| Carbon fiber, as a high performance fiber material in twenty-first century, its reach and application has been the focus of attention. High performance carbon fiber must be sized in the process of production. Epoxy resin emulsion is one kind of carbon fiber sizing agent widely used at present. It has excellent film forming and resin matching properties, but its thermal stability is barely satisfactory. The sizing agent is at the interface of carbon fiber composite material. So the application of the composite material under high temperature condition can be greatly influenced by the thermal stability of sizing agent. Therefore it has a great significance to develop a high temperature resistant epoxy resin emulsion sizing agent to expand the application of carbon fiber composite in high temperature field.In this paper, SO1458, AM0265, EP0409 were chosen to prepare POSS modified sizing agent by chemical doping method and ultrasonic blending method. And the effect of different type of POSS and different modification method on the rheological properties of the resin, the particle size, viscosity, stability and thermal resistance of the sizing agent, the tensile strength, surface energy and interfacial shear strength of the carbon fiber were studied. The chemical doping process was analyzed by infrared spectroscopy and X-ray photo-electron spectroscopy, and it was proved that POSS entered into the sizing agent with the form of chemical bond. By using rotational rheometer to analyze the rheological properties of sizing agent resin, found that chemical doping method can make the viscosity of the resin increased dramatically, and influence phase inversion process, lead to an increase in particle size and viscosity of sizing agent, and reduced its stability. By using Thermal gravimetric analyzer to evaluate the thermal stability of sizing agent, found that the thermal resistance of sizing agent modified with SO1458 by chemical doping method was improved. When the content of SO1458 is 5mass%, the thermal decomposition temperature of the sizing agent is increased by 22.5℃. The study of carbon fiber properties shows that POSS mainly affects the surface energy and interfacial shear strength of carbon fiber.On the basis of this study, SO1458/nano-Si O2 modified sizing agent was prepared by ultrasonic blending method. The adsorption behavior of SO1458 on the nano-Si O2 surface was analyzed by contact angle measuring instrument. Analysis of the properties of sizing agent shows that SO1458 can reduce the particle size and viscosity of sizing agent, while improving its stability. Thermal gravimetric analysis showed that the SO1458/nano-Si O2 modification could significantly improve the thermal performance of the sizing agent. And when the sizing agent contains 1mass% nano-Si O2 and1mass%SO1458, the thermal decomposition temperature of the sizing agent is increased by 31.8℃.The laser particle size analyzer, rotational rheometer and differential scanning calorimetry were used to analyze the particle size, phase structure and chemical reaction in the film forming process of sizing agent. It is found that the film forming process is composed of water evaporation stage, phase inversion stage and penetration solidification stage. The chemical reaction begins with phase inversion, and it is influenced by diffusion process. The control of the sizing temperature is the key of the sizing process. At the same time, the optimum sizing process was obtained by the orthogonal experiment. |
PDF Full Text Request