Development of Carbon Skeletons in Pitches

与固态碳化的聚酰亚胺和气相碳化生长的气相碳纤维相比，液态沥青中碳骨架(即中间相)的形成和生长是可以理解的。以薄膜和纤维为例，讨论了由于碳骨架的发展而产生的碳的结构和织构，以及它们在碳科学和技术中的重要性。1.碳骨架的发展碳骨架的发展强烈地依赖于沥青的化学组成和热历史。一些沥青在微观尺度上是不均匀的，各向同性相包含Brooks-Taylor类型的中间相球体和各向异性结构域，这些基本结构单元相互关联，具有长范围的统计取向。一些间距是均质的，由具有长范围统计取向的各向异性磁畴组成。2.碳材料的结构发展-…研究发现，即使纺丝成纤维后，沥青中仍存在更多的非均质和均匀的织构。例如，从含有大量边缘到边缘各向异性区域的沥青中，对横截面上具有径向织构的纤维进行纺丝，发现其织构在氧化、碳化和随后的石墨化过程中保持不变。在由聚酰亚胺制备的碳膜中，发现石墨结构的发展强烈地取决于先驱体聚酰亚胺薄膜中的分子取向。3.碳材料中的织构及其功能研究了碳材料中织构对其性能的影响，重点研究了不同织构的碳纤维在高温热处理时石墨结构的发展、与聚合物基质的相互作用以及硫酸和锂离子的插层作用。研究了碳纤维/碳基复合材料的力学性能。较少

The formation and growth of carbon skeletons, i.e., mesophase, in pitches which are in liquid state are understood in comparison with polyimides which are carbonized in solid state and vapor-grown carbon fibers which are grown in gas-phase carbonization. The structure and texture of carbons, which are resulted from the development of carbon skeletons, and their importance in carbon science and technology are discussed in the cases of films and fibers.1.Development of carbon skeletonsThe development of carbon skeletons depended strongly on chemical constitution and thermal history of pitches. Some pitches were heterogeneous at a micrometric scale, isotropic phase containing Brooks-Taylor type mesophase spheres and anisotropic domains consisting of basic structural units associated edge-to-edge with a long range statistical orientation. Some pitches were homogneous, consisting of anisotropic domains with a long range statistical orientation.2.Structure development in carbon materialsThe … More heterogeneous and homogeneous textures in pitches were found to be remained even after the spinning to fibers. From the pitch containing large amount of edge-to-edge anisotropic regions, for example, the fibers with radial texture in their cross-section were spinned, and their texture was found to be kept during oxidation, carbonization and subsequent graphitization. In the carbon films prepared from polyimides, the development of graphite structure was found to be strongly governed by the molecular orientation in the precursor polyimide films. The same situation was observed on vapor-grown carbon fibers.3.Textures in carbon materials and their functionsThe effects of texture in carbon materials on their functions were studied by focusing on the development of graphitic structure with high temperature heat treatment, the interaction with polymer matrices and intercalation of sulfuric acid and lithium ions by using carbon fibers with different textures. The mechanical properties of carbon fiber/carbon matrix composites were also studied. Less