Optimization of Curing Temperature for Epoxy/SiO2/Glass Fiber Composite: Dual Enhancement of Mechanical Strength and Thermal Stability for Thin-Walled Pressure Vessels

Abstract

The development of advanced composite materials for thin-walled pressure vessels demands a balance between mechanical strength and thermal insulation. In this study, a novel three-phase composite system comprising epoxy resin, silica (SiO2) micro-particles, and glass fiber reinforcement was fabricated and characterized for potential application in high-performance thin vessel structures. Specimens were cured at varying temperatures (60°C to 160°C) to systematically investigate the influence of curing conditions on the structural and thermal properties. Comprehensive material characterization, including Fourier transform infrared (FTIR) spectroscopy and x-ray diffraction (XRD) analysis, confirmed the successful integration of silica and glass fiber within the amorphous epoxy matrix. Thermogravimetric analysis (TGA) revealed a two-stage degradation process, with maximum thermal stability observed at 120°C curing temperature. Specific heat capacity (Cp) and measurements indicated decreasing trends with increasing curing temperature, enhancing thermal insulation. Mechanical testing demonstrated that hoop strength (SH) and burst pressure (Pb) improved significantly with curing temperatures up to 140°C, following third-degree polynomial relationships. Notably, the composite cured at 120°C exhibited the highest combination of hoop strength (341.3 ± 6.5 MPa), burst pressure (16.66 ± 0.3 MPa), Cp (2.33 J/g·K), thermal conductivity (0.198 W/m·K) and Factor of Safety (1.39 ± 0.024), while maintaining superior thermal resistance. Theoretical predictions showed strong agreement with experimental results across all evaluations. Overall, the optimized epoxy/SiO2/glass fiber composites offer a lightweight, thermally stable, and mechanically robust alternative to traditional metallic vessels, highlighting their potential for use in chemical, oil, and pharmaceutical industries requiring durable thin-walled pressure containment solutions.