Preparation And Performance Study Of The Carbon Fiber Aqueous Epoxy Sizing Agent

Carbon fiber reinforced resin(CFRP)composites are widely used in aviation,automobile,sports and other fields because of their light weight,high strength and high temperature resistance.However,the comprehensive performance of CFRP composites has not been improved with the improvement of the performance of carbon fiber.How to play the performance advantage of carbon fiber better on CFRP composites has become the focus of research.The preparation of high performance sizing agent to improve the composite is a key factor in performance.Suitable sizing agent can improve the wettability of carbon fiber surface,generate organic polymer film containing a large number of functional groups on the fiber surface,improving the interface bonding properties between the carbon fiber and resin matrix.At the same time,with the national environmental protection requirements increase,the traditional oil-soluble sizing agent gradually being replaced by environmentally friendly waterbased sizing agent become a trend.In this paper,bisphenol A type epoxy resin(E-51),triethylenetetramine(TETA),butyl glycidyl ether(BGE)and glacial acetic acid(HAc)were used as raw materials to synthesize modified epoxy Emulsifier(MEE),the influence of temperature and time on the polymerization reaction was studied by IR and so on,and the optimum parameters of the synthesis reaction were determined.The waterborne epoxy sizing agents E-1 and F-1 were prepared by emulsifying the E-51 and phenolic epoxy resin(F-51)with deionized water,and the stability,particle size distribution and thermal stability of the sizing agent was determined by thermogravimetry,centrifugation and particle size analysis.The two sizing agents have a particle size of about 130 nm,and the decomposition temperature of E-1 sizing agent is lower than 250 °C,and the decomposition temperature of F-1 sizing agent is 275 °C.The microstructure of the carbon fiber was characterized by scanning electron microscopy,atomic force microscopy,X-ray electron spectroscopy and polarized light microscopy.The surface morphology,chemical composition and the wettability of the carbon fiber sized by E-1 and F-1 were investigated.The results show that the fiber surface are coated with sizing layer containing a small amount of particles in the thickness of 50 ~ 100 nm,activated carbon atoms on the fiber surface are both increased while containing epoxy sized by the two kinds of carbon fiber after sizing treatment.The contact angles of carbon fibers treated by two kinds of sizing agent decreased to 32.90% and 36.11% respectively compared with the desized carbon fiber,and the wettability improved obviously.When the droplet height H on the fiber is 35 ~ 80?m,the droplet volume has no effect on the test results,indicating that the fiber loading method is used to characterize the wettability of carbon fiber.The tensile strength of carbon fiber monofilament treated by two sizing agents was both improved,and the discretization of F-1 sizing carbon fiber was less than that of E-1.Heat shock experiments show that sizing agent and carbon fiber have good bonding properties.Compared with the desized carbon fiber,the IFSS of the sizing of the carbon fiber epoxy(CF / EP)composite increases by 70.49% and 75.69%,respectively,the single fiber breaking method shows that the sizing agent play a good bridging role between the epoxy matrix and the carbon fiber.Unidirectional carbon fiber cloth was sized by two kinds of waterborne epoxy sizing agents E-1 and F-1,carbon fiber reinforced nylon 6(CF / PA6)composites were prepared in sandwich sandwich structure.The results show that the mechanical properties of CF / PA6 composites are improved obviously,and the tensile strength of E-CFRPA6 and F-CFRPA6 composites increases by 15.96% and 13.88% respectively,and the flexural strength increases by 37.4% and 42.18% The impact strength of the composites is increased by 14.28% and 15.8% respectively.The thermal decomposition temperature of the two composites can reach 350 °C.The above studies show that the prepared sizing agent has good sizing properties,can be used for carbon fiber reinforced polyamide composite material,can also significantly improve the interface and mechanical properties of the composite material.