Construction of an outstanding HMCF/PEEK interface by cathodic electrophoretic deposition of PEI/MXene composite nanoparticles with excellent stability to enhance the mechanical properties of the composite materials

In recent years, electrophoretic deposition (EPD) MXene nanoparticles have been used to improve the interface performance of high modulus carbon fiber (HMCF) composites. However, the traditional cathodic electrophoretic deposition technique causes carbon fibers to oxidize, which affects the strength of the carbon fibers themselves. The unstable and easily decomposable characteristics of MXene nanosheets particularly limit the effectiveness of improving the interface performance of thermoplastic polyetheretherketone (PEEK) composites. This study adopts the cathodic electrophoretic deposition process to reduce the damage to carbon fibers; it introduces a temperature-resistant antioxidant polyethyleneimine (PEI), and combines MXene with it through hydrogen bonds and electrostatic interactions to prepare a water-based PEI/MXene nanoparticle dispersion with positive surface charge and excellent thermal stability. These nanoparticles meet the requirements of the cathodic electrophoretic deposition process and the processing of HMCF/PEEK composites. The surface energy of PXM-HMCF is 174.93 % higher than that of D-HMCF. PMX provides a rigid mechanical locking structure at the interface and a flexible modulus transition layer, which increases the interlayer shear strength (ILSS) of PMX-HMCF/PEEK composites to 70.66 MPa, which is 63.22 % higher than that of D-HMCF/PEEK (43.29 MPa). The bending strength of PMX-HMCF/PEEK composites also increases by 22.77 %.