Preparation And Properties Of ZnO Nanorods/carbon Fabric Multiscale Reinforced Friction Materials Grown By Hydrothermal Electrophoresis

Carbon fiber reinforced resin-based composites are widely used in various fields due to their high strength,high modulus,good fatigue resistance,and light weight.However,the disordered layer graphite structure of carbon fibers results in non-polar surface and poor wettability with the resin matrix,which makes it difficult to form a strong interfacial bond,so that the load cannot be effectively transmitted from the matrix to the reinforcing fibers.The growth of nano-oxides on the surface of carbon fibers has proven to be an effective multi-scale method for enhancing the interfacial properties of composites.However,the traditional method of growing nano-oxides takes a long time,which easily causes energy loss and interface defects.Therefore,a hydrothermal electrophoresis method was proposed to grow ZnO nanorod multi-scale reinforced resin-based composites on the surface of carbon fabric.The rapid growth process and principle of the hydrothermal electrophoresis method were explored,and the mechanical properties and friction properties of the composites were studied.Hydrothermal electrophoresis was used to grow ZnO nanorods on the surface of the carbon fabric.Controlled growth of ZnO nanorods were achieved by changing the electrophoresis time(15 min,30 min,45 min,60 min).The structure of ZnO nanorods/carbon fabric was characterized by X-ray diffraction,Raman spectroscopy,and infrared spectroscopy.The results show that ZnO/carbon fabric multi-scale reinforcement effectively improves the friction and wear resistance of composites.When electrophoresed for 30 minutes,the friction properties and tensile properties of the composites were the best.Compared with the original composite,its wear rate was reduced by 55.40%and tensile strength was increased by 30.10%.Hydrothermal electrophoresis was used to grow ZnO nanorods on the surface of the grafted methacrylic acid-based carbon fibers.The effects of growing ZnO on the surface of non-destructive modified carbon fibers on the properties of composites were explored.The results show that ZnO nanorods grow orderly on the surface of carbon fibers via C-O-Zn bonds.Compared with the original carbon fiber composites,the tensile strength and flexural strength of ZnO nanorods/carbon fiber braided composites(CP-2)were increased by 67.5%and 31.4%,respectively.In addition,the sample CP-2 has the lowest wear rate,which is 49.7%lower than the original carbon fiber composite.The results show that the growth of ZnO nanorods on the surface of non-destructive grafted methacrylic carbon fibers effectively improves the mechanical and tribological properties of the composites.Polyethyleneimine(PEI)was grafted onto the surface of the carbon fibers on which ZnO nanorods were grown by chemical grafting.PEI has a large number of active groups such as amino and imino groups,which can react with the alcoholic hydroxyl groups of the phenolic resin matrix,increase the interlayer cross-link density,and achieve the synergistic effect of mechanical meshing and chemical bonding between the carbon fiber and resin matrix interface,effectively improves the performance of composites.Compared with the original carbon fiber composite,the tensile strength and flexural strength of the grafted PEI carbon fiber reinforced composite have been increased by 155%and 69%,respectively.Besides,the continuous friction coefficient is relatively stable,the dynamic friction coefficient is the largest,and its wear rate is only 1.2×10-5 m3/(N·m),the wear rate is reduced by 59%.