中间相沥青及其炭纤维的显微结构和性能

THE MICROSTRUCTURE AND PROPERTIES OF THE MESOPHASE PITCHES AND THEIR CARBON FIBRE

中间相沥青基炭纤维(CF)的力学性能受中间相沥青的微结构和不熔化、炭化。石墨化过程的影响。本文考察了几种不同原料的中间相沥青的微观结构,乙沥渣油两个馏份的中间相沥青为细镶融并体,是难石墨化物质,而T渣油E馏份中间相沥青是由小球有序堆积形成的一种大的各向异性融并体,是易石墨化物质,中间相的不同结构直接影响CF的力学性能.用电子显微镜观察了CF的结构形态,由T渣油E馏份制成的中间相沥青炭纤维呈现放射状的径向结构,并存在孔隙裂纹.它们主要取决于中间相沥青的原料和不熔化、炭化和石墨化的工艺条件,最终影响CF的力学性能。

The mechanical properties of the mesophase pitch based carbon fibre are strongly affected by the microstructure of mesophase pitch and the processes of stabilization, carbonization and graphitization. In this work, the micro- structures of several mesophase pitches prepared from different precursors have been examined. Two fractions separated from ethylene tar form a fine grained-stringy coalesced mesophase typical of poorly-graphitizating materials; the E fraction of T residual oil shows a mesophase development typical of well- graphitizing substances, namely,the growth and coalescenece of ordered sphe- rules to give a large-grained anisotropic phase. The difference in mesophase microstructure directly relates to the mechanical properties of carbon fibre. The morphological features of carbon fibre were observed by SEM. Carbon fibre prepared from the mesophase pitch of T residual's E fraction exhibits a radial transverse structure that the cracks and flows occur in the filament. The cracks and flows which depend fundamentally on the composition of mesophase pitch and the processes of stabilization, carbonization, and graphi- tization also influence the mechanical properties of carbon fibre.