Enhancing thermo‐mechanical properties of epoxy using flake‐like micro expanded perlite particles

Abstract The physical and thermo‐mechanical properties of polymer matrix composites can be improved by incorporating different organic and inorganic filler materials. In this work, a novel flake‐like filler material, expanded perlite powder, was used to fabricate epoxy composites, and the effects of filler contents (0, 0.5, 1, 2, 3, 4, and 5 wt.%) on the physical and thermo‐mechanical properties of epoxy were investigated. The composites were characterized by their density, porosity, tensile properties, flexural properties, hardness, thermal conductivity, thermal stability, and burning rate. The scanning electron microscope (SEM) image of the fracture surface showed evidence of good bonding and dispersion of particles for low perlite content, but agglomeration and large voids were found at high perlite content. The tensile strength, tensile modulus, flexural strength, flexural modulus, shore D hardness, and Vickers hardness were enhanced significantly by 58.82%, 101.00%, 38.75%, 42.38%, 19.10%, and 38.40%, respectively, at an optimum perlite content of 2 wt.% compared to those for the pure epoxy. The properties deteriorated beyond the optimal content of perlite. The thermal conductivity showed an enhancement of 124% compared to the pure epoxy at a perlite content of 3 wt.%, and the thermal stability was improved with the addition of perlite powders in the epoxy. The reduction in the burning rate was found to be insignificant with the addition of perlite powder. The synergistic effects of perlite powder in the epoxy matrix show great potential for developing high‐performance composite materials. Highlights Physical and thermo‐mechanical behavior of epoxy with perlite powder studied. Perlite addition enhances tensile, flexural, and hardness properties. Transition from ductile to brittle failure with increased perlite is seen. Thermal conductivity is increased by 124% at 3 wt.% perlite, then decreased. Perlite incorporation reduced the burning rate and improved thermal stability.