Modification of carbon fiber by polyacrylonitrile coating and high-temperature carbonizing treatment for enhancing fluororubber’ mechanical and electromagnetic shielding performance

In this study, to solve the problem of poor interfacial bonding between carbon fiber (CF) and fluororubber (FKM), the polyacrylonitrile (PAN) coating and high-temperature carbonizing method were proposed to modify the CF. In this method, the PAN nanospheres were compounded with carbon fiber by coating process, and then melted and carbonized to a thin carbon layer attached to the CF surface during the high-temperature carbonizing process. The rough and irregular PAN carbonized layer on C-PAN-CF can greatly enhance the mechanical performance of fluoroelastomer by mechanical riveting effect. The tensile strength, modulus at 100% strain and hardness of FKM/C-PAN-CF improved by 122.0%, 123.5% and 29.2%, respectively. And the compression set reduced to 29.5%. Furthermore, the C-PAN-CF could also raise the FKM’s thermal stability, thermal management performance and Electromagnetic shielding performance (EMI SE). Particularly in the X-band, the composites’ shielding mechanism was mainly based on reflection. In summary, such a simple and effective technique for preparing C-PAN-CF hybrid fibers provides a certain reference for the preparation of reinforcing fillers for high-performance FKM composites.