Preparation of multiaxial glass fiber/epoxy prepreg and its mechanical properties in composites

Abstract

This study investigates the mechanical properties of composites made from biaxial warp-knitted glass fiber/epoxy prepregs (BW-GF/EP) in comparison to plain woven glass fiber/epoxy prepregs (PW-GF/EP). The BW-GF/EP composites demonstrated superior tensile strength, with an increase of 9.5%, and bending strength, with an increase of 12.2%, compared to the PW-GF/EP composites. Despite having a lower tensile modulus, the BW-GF/EP composites exhibited 8.7% higher interlaminar shear strength. Dynamic mechanical analysis showed that both materials had similar storage and loss moduli at lower temperatures, with PW-GF/EP performing better at higher temperatures. Microscopy revealed that failure in PW-GF/EP occurred at weave intersections, while BW-GF/EP composites showed fiber rupture and delamination. The findings highlight the advantages of using biaxial warp-knitted fabrics for improved composite performance. Highlights: Developed biaxial warp-knitted fabric prepregs to replace liquid molding techniques. Improved interlaminar shear strength, reducing delamination risks in composites. Achieved higher tensile and bending strength compared to plain weave composites. Enhanced resin impregnation and molding efficiency with biaxial warp-knitted fabrics. Reduced environmental impact and costs by avoiding VOCs and minimizing waste.