In situ synthesis of polyurethane/aramid nanofiber composites with silane‐coupling‐agent‐functionalized interfaces: Enhancing wear resistance and mechanical properties via interfacial interactions and silica nanonetwork formation

Abstract Aramid nanofibers (ANFs) were widely used in the resin matrix due to their excellent heat resistance, wear resistance, and dimensional stability. ANF and polyurethane (PU) had similar molecular structures, allowing for hydrogen bonding interactions between them. To achieve good dispersion of ANF in the PU matrix, inspired by natural spider silk, silane coupling agents were utilized to modify the surface of the aramid nanofibers; a network shell of silanol and amino groups was formed in situ on the surface of the ANF. This method achieved good dispersion of ANF in PU, significantly improving tensile strength and wear resistance. By in situ synthesizing ANF/PU composites, the amine and hydroxyl groups on the modified ANF surface could react with free isocyanate groups; the synergistic effect of hydrogen bonds and covalent bonds provided strong interfacial interactions. The interfacial interaction between the filler and the matrix was enhanced; adding 0.1% TANF resulted in the composite material exhibiting excellent mechanical properties (35 MPa, 500%). The addition of 0.4% ANF reduced the friction coefficient and improved wear resistance, with the wear resistance of the PU/ANF composites showing a significant advantage of 58% over pure PU composites, laying the foundation for the development of multifunctional composites with broad application potential. Highlights In situ synthesis of silicon nanonetworks enhances interfacial bonding in PU/ANF composites. Reorientation of polyurethane molecular chains enhances the mechanical performance of composites. Significant mechanical enhancement achieved: 35 MPa tensile strength, 500% elongation at break, wear resistance improving by 58%.