Formulating Epoxy Resin for General Aviation and Predicting Rheological and Curing Properties

The room-temperature curing system, comprising epoxy resin L285 and H287 curing agent, has a wide range of applications in general aviation. The mass ratio of epoxy resin to curing agent significantly influences its performance. In this study, the effects of deviation from theoretical mass ratios (10:3, 10:4, 10:5, and 10:6) on the rheological, cross-link density, and performance were systematically investigated using viscosity tests, mechanical tests, scanning electron microscopy analysis, dynamic mechanical analysis, thermogravimetric analysis, and moisture absorption analysis. The results showed that a 10:4 ratio yielded optimal performance in the cured epoxy material, with a tensile strength of 73.03 MPa, bending strength of 131.16 MPa, thermal stability ([Formula: see text]), heat resistance ([Formula: see text]), and moisture absorption of 0.57%. The 10:3 ratio exhibited a slower viscosity increase, extending the processing window to 300 min. However, its lower cross-link density ([Formula: see text]) resulted in reductions of 17.8% in tensile strength and 29.7% in flexural strength compared to the 10:4 benchmark. While the 10:5 and 10:6 ratios also showed declines in mechanical performance (15.1% and 19.2% for tensile strength and 14.5% and 29.1% for flexural strength, respectively), the 10:5 formulation achieved the highest [Formula: see text] peak temperature of [Formula: see text]. The backpropagation neural network accurately predicted performance parameters, aligning with experimental data. This study provides scientific guidance for aerospace composite design and application.