Durability of vacuum infused GFRP composites exposed to natural and artificial accelerated weathering

The available literature provides limited information on how different weathering environments influence the durability of fibre reinforced polymer (FRP) composites, especially for thick vacuum infused laminates. Against this backdrop, this paper presents the results of an experimental study on the effects of natural and artificial accelerated weathering on 6.5 mm thick (nominal thickness) vacuum infused glass-FRP (GFRP) composites, produced with unsaturated isophthalic polyester and vinyl ester resins. Natural exposure was conducted at four different outdoor locations in Portugal, for periods of 12 and 24 months. The composites were also subjected to artificial accelerated weathering in a QUV chamber for up to 10,000 h. After each exposure period, aesthetic changes (visual inspection, colour and gloss), thermomechanical behaviour (Dynamic Mechanical Analysis and Glass Transition Temperature, T g ) and mechanical properties (tension, compression, flexure, in-plane shear and interlaminar shear) were evaluated. All weathering environments caused pronounced colour changes and fibre blooming. Across the different natural ageing environments, the maximum degradation ranged in 1–5 °C in T g , 3–4% in tensile strength, 4–9% in compressive strength, 9–14% in flexural strength, and 1–2% in in-plane (IP) shear strength, while interlaminar shear strength (ILSS) suffered no reduction. Under artificial accelerated weathering, the reduction in flexural strength varied between 6% and 7%, while ILSS presented no reduction as in natural weathering. No relevant differences were observed in the weathering performance of the two resin systems. The reductions in mechanical properties remained well within the 50-year conversion factor for outdoor exposure provided in CEN/TS 19101:2022. • Durability of vacuum infused GFRP composites under natural and artificial weathering. • Significant impact on the aesthetic properties of GFRP composites. • Minimal reduction of T g under natural and artificial weathering. • Mechanical property variations mostly remained within experimental scatter. • Retention values in agreement with conversion factor in CEN/TS 19101:2022.