Characteristic of Porous Carbon Fiber and its Microwave Absorption as Filler for Composite

Abstract

As a specific morphology, the porous carbon fiber was prepared through carbonization of polyacrylonitrile/polymethyl methacrylate (PAN/PMMA) blend fiber with the PAN weight of 70%. The morphology and crystalline structure of the obtained porous carbon fibers were investigated by SEM, XRD, and Raman. The obtained porous carbon fiber produced at carbonization temperature of 1000-1400°C as well as the solid carbon fiber were cut into millimeter size and used as fillers to add to epoxy in order to make composite with the weight of 6%. The complex permittivity of these composites was measured using a network analyzer. The results reveal that the cross section of obtained carbon fiber from PAN/PMMA (70/30) is full of pores with size of 0.1-1um. The graphite crystalline degree becomes high with increasing the carbonization temperature. The composite filled by the porous carbon fiber shows better microwave absorption than that filled by the solid carbon fiber, the lowest reflection loss is-24.5dB and the band width with reflection loss below-10dB is 1.9GHz as the porous carbon fiber is the filler. Among three carbonization temperature: 1000°C, 1200°C, 1400°C, the porous carbon fiber prepared at 1200°C gives the best microwave absorbing performance.