Investigation on the mechanical and fracture properties of lightweight pumice epoxy composites.

Pumice, which is prevalent in Ethiopia, is formed naturally during the quick cooling and solidifying of molten lava. Pumice is a naturally occurring mineral that, due to its high thermal resistance and lightweightness, can be an excellent candidate for reinforcing material for polymers. The present study investigates epoxy‐based composites reinforced with pumice particles by varying the pumice content (0, 10, 20, and 30 vol%). The densities of all composites reduce in comparison with neat epoxy as the volume proportion of pumice increases credited to the low density pumice particles. Tensile stress–strain curves depict neat epoxy with higher deformation than other pumice particulate‐filled composites in the linear elastic area followed by rapid brittle failure. Tensile modulus of all the composites increases in the range of 13%–67% in comparison with neat epoxy. The compressive characteristics of composites are greatly improved by the addition of pumice. Compressive moduli and specific compressive moduli of all composites increase with increasing volume fraction of pumice by 54%–58% and 65%–93%, respectively, in comparison with neat epoxy. The fracture toughness of P‐10, P‐20, and P‐30 composites improved by 18%, 54%, and 59%, respectively, as compared with neat epoxy mainly attributed to the foam‐like structure of pumice particles. SEM micrographs are used to analyze the morphology of compression‐tested specimens. Property mapping highlights the advantages of utilizing composites from present work over numerous syntactic foams. [ABSTRACT FROM AUTHOR]