Polypyrrole coated carbon fiber/ magnetite/ graphene oxide reinforced hybrid epoxy composites for high strength and electromagnetic interference shielding

Carbon fiber reinforced polymer composites (CFRPs) are in huge demand in the aviation industry for reducing fuel consumption despite their unfavorable electromagnetic interference (EMI) shielding properties. The present work aims to improve the mechanical properties and EMI shielding effectiveness (SE) of polypyrrole (PPy) coated carbon fibers/graphene oxide (GO)/magnetite nanoparticles (MP)/ epoxy hybrid composites. For this purpose, PPy was coated on desized woven carbon fibers (CFs) woven mats via electrophoretic deposition. Graphite oxide and magnetite nanoparticles were synthesized through improved Hummers’ method and modified Massart's method, respectively. GO was synthesized via ultra-sonication of graphite oxide, with its average thickness determined to be ∼ 1.4 nm as verified by atomic force microscopy (AFM). Solution mixing method and vacuum centrifugal mixing were utilized to disperse GO in epoxy resin. Porosity-free composites were fabricated using the vacuum bag technique. PPy coating, graphite oxide, GO and MP were characterized by scanning electron microscopy (SEM), AFM and Fourier transform infrared spectroscopy (FTIR). The SEM images showed the globular morphology of the deposited PPy on CFs. Hybrid composites containing CF_PPy-0.2 wt% GO-0.2 wt% MP showed ∼52%, ∼24%, ∼60% and ∼25% increase in tensile strength, Young's modulus, toughness, and elongation, respectively, compared to neat CF-epoxy composite. All hybrid composites prepared in this work have SE > 30 dB and could be promising lightweight and high-strength materials for EMI shielding applications in the X-band frequency range.