Effects of Aging Temperature and Time on Glass Fiber Reinforced Resin Composites Incorporating Inorganic Filler

Glass fiber reinforced unsaturated polyester resin matrix composites (GFIRPs) are widely used in kinds of fields such as road engineering and construction engineering due to their excellent properties. However, the mechanism of the temperature effect on their performance is still unclear. This study systematically investigates the effects of aging temperature and time on the mechanical properties, thermal stability, and microstructure of GFIRP using bending and compression tests, FTIR, and SEM. In the low‐temperature range of 40°C to 80°C, the curing of the resin is enhanced, and the bonding strength between components increases, leading to improved mechanical properties of GFIRP. Aging at 80°C resulted in the mechanical properties reaching their maximum, representing an approximate 55% improvement over the baseline (40°C). However, when the temperature exceeds 80°C, the mechanical properties begin to decline; at 180°C, the flexural strength and compressive strength decreased by approximately 76% and 80% relative to the baseline, respectively. The study on aging time shows that short‐term aging at 120°C (up to 10 days) can enhance mechanical properties by increasing the resin's curing degree and interfacial bonding strength, whereas prolonged aging (beyond 10 days) results in thermal oxidation, micro‐damage, and performance degradation. The findings suggest that low temperatures such as 60°C and 80°C can improve the performance of GFIRP in the short term, while long‐term exposure to high temperatures can cause irreversible structural damage. This provides a scientific basis for optimizing the preparation process of GFIRP, enhancing its durability, and expanding its applications.