Preparation Of CFF/PEEK Composites And Research On Interfacial Wettability

Poly ether ether ketone?PEEK?is a high performance semi-crystalline thermoplastic polymer with regular structure.It has excellent mechanical properties,high temperature resistance,corrosion resistance and flexibility.The thermoplastic composites reinforced with carbon fiber cloth?CFF?have excellent dimensional stability and corrosion resistance.Aerospace has great application potential.However,because carbon fibers are relatively stable six-membered ring structure,there are fewer active functional groups on the surface of the fibers,and the activation energy is low;while PEEK molecular chains are rigid and non-polar melt state viscosity is high,both of them cause poor interfacial wettability,easy interlaminar damage,and composite materials do not play a real role.At the same time,the impact resistance is also an important problem in the application of CFF/PEEK structure.The impact will cause serious delamination within the material,which will greatly reduce the mechanical properties of the composites.Improving the toughness of PEEK resin can greatly improve the impact resistance of CFF/PEEK composites.In this paper,CFF and PEEK membranes are made into composite materials by moulding.The optimum moulding process of CFF/PEEK is studied.The conclusion is as follows:the moulding temperature is 370?for 40 minutes,the temperature is lowered to 290?for 90 minutes,and then it is cooled in air naturally.The whole moulding pressure is 0.5 MPa without setting temperature gradient and resin content.40%⁴4%.Using water-soluble polyamide imide?PAI?as sizing agent,adding functional additive PEEK and dispersant trichloromethane to form emulsion to size CFF after surface oxidation with KMnO₄.The tensile strength of carbon fiber monofilament is 0.73%higher than that of desizing carbon fiber.Sizing makes the surface of CFF introduce active groups and surface energy.It was 30.01%higher.The tensile strength and flexural properties of CFF/PEEK are increased by 40.29%and 5.54%,respectively.CFF/PEEK with interlaminar damage can continue to bear loads,and the interlaminar shear strength is increased by 32.12%.Poly ether sulfone?PES?was blended with PEEK by solution blending method.The compatibility and crystallinity of PES and PEEK blends were studied by DSC.PES effectively inhibited the crystallization of PEEK.The heat resistance of the blended resin is similar to that of PEEK,but it still has good heat resistance.After sizing,PAI not only affects the toughness of the interface,but also increases the toughness of CFF/PEEK by absorbing energy as interlayer adhesive,which is much better than the original one.At the same time,the PEEK content of 70%blends is better than the other three composites in damage resistance and damage tolerance,and the toughness is better.