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Analysis and Control of nano molecular gathering texture in the mesophase pitch

中间相沥青中纳米分子聚集织构的分析与控制

基本信息

批准号：
09650941
负责人：
KORAI Yozo
金额：
$ 2.11万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

项目摘要

Development of the transversal texture in the mesophase pitch-based as-spun at 310℃, stabilized, carbonized, calcined and graphitized fibers was examined using a high resolution scanning electron microscope (HR-SEM). The cross-sectional surface of the as-spun fiber showed randomly oriented microdomains of spherical or ellipsoidal shape with ca. 50nm long in their longer axis. Such shape and orientation of the microdomain stayed almost same up to 500℃, where the microdomain took a plate shapes with some curvatures. The heat-treatment up to 700℃ induced the connection and orientation of microdomains through the shrinkage according to the evolution of volatile gas, forming the definite domain. Some voids were also observed among the microdomains. The heat-treatment at 700℃ enhanced the growth of carbon planes and their layer stacking in the microdomain. The cross-sectional domain showed gentle curvatures in the carbonized fiber at 700℃ to 1500℃ owing to smaller hexagons. The domain shape … More was basically not changed up to graphitization. The curved domain became straight during graphitization up to 2000℃, owing to the growth of graphitic planes. The as-spun fiber was extracted with pyridine to observe its microtexture. The extracted as-spun fiber at 310℃ showed macroscopically the same random transversal texture at low magnification to that of the carbonized fiber. The microdomain in the extracted as-spun fiber was already straight and oriented in the same direction as that observed in the graphitized fiber, no curvature being observable. Two other fibers spun at 300 and 340℃ to show the radial and onion transverse textures, respectively, exhibited the same trend of as-spun and graphitized fibers. Such a series of observation suggests that the insoluble fraction frames the shape, orientation and arrangement of microdomains in the graphitized fiber. The solute fraction in the as-spun fiber formed the curvature of mesophase microdomain to be carbonized to follow the shape of the oriented insoluble fraction. The texture in the extracted as-spun fiber was maintained basically after the carbonization, although bright spurs appeared in the insoluble microdomain after the carbonization of extracted as-spun fiber. The carbonization of extracted as-spun fiber induced the very straight periphery of the shorter domain. Less bent was observable in the heat-treated fibers after extraction of as-spun fiber, suggesting the connecting roles of the soluble fraction in the growth of domain. The stacking of carbon layers observed as spurs in the microdomain is basically directed along the longer axis of the shape and alignment of microdomains. Less

用高分辨扫描电镜（HR-SEM）研究了中间相沥青基纤维在310℃初纺、稳定化、热处理、煅烧和石墨化过程中横向织构的发展。初生纤维的横截面显示出随机取向的球形或椭球形微区，微区的直径约为100 nm。50 nm长的长轴。这种微区的形状和取向在500℃时几乎保持不变，微区呈板状，并有一定的曲率。700℃以下的热处理，通过挥发性气体的析出使微畴收缩，从而诱导微畴的连接和取向，形成确定的畴。在微区之间也观察到一些空隙。700℃热处理促进了微区中碳平面的生长和碳平面的层积。在700 ~ 1500℃温度范围内，由于六边形较小，截面畴呈平缓的弯曲。域形状 ...更多信息到石墨化基本上没有变化。在石墨化至2000℃时，由于石墨面的生长，弯曲畴变直。用吡啶对初生纤维进行萃取，观察其微观结构。在低倍放大下，310℃下萃取的初生纤维在宏观上显示出与普通纤维相同的无规横向织构。提取的初纺纤维中的微区已经是直的，并且取向与石墨化纤维中观察到的方向相同，没有观察到曲率。在300 ℃和340℃下纺制的另外两种纤维，分别显示出径向和洋葱状横向织构，表现出与初生纤维和石墨化纤维相同的趋势。这样一系列的观察表明，不溶部分框架的形状，取向和石墨化纤维中的微区的排列。初生纤维中的溶质部分形成了中间相微区的曲率，并被弯曲成遵循取向的不溶部分的形状。萃取初生纤维经碳化处理后，虽然在不溶微区出现了明亮的毛刺，但其织构基本保持不变。萃取的初纺纤维的碳化导致较短畴的非常直的外围。在热处理后的纤维中观察到较少的弯曲，表明可溶性部分在畴生长中的连接作用。在微区中观察到的作为毛刺的碳层的堆叠基本上沿着微区的形状和排列的长轴定向。少