Interfacial modification and tribological properties of carbon fiber grafted by TiO2 nanorods reinforced novel depolymerized thermosetting composites

In this study, homogeneous and dense TiO2 nanorods (TiO2 NRs) were grafted onto carbon fiber (CF) simply by hydrothermal method to enhance the interfacial bonding between CF and poly(hexahydrotriazine)s (PHTs) matrix and improve the tribological properties of CF reinforced polymer composites (CFRPs). The oriented TiO2 NRs impacted the mechanical properties by supplying mechanical interlock. As growth of TiO2 NRs increased, the tensile strength and modulus enhanced by about 31.8% and 15.1% when compared to neat CF. Most importantly, the wear rate of PHT/TiO2@CFC reduced by 55.1% when compared to PHT/CFC, leading to stable friction profile. The wet friction test in seawater and sunflower oil also demonstrated satisfied wear resistance of PHT/TiO2@CFC, where wear rate decreased by 46.6%. On the other hand, mild degradation solution might effectively recycle CF from PHT/TiO2@CFC composite without damage to properties. In sum, the proposed alternative method for multiscale modification of CF surfaces looks promising for manufacturing of advanced recyclable CFRPs for tribological applications.