Study On The Properties Of Graphene Oxide-deposited Carbon Fiber And Its Cement Based Composites

The electromagnetic radiation is more and more serious. Cement-based electromagnetic shielding material which can not only shield electromagnetic wave, but also avoid and prevent electromagnetic wave forms of spyware and hacking activities, has attracted more and more attention. Carbon fiber(CF) has excellent conductive properties and is a good electromagnetic shielding filler. In this paper, graphene oxide sheets(GO) and Fe3O4 nanoparticles were introduced onto CF surface through the electrophoretic deposition method. GO has excellent pehydrophilicity and Fe3O4 nanoparticles has good magnetic properties. Introducing GO and Fe3O4 to CF, can not only improve the dispersion of CF in the cement matrix, so as to achieve a good combination of CF and matrix, but also improve the electromagnetic shielding properties of cement based composites.Influences of GO to microstructure and properties of cement based composite were investigated. The mechanisms of the regulation of cement hydration products by GO were analyzed by XRD and SEM. The results shows that GO could regulate the microstructure of cement hydration products and mediated formation of regular shape and small size flower-like crystals, but did not change the type of hydration products. The cement stone was dense, and the pore size was small. This suggested that GO had template role and self-assembly in forming cement hydration crystals and was conducive to the formation of dense cement, which could improve the mechanical properties of cement. The properties analysis showed that GO could improve the early strength of cement. When the amount of GO reached 0.08 wt.%, the electromagnetic shielding effectiveness(SE) of cement was high, and the dominant shielding mechanism was absorption.The microstructure and properties of GO-deposited CF(GO-CF)/cement composites were investigated. The effect of GO on the interface of CF and cement was analyzed by SEM. There were many hydration crystals on the surface of GO-CF, which could reinforce the interface bonding of CF and cement. The properties analysis showed that GO-CF/cement composites' electromagnetic shielding properties and mechanical properties had been improved. When GO-CF mass fraction reached 0.4%, SE reached 34 dB. Centrifugation technique was used for separation of GO to two sizes. The comparison of properties of big size GO-CF/cement and the samll size GO-CF/cement showed that big size GO-CF/cement had better properties. There was a high SE of 36 dB. GO-CF was situ reduced by NaBH4(RGO-CF). The mechanical properties and electromagnetic shielding effectiveness of RGO-CF were both between CF/cement and GO-CF/cement.The GO and Fe3O4 was used as the electrolyte solution to introduce GO and Fe3O4 on CF(GO&Fe3O4-CF). The properties analysis showed that GO and Fe3O4 are uniformly and firmly wrapped on the surface of CF. There were many hydration crystals on the surface of GO&Fe3O4-CF, which could reinforce the interface bonding of CF and cement. The electromagnetic shielding properties analysis showed that Fe3O4 broaden the absorption band of the GO&Fe3O4-CF. When GO-CF mass fraction reached 0.4%, SE reached 36 dB.