Mechanical Properties And Electromagnetic Interference Shielding Performance Of Graphene Oxide Reinforced Carbon Fiber Fabric

With the rapid development of the electronic science and technology era,human health and environmental pollution caused by electromagnetic radiation phenomena have attracted people's attention,so it is very important to develop electromagnetic shielding materials.Compared with traditional metal shielding materials,carbon fiber material has lighter weight and stronger mechanical properties.Epoxy/carbon fiber fabrics with carbon fiber as the main raw material and epoxy resin as the coating are widely used in aerospace,automobile body,electronic sensors,and energy equipment.However,the electromagnetic shielding effect of epoxy resin/carbon fiber is often not good,so it needs to be further enhanced: first,spraying or electroless plating materials such as conductive metal on the surface of carbon fiber;second,modifying and enhancing the epoxy resin on the surface and then compounding with carbon fiber.Although these two methods have obvious effects,there are some problems with the actual production,such as difficulty in spraying/coating,a large number of consumables,difficulty in coating epoxy resin,and difficulty in secondary processing of a large number of carbon fiber semi-finished products and prefabricated products already coated with epoxy resin.This thesis adopted a cross-scale design to load graphene oxide on the surface of epoxy resin/carbon fiber using the wet transfer method to prepare graphene oxide/carbon fiber/epoxy resin composite fabric.The influence law and mechanism of graphene oxide concentration,surface functional groups,water bath temperature,and heating time for electromagnetic shielding properties of composite fabrics were studied.The method is simple to operate and convenient for large-scale production.The main research work includes:(1)The modified Hummers method was used to prepare graphene oxide sol,and the wet transfer method was used to make graphene oxide/epoxy resin/carbon fiber composite fabric.The structure and composite states of graphene oxide and composite fabric were characterized by scanning electron microscope,atomic force microscope,Fourier transform infrared spectroscopy and X-ray diffraction analysis.(2)The effects of key parameters such as water bath temperature,heating time and graphene oxide sol concentration on the structure,mechanical properties and electromagnetic shielding properties of the composite fabric were studied.The microstructure,tensile strength,tensile elastic modulus,elongation at break,inter laminar shear strength,folding resistance,electrical conductivity and electromagnetic shielding efficiency of the fabric before and after graphene oxide composite were characterized.The experimental results show that the composite fabric prepared by heating 2 mg/m L graphene oxide sols in 60 ? water baths for 2 hours has the best performance.The tensile strength,tensile modulus,and elongation at the break of the composite fabric are increased by 59.2%,16%,and 63% respectively,the folding strength is increased by 58.1%,the conductivity is increased by 14.7%,and the total shielding efficiency,absorption loss,and reflection loss are increased by 32.4%,29.6%,and 39.1% respectively.(3)Based on the work in part(2),the effects of surface functional groups of graphene oxide on fabric composite effect,composite fabric mechanics and electromagnetic shielding properties were studied: reduced graphene oxide and carboxylated graphene oxide were obtained by in-situ thermal reduction and surface carboxylation modification,and reduced graphene oxide/epoxy resin/carbon fiber and carboxylated graphene oxide/epoxy resin/carbon fiber were prepared.Compared with the original samples,the tensile strength,tensile elastic modulus and elongation at break of reduced graphene oxide/epoxy resin/carbon fiber were increased by 65.4%,55.9% and 11.8% respectively,and the conductivity was increased by 28%;Using carboxylated graphene oxide/epoxy resin/carbon fiber,the tensile strength,tensile elastic modulus,and elongation at break were increased by 60.8%,16%,and 62.4%respectively,and the conductivity was increased by 5.4%.