Hierarchical reinforcement approach to laminated CFRP composites: electrospinning polyvinylidene fluoride fiber on carbon fabric and introducing spun zirconia fiber into the interlayer

This study employed a hierarchical reinforcement strategy to fabricate a laminated carbon fiber-reinforced polymer (CFRP) composites with the various dimensions of polyvinylidene fluoride fiber (PFF) and zirconia fiber (ZF). A disordered PFF veil with diameter of several hundred nanometers to micron was constructed via directly electrospinning onto the carbon fiber (CF) fabric, while spun ZF with diameter of about 8 micron was further introduced into the interlayer. 3 PB tests demonstrated a significant enhancement in the mechanical properties of the composites, the specimen with 0.24 g/m2 PFF and 0.16 g/m2 ZF achieved a greatest flexural strength of 736.58 MPa, a 25.6% increment over the unreinforced group (586.57 MPa). The hierarchical synergistic effect of PFF and ZF regulated the damage evolution process of composites under bending load. The PFF veil improved the interfacial bonding strength through fiber bridging and plastic deformation, while ZF improved the strength of the resin through fiber bridging and fiber pull-out. Together, they facilitated more uniform stress distribution and energy dissipation, thereby improving the flexural strength and damage resistance of composites. This approach provided a new strategy for designing high-strength CFRP composites.