激光对碳纤维及碳纤维/环氧树脂复合材料性能影响

采用高能激光束对聚丙烯腈（PAN）基碳纤维进行表面改性。利用SEM、EDS、FTIR、XRD、万能试验机等表征手段，对改性前后碳纤维微观形态、成分变化、物相结构、力学性能进行表征，系统地研究了激光束对碳纤维微观组织变化、性能变化等的影响规律，探索激光束对碳纤维的作用机制。结果表明，碳纤维经激光表面改性后，其表面的粗糙度和比表面积增加，碳纤维的浸润性得到提升，且激光束的功率越高、扫描速度越低，碳纤维浸润性越好。改性后的碳纤维化学成分、微观结构及官能团种类没有改变；改性后的碳纤维官能团种类没有改变，说明激光改性过程主要以物理过程为主；激光改性没有改变碳纤维的微观结构，改性后微晶尺寸略有减小，有利于改善碳纤维与环氧树脂的界面黏结性能。激光表面改性碳纤维/环氧树脂复合材料的拉伸强度和冲击强度均有不同程度的提高，当碳纤维质量分数为0.2wt%、激光改性功率为150 W时，碳纤维/环氧树脂复合材料的拉伸强度提高了59%，冲击强度提高了52%。

Effect of laser on properties of carbon fibre and carbon fibre/epoxy resin composites

The surface of polyacrylonitrile(PAN)-based carbon fibre was modified by high energy laser beam. SEM, EDS, FTIR, XRD, and tensile testing machine were used to characterize the morphology, change of composition, phase structure, and mechanical properties of carbon fibre before and after modification. The effect of laser beam on changes of carbon fibre microstructure was systematically studied to explore the mechanisms of laser beam on carbon fibre. The results show that surface roughness, specific surface area and infiltration of carbon fibre are improved after laser surface modification. When the power is higher, scanning speed becomes lower, carbon fibre wettability exhibits better. There are no changes in chemical composition, microstructure and type of functional groups of the modified carbon fibre. The type of functional group of modified carbon fibre is not changed, which indicates that process of laser modification is mainly based on physical process. The laser modification does not change the microstructure of carbon fiber. A slight decrease in microcrystalline size is beneficial to improve to the interfacial adhesion properties between carbon fiber and epoxy resin. The tensile strength, impact strength of modified carbon fibre/epoxy resin composites are also improved. When the mass fraction of carbon fibre is 0.2wt% and modified power is 150 W, the tensile strength of carbon fibre/epoxy resin composite increases by 59%, and the impact strength increases by 52%.