分布 

分 类 号：O571.418[理学—粒子物理与原子核物理] TQ342[理学—物理]