PAN基碳纤维的结构对石墨化的影响-材料科学工程专业毕业论文.docx

度和模量都较高。通过工艺调控，制备出了石墨化结构参数K为1．27 度和模量都较高。通过工艺调控，制备出了石墨化结构参数K为1．27 的碳纤维，在2200。C高温处理后，纤维拉伸强度为4．5GPa，模量为 360GPa，其强度保持率为80％，模量增加为初始碳纤维的1．2倍。 关键词：PAN基碳纤维，微晶结构，径向结构，模量 万方数据 ABSTRACTEFFECT ABSTRACT EFFECT OF PAN．BASED CARBoN FIBER STRUCTURE oN GRAPHITIZATION ABSTRACT In the preparation of PAN-based carbon fiber,the change of pre—oxidation and carbonization conditions can influence the structures and also its mechanical properties．The graphitization of the carbon fiber can significantly improve tensile modulus of the fiber，but reduce its tensile strength．Therefore the regulation of the initial structures of carbon fiber can achieve the regulation of fiber structu，re in graphitizing process．To improve the modulus of carbon fiber,reducing carbon fiber strength loss at the same time is an important foundation for producing high strength and modulus carbon fiber． In this thesis，Raman spectrum and X_ray diffraction were mainly used to characterize the structure of carbon fiber and graphite fiber． Temperature dependence of carbon fiber structures Was studied systematically．Based on the study of the effect of primary crystallite structures of carbon fiber on high temperature graphitization，the relationship between carbon fiber microcrystal structure and graphite fiber structure，properties and fiber structure Was established． 万方数据 北京化工大学硕士学位论文The 北京化工大学硕士学位论文 The results showed that：晰th the increase of carbonization temperature，the change range of the carbon chemical structure and micro crystal structure appeared at 1 300(2，The degree of graphite is greatly improved，and the graphite structure integrity is enhanced．In the radial direction，the structure of the core is different，and the crystallite structure is more perfect．The carbon fiber with higher initial graphite degree achieved relatively higher degree of graphite after high temperature treatment，and the graphite structure is relatively perfect．The distribution of the radial structure is unifoITn，and the homogeneity is bett