UV ageing of epoxy resin-based glass fiber-reinforced polymer composites incorporating with various curing agents

Improving the mechanical and durability-related properties of the glass fiber-reinforced polymer (GFRP) composites exposed to harsh maritime environments are an ongoing concern. This study comprehensively explored the effect of modified resin systems on the tensile properties of laminates in high ultraviolet (UV) and humidity environments. The UV aging behaviors of resin and GFRP laminates with different curing agents were evaluated, including the tensile properties and colorimetry. The dynamic mechanical properties, Fourier Transform Infrared Spectroscopy (FTIR) analysis and microstructural observations of the GFRP composites were evaluated to further analyze the deterioration mechanism. The results showed that the epoxy resin system with dense chemical structures demonstrated a greater ultimate tensile strength, which can be attributable to its rigid elements and small molecular spacing between reactive functional groups. Laminates comprising 4-ply prepregs facilitated a more effective load transfer across the matrix-fiber boundary, yielding optimal tensile properties of GFRP composites. The yellowing degree of resin incorporating phenolic amine curing agent increased rapidly within 7 d UV exposure. Deeper color of resin matrix reduced UV damage to upper fibers. The use of resin matrix with dense chemical structures and polar functional groups (-OH) can improve the tensile properties of GFRP and keep it at high ultimate tensile strength and toughness after 90 d UV exposure.