Study On Secondary Sizing Process And Performance Of Domestic Carbon Fiber

As a kind of high performance fiber, carbon fiber has many excellent properties, and has got a wide range of applications in the field of 3D textile composites. But because of it belongs to brittle material with small elongation at break, so the breakage of fiber and surface hairiness will increase after friction in the process of weaving complex fabric, and will reduce the weavability and affect the performance of the fabric and composite material. So using the method of secondary sizing to increase the weavability of domestic carbon fiber in this paper. The paper mainly studied three kinds of sizing agent, including water-soluble-type epoxy resin, polyvinyl alcohol and the mixture of water-soluble-type epoxy resin and polyvinyl alcohol. And through the adjustment of the sizing process, the concoction of sizing agent, and the test of the performance (abrasion resistance, rigidity, tensile breaking strength, surface morphology, surface hairiness after friction and cluster ability) of different fiber after sizing. Finally determine the sizing process and the optimal formulation of sizing agent.Firstly, we determined the pressure of sizing and the concentration range of sizing agent through the study of secondary sizing process. Then, testing the performance of fiber after secondary sizing, the results show that:The optimum formulation of water-soluble-type epoxy resin sizing agent is that the additive content is 5%, the concentration of sizing agent is 4%. In this condition, the number of abrasion resistance of carbon fiber is 1.68 times of the fiber without secondary sizing, and tensile breaking strength is 1.32 times of the fiber without secondary sizing. The optimum formulation of polyvinyl alcohol sizing agent is that the additive content is 10%, the concentration of sizing agent is 4%. In this condition, the number of abrasion resistance of carbon fiber is 1.41 times of the fiber without secondary sizing, and tensile breaking strength is 1.82 times of the fiber without secondary sizing. The optimum formulation of sizing agent mixed with water-soluble-type epoxy resin and polyvinyl alcohol is that the concentration of sizing agent is 4%, mass fraction of polyvinyl alcohol is 10%, the mass fraction of organic silicone finishing agent is 5%. In this condition, the comprehensive performance of sized carbon fiber is excellent, and it is beneficial to weaving.Based on the orthogonal experiment design of sizing agent mixed with polyvinyl alcohol and water-soluble-type epoxy resin, we reach the relationship between the influence factors and the performance of carbon fiber as follows:(1) With the increasing of the concentration of sizing agent, the rigidity of carbon fiber will increases gradually, the number of abrasion resistance and tensile breaking strength before abrasion and after abrasion will increase first and then reduce; (2) With the increasing of the mass fraction of polyvinyl alcohol, the number of abrasion resistance of carbon fiber and tensile breaking strength after abrasion will increase first and then reduce, the rigidity and tensile breaking strength before abrasion will increase gradually; (3) With the increasing of the mass fraction of organic silicone finishing agent, the number of abrasion resistance of carbon fiber and tensile breaking strength after abrasion will increase first and then reduce, the rigidity and tensile breaking strength before abrasion will reduce gradually.