A novel wear‐resistant diamine type polybenzoxazine composites reinforced by modified poly(p‐phenylene supported benzodioxazole) (<scp>PBO)</scp> fiber and polytetrafluoroethylene (<scp>PTFE)</scp>

Abstract High brittleness and poor wear resistance of typical diamine type polybenzoxazine of poly(PH‐ddm) have become important issues affecting its tribological application. Herein, the modified poly(p‐phenylene supported benzodioxazole) (PBO) fiber and thermoplastic of polytetrafluoroethylene (PTFE) were selected to perfect the mechanical and tribological performance of poly(PH‐ddm). The PBO fiber was modified by Ag nanoparticles via PDA as an active transition layer (PBO‐PDA‐Ag), which demonstrated increased surface roughness and active sites, and good thermal stability. Due to the high strength and modulus, the addition of PBO‐PDA‐Ag increased the tensile strength of poly(PH‐ddm) composites from 30.9 to 40.75 MPa, as its content increased from 5 to 20 wt%. Furthermore, as the content of PBO‐PDA‐Ag and PTFE was 15 and 5 wt%, the tensile strength of the corresponding composites was improved to 36.8 MPa, and its friction coefficient and wear rate were decreased by 65% and 93.8% compared to pure poly(PH‐ddm). The enhancing effect of the modified PBO fiber could make poly(PH‐ddm) resistant to stress, thereby avoiding serious wear. Meanwhile, the PTFE would preferentially form a transfer film at the sliding surface as the friction progressed, and Ag nanoparticles on the surface of PBO would gradually be exposed to the worn surface and produce a hybrid lubricating film. Overall, the findings of the present study might promote the development of novel polybenzoxazine composites with enhanced tribological properties. Highlights Ag nanoparticle was in situ grown on PBO fiber surface using PDA as active platform. Both PBO‐PDA‐Ag and PTFE improved the tensile strength of poly(PH‐ddm). The wear resistance of poly(PH‐ddm) was improved by 15 wt% PBO‐PDA‐Ag and 5 wt%PTFE. The synergistic lubricating mechanism of PBO‐PDA‐Ag and PTFE was explored. This work might promote the development of wear‐resistant polybenzoxazine composites.