Constructing a "brick and mortar" structure to synchronously strengthen the mechanical and tribological properties of fabric laminated composites by isocyanate functionalized carbon fiber powders

Fabric laminated composites with excellent mechanical strength and brake stability are now developed as promising wet friction materials. However, facing the serious challenge of persistent operation under harsh conditions, abrasive resistance and interlaminar bonding properties of laminated composites require further improvement urgently. Herein, the methylene diphenyl diisocyanate (MDI) was chemically grafted onto the carbon fiber powder (CFP) surface via oil bath for surface functionalization. Subsequently, fabric laminated composites modified with functionalized CFP (CFP-MDI) were fabricated by sedimentation to construct a "brick and mortar" structure. As a result, the comprehensive performance of laminated composites presented an effective promotion with the introduction of CFP-MDI as mortar. In particular, benefiting from the conspicuous synergistic effect between CFP and MDI, the interlaminar shear strength of modified laminated composites was increased by 17.93%, and the wear rate decreased by 38.18% from 7.91×10^-14 m³(N·m)^-1 to 4.89×10^-14 m³(N·m)^-1, demonstrating excellent ability to efficiently suppress crack and local damage propagation. This work provides a new strategy to achieve the integrated construction of toughening interlamination and wear-resistant coating, which is conducive to the large-scale application of fabric laminated composites in the friction transmission braking field.