Study On Mechanical And Electromagnetic Shielding Properties Of Modified Carbon Fiber Reinforced Polymer

Carbon fiber reinforced resin matrix composites are widely used in aerospace,military products and automotive industry because of their excellent friction resistance,light weight and high specific strength.Although carbon fiber composites have the advantages of light weight and high strength,they also have some problems,for example,the combination strength of fiber and resin is low;the fiber may easily occur in the resin with serious agglomeration behavior;the electromagnetic shielding interference(EMI)efficiency of the material still needs to be improved.etc.The existence of these problems makes its application in China's automotive industry,military products and other fields is limited.In this dissertation,carbon fiber fabric/Thermoplastic polyurethane elastomers(CFf/TPU)and carbon fiber fabric/Graphene oxide/Thermoplastic polyurethane elastomers(CFf/GO/TPU)were prepared by a combination of layer stacking and high temperature hot pressing.Carbon fiber fabric/Graphene oxide/Thermoplastic polyurethane elastomers(CFf/GO/TPU)composites.The surface modification of CF was carried out by two different methods,and the morphology and elemental characterization of CFf/TPU and CFf/GO/TPU samples were carefully investigated,and the mechanical and EMI properties of the prepared materials were elaborated.The main research contents and the results obtained in the thesis are as follows:(1)The surface of CF was modified with KH-550 molecules,and multilayer CFf/TPU samples were prepared,and various morphological and elemental characterization,strength and EMI performance tests were carried out.The analysis of the characterization results revealed that the adhesion of KH-550 molecules to the CF surface roughened the CF surface profile,resulting in a large amount of mechanical locking effect between CFf and TPU,which in turn improved the performance of the CFf/TPU samples.(2)The CFf/TPU composites with different stacking angles and number of stacking layers were prepared by improving the preparation method,and the effects of stacking angles and number of stacking layers on CFf/TPU materials were analyzed.It was found that different CFf stacking layers and stacking angles could improve the strength and EMI performance of CFf/TPU materials.This indicates that the CFf/TPU samples exhibit angular anisotropy and their performance fluctuates with the fluctuation of CFf stacking angle.However,the electrical conductivity of the CFf/TPU sample does not fluctuate significantly with the stacking angle,which means that it does not exhibit significant angular anisotropy in electrical properties.(3)Graphene oxide(GO)was attached to CF by spraying treatment,and the changes of CF before and after treatment were analyzed,and multilayer CFf/GO/TPU materials were prepared,and various morphological and elemental characterization,mechanical and EMI performance tests of CFf/GO/TPU samples were carried out.It was found that the adhesion of GO on CFf leads to a better bonding effect between CFf and TPU,which in turn improves the mechanical and EMI properties of multilayer CFf/GO/TPU materials.In addition,the effect of thickness on the EMI performance of CFf/GO/TPU samples was also analyzed and it was found that the EMI effectiveness of CFf/GO/TPU samples increased with increasing thickness,but the increase was not significant.Also analyzed the EMI performance of CFf/GO/TPU sample after a large number of repeated folding and releasing operations,the results show that the performance of CFf/GO/TPU sample does not show significant fluctuations,and still maintain a high SET value,indicating that the CFf/GO/TPU sample has good EMI stability.