An anchor-inspired interface for improving interfacial properties of carbon fiber-reinforced high-performance thermoplastic composites

Carbon fiber-reinforced thermoplastic composites are promising materials with many application prospects. However, surface inertness of CFs weakens the interfacial properties of these composites. Therefore, in this study, an anchor-inspired structure was designed and grafted onto CFs by using an anchor-inspired segmented copolymer, comprising of polyimide as the "chain" and polyhedral oligomeric silsesquioxane (POSS) as the "anchor". In combination with atom transfer radical polymerization with the advantage of controllable molecular weight, degree of polymerization of the anchor-shaped structure with the best compatibility with poly (phthalazinone ether nitrile ketone) (PPENK) resin was pre-determined through molecular dynamics simulations, which reduced the experimental costs. The results of X-ray photoelectron spectroscopy indicated the successful connection of the numerous anchor-shaped structures to the CFs. Compared to composite made of origin fibers and PPENK, the interfacial shear strength at the microscopic level and interlaminar shear strength at the macroscopic level of grafted CF and PPENK composite increased by 184.9 % and 44.2 %, respectively. This is mainly attributed to the synergistic effect of mechanical interlocking and interfacial interaction between the anchor-shaped structure and the PPENK resin. This study serves as a feasible path to enhance the interfacial adhesion of composites by designing an anchor-shaped structure of organic macromolecules and inorganic nanoparticles on CFs.