Interface Modification And Properties Of PAI-based Coatings For CF/PEEK Composites

Carbon fiber reinforced polyetheretherketone composite materials have good dimensional stability and excellent mechanical properties,and are widely used in military fields such as aerospace.However,the polyether ether ketone molecular chain is rigid,the melt viscosity is high,the surface of the carbon fiber is inert,non-polar,and the surface energy is low.The characteristics of the carbon fiber reinforced composite interface are easy to debond and the interface adhesion is poor,which seriously affects the composite.The mechanical properties of the material.In this paper,thermoplastic polyamideimide(PAI)and long-chain silane coupling agent octadecyltrimethoxysilane(OTE)are used to coat oxidized carbon fiber separately,based on the coating of polyamideimide,The self-made Ti3C2 TxMXene and polyamideimide mixed coating is applied to the oxidized carbon fiber,and the effect of different coatings on the properties of the fiber and composite materials is analyzed.The pretreatment of carbon fiber cloth uses acetone desizing,potassium permanganate oxidizes the desizing carbon fiber cloth,the pretreated fibers are coated with different mass fractions of water-based polyamideimide or octadecyltrimethoxysilane.Among them,the surface energy of the carbon fiber cloth with a coating mass fraction of 0.08 wt% PAI coating is increased by 48.91 wt%compared with the untreated,especially when the PAI concentration is 0.08 wt%,the mechanical indexes of the composite material reach the maximum,The interlayer shear strength reached 68.50 MPa,the bending strength reached 557.31 MPa,and the tensile strength reached 439.25 MPa,which was 51.52%,25.84%,and 33.35% higher than the composite material made of original carbon fiber cloth.By comparing the improvement of mechanical properties,it is proved that the coating effect of PAI is better than the modification effect of OTE.Based on the previous PAI coating research,the mixed coating of Ti3C2 TxMXene and PAI was used to coat oxidized carbon fiber.This complex coating of MXene and PAI mixed in different proportions effectively improved the carbon fiber reinforced polyether ether ketone composite.The mechanical properties,and the conductivity and shielding performance of the composite material with MXene nano-layer added as a coating have increased significantly,which has an important relationship with MXene’s unique two-dimensional nanostructure,good mechanical properties and conductivity.When the mass fraction of MXene is 1.50 wt%,the surface energy of the carbon fiber coated with the mixed coating of MXene and PAI is increased by 128.0% compared with the untreated.When the MXene mass fraction is 1.00 wt%,the mechanical properties of the composite material reach the maximum value,and the interlayer shearThe shear strength reached 82.00 MPa,and the bending strength reached 649.10 MPa,which was 96.57% and 87.17% higher than the composite material made of original carbon fiber cloth.The electrical conductivity reached 3.25 S/cm and the electromagnetic shielding performance reached 43.10 d B,which was 95.90% higher than the untreated composite material.The addition of MXene nano-layer provides a positive effect for the production of carbon fiber reinforced polyether ether ketone composite materials with good mechanical properties and electromagnetic shielding properties.