Constructing a cross-dimensional interfacial transition layer with MXene and aramid nanofiber for carbon fiber/ poly (ether ether ketone) composites interfacial enhancement

The intrinsic inert surface structure of carbon fiber (CF) results in a weak interfacial adhesion with poly (ether ether ketone) (PEEK), deteriorating the mechanical performance of CF/PEEK composites. In order to solve this longstanding obstacle, a cross-dimensional interfacial transition layer strategy is proposed, containing of aramid nanofiber (ANF), Ti₃C₂T_x MXene, and a matrix-compatibilizer of polyetherimide (PEI) to coat on CF surface. The interactions between each component contributes to constructing a uniform sizing layer on CF surface, significantly increasing the CF surface roughness and improving the wettability between CF and PEEK. Furthermore, the crystallinity of PEEK displays a slight increment and the interphase region has been expanded, forming a gradient modulus-plateau as the introduction of MXene-ANF/PEI sizing agent. These synergistically reinforcement mechanism results in the elevated mechanical performance of CF/PEEK composites. In brief, this cross-dimensional transition layer approach provides an effective route for fabricating the high-performance CF/PEEK composites.