Unveiling the temperature-dependent mechanisms of viscoelasticity of sand-enhanced epoxy

Abstract

The viscoelastic behavior of epoxy is critical for its engineering performance and applications. This work focused on the improvement of its viscoelastic performance by using natural sand particles as fillers. Experiments were carried out to investigate the static and dynamic viscoelastic properties of epoxy with various sand particle contents. Static mechanical tests demonstrated an increase in the elastic modulus, albeit at the cost of reduced strength at a higher sand content due to stress concentrations. Dynamic tests indicated substantially improved storage modulus and damping of epoxy after being filled with sand particles. Moreover, the glass transition temperature of epoxy showed a substantial rise upon the addition of sand particles, signifying an augmentation in its heat resistance. Static viscoelastic characterization revealed an elevation in both room- and high-temperature relaxation moduli upon incorporating sand. By applying time–temperature superposition principles, long-term relaxation curves were obtained, which could provide a reference for engineering design. These viscoelastic investigations offer insights into the underpinning mechanisms governing the performance of sand-reinforced epoxy. This enables the rational design of sand-particle-reinforced epoxy for customized durability, heat resistance and vibration damping.