聚酰亚胺基碳纤维的制备及两者结构关联性研究

Carbon fibers are important strategic materials,the properties of which are highly depending on the chemical structure of the precursors.The theoretical analysis of the structure of Polyimide (PI) and the results of previous studies indicated that PI has outstanding properties for graphitization, and that PI is expected to be the precursor of carbon material with high-thermal conductivity. Based on the applicants' years of experience of preparing PI and carbon fibers and previous works,a research formulation has been proposed-Prepare the PI-based carbon fibers with high-electrical and thermal conductivites via carbonizing and graphitizing of homemade and strutural controllable PI fibers.PI fibers with different chemical and aggregation structure (orientation, crystallinity, etc.)will be prepared by molecular design and spinning process control. The evolution of chemical and aggregation structures during carbonization and graphitization will be investigated, and the carbonization and graphitization process will be prelininary optimized. We will focus on the effect of PI's structre on the structure and properties of the prepared carbon fiber.Some scientific problems, such as the relationship between the intrinsic structure of PI and PI-based cabon fiber and structural evolution mechanism during heat treatment, will be solved.This project will broad the precurosr sources for synthesing carbon fibers, offer scientific foundation and experimental basis for preparing PI-based carbon fibers and enrich the theory of carbon materials.

碳纤维是重要的战略物资，其前驱体结构是影响碳纤维性能的重要因素之一。聚酰亚胺（PI）结构的理论分析和前人研究结果表明：PI具有优异的石墨化特质，有望成为高导热碳材料的前驱体。申请者基于在PI纤维和课题组成员碳纤维制备方面的多年工作积累，通过前期研究探索，提出以自制、结构可调控的PI纤维为前驱体，通过碳化和石墨化制备高导电高导热碳纤维的研究思路。通过分子设计和纺丝工艺控制，制备具有不同化学结构和凝聚态结构（取向度、结晶度等）PI纤维，跟踪其在碳化和石墨化过程中化学结构与凝聚态结构的演变过程，并对碳化和石墨化工艺进行初步优化，重点研究PI纤维结构对碳纤维结构与性能的影响。解决PI纤维本征结构与碳纤维结构的相关性及热处理过程中结构的演变机制等关键科学问题。为拓宽碳纤维原材料来源提供新思路，为PI基碳纤维的制备奠定一定的科学和实验基础，丰富碳材料理论。

碳纤维是重要的战略物资，其前驱体结构是影响碳纤维性能的重要因素之一。聚酰亚胺（PI）结构的理论分析和前人研究结构表明：PI具有优异的石墨化特技，有望成为高导热碳材料的前驱体。本课题通过分子设计和纺丝工艺控制，制备不同化学和凝聚态结构PI纤维，并研究其结构和性能；经高温碳化得到PI基碳纤维，所制备的PI基碳纤维碳纤维表面光滑，结构致密，含碳量95%以上，碳收率50%以上，具有良好导电性能；优化碳化工艺，跟踪PI纤维碳化和石墨化过程中结构和性能演变过程，随碳化温度升高，PI结构发生分子链断裂生成苯基自由基、随温度进一步升高苯基自由基碰撞重组为芳香片层，向乱层石墨结构转变；重点研究了PI纤维结构对碳纤维结构和性能的影响，PI纤维分子侧向有序度、取向度、平面规整性越高，对应碳纤维石墨结构越完善，碳收率、碳含量和导电性能越高。本课题拓宽碳纤维原材料来源，为PI基碳纤维的制备奠定一定的科学和实验基础，丰富了碳材料理论。