Improving tensile properties of glass fiber-reinforced epoxy resin composites based on enhanced multiphase structure: The modification of resin systems and glass fibers

Glass fiber-reinforced polymer (GFRP) composites have been widely used as reinforced materials in marine engineering due to their good corrosion resistance and economic benefits. However, the mechanical properties of GFRP are lower than that of composites reinforced by carbon and aramid fibers etc. Methods to improve the mechanical properties of GFRP received ongoing attention. GFRP have various mechanical properties due to the characteristics of its multiple phases. This study developed an optimized processing method based on multiphase structures for GFRP composites, significantly enhancing the tensile properties of GFRP laminates. The modified GFRP can be produced efficiently by this method to meet more utilization situations in marine engineering. The influence of curing agents, silane coupling agents (SCA)-treated glass fibers (GFs), and nanomaterials on GFRP's tensile properties was investigated. The findings reveal a 10.64 % increase in the characteristic load of GF bundles due to the improved bonding between fibers by SCA. Besides, the contact angle between SCA-treated GFs and epoxy resin shows a significant reduction (26.69 %). Variations in ply thickness and resin system distinctly influence the tensile properties and failure modes of GFRP laminates. Laminates with 4-ply GF fabrics facilitate more effective load transfer across the matrix-fiber boundary, yielding optimal tensile properties for GFRP. Epoxy/phenolic amine resin system with more reactive functional groups (-OH) enhances the fiber-resin bonding, further improving the tensile properties of GFRP. The enhancement mechanism of the multiphase structure in GFRP was elucidated by microscale characterization, indicating that the multiphase structures in GFRP, enhanced by SCA, nanomaterials, and functional curing agents, significantly improve its tensile properties.