Investigation on the optimized curing cycle of epoxy resin for enhancing thermal and mechanical properties of glass fiber reinforced plastic applications

Abstract Understanding the thermal and mechanical behavior of epoxy resins under varying curing conditions is critical for optimizing the performance of fiber-reinforced plastics (FRP) in industrial applications. This study investigates the influence of curing temperature and post-curing stages on key epoxy properties, including heat distortion temperature (HDT), glass transition temperature (Tg), and crosslinking density, and evaluates their impact on the performance of glass FRPs (GFRPs). Two epoxy resin systems with distinct Tg were examined using differential scanning calorimetry to asses curing behavior and dynamic mechanical analysis to evaluate HDT, Tg, and crosslinking density. As curing temperature increased, the 1050/1056 epoxy resin system exhibited improvements in HDT, Tg, and crosslinking density (up to 69 °C, 78.3 °C, and 1674.6 mol m −3 respectively) with further enhancements observed after post-curing. Similarly, under the same conditions, the 1800/1805 epoxy resin system demonstrated changed value (up to 97 °C, 108.9 °C, 2287.6 mol m −3 respectively) with further improvements observed after post-curing. These changes in properties were validated through GFRP performance metrics, with tensile strength reaching up to 558.5 MP and shore A hardness up to 92.5 under optimized curing conditions. These findings reveal how curing conditions significantly affect both the thermal and mechanical properties of epoxy and epoxy-based composites, offering valuable insights for tailoring performance in applications such as molds, structural components, and high-precision industrial systems.