聚丙烯腈基碳纤维石墨化程度对其电阻率的影响

以市面常见的6种碳纤维发热电缆为实验材料,利用拉曼光谱技术对实验材料的石墨化程度进行表征,利用数字源表(吉时利2400型)测定每组样品的电阻,以得到样品的电阻率。结果表明:当碳纤维的石墨化程度越高时,其电阻率越低。这是因为石墨化程度越高时,碳纤维成分中石墨碳的含量越高,与此同时碳纤维中非晶态过渡碳结构的芳环共轭程度增加,使π电子的迁移能力增强。随着碳纤维石墨化程度的增加,六元碳层面内的碳碳键距离增大,共价电子向传导电子转移,禁带变小,导带增大。另外,石墨化程度的增加意味着在碳纤维内部石墨的取向越来越好,故而致使电阻率降低。

Influence of graphitization degree of PAN based CF on its resistivity

Six kinds of common carbon fiber(CF)heating cables on the market were used as experimental materials.The graphitization degree of the materials was characterized by raman spectroscopy,and measuring the resistance of each group of samples with ghisley 2400.The results shown that the higher the graphitization degree of CF,the lower the resistivity of the sample.This was because the higher the graphitization degree,the higher the content of graphite carbon in the CF composition.At the same time,the degree of aromatic ring conjugation of amorphous carbon structure in CF increased,which made theπelectron migration ability enhanced.In addition,with the increase of graphitization degree,the carbon bond distance in the six carbon layer increased.When covalent electrons transfered to conduction electrons,the band gap decreased and the conduction band increased.Finally,the increasing graphitization degree meant that the orientation of graphite inside the CF was getting better and better,so the resistivity was reduced.