黏胶纤维在热解过程中微孔结构的演变

Evolution of Microporosities in Rayon Fibers During Pyrolysis

利用同步辐射X射线小角散射（SAXS）研究了黏胶基碳纤维原丝裂解过程中微孔的变化.结果表明：裂解过程中微孔沿轴向的半径由3.88 nm逐渐增大到7.04 nm,而垂直于轴向的半径则由3.86 nm减小至3.15 nm.因而,孔形由椭圆逐渐演变成针形,且取向趋向于纤维轴方向.分形研究表明：垂直于轴向的微孔分形维数由2.40增大到2.61,而沿轴向的微孔分形维数则在2.00 ～2.23波动,说明随着裂解的进行,微孔结构逐渐趋于复杂化.微孔是影响纤维的力学性能主要因素,对纤维中的微孔结构的研究有着重要意义.

The micropores of the rayon based carbon fiber precursors were studied during the pyrolysis process. Results indicated that the longitudinal radius of the micropores increased gradually from 3.88 nm to 7.04 nm while the evolution trend of transversal radius was inverse which decreased to 3.15 nm from 3.86 nm, thus the shape of the mi- rocpores became needle. Meanwhile, the fractal dimension of transversal micropores increased from 2.40 to 2.61 and the fractal dimension of longitudinal micropores fluctuated in the process from 2.00 to 2.23, which indicated the roughness of the micropores increased gradually. The micropore is a major factor in controlling the mechanical proper- ty of fibers, therefore it＇s important to study the micropores.