Solvent Absorption Characteristics of Epoxy-Colloidal Silica Nanocomposites

Abstract

The epoxy-colloidal silica nanocomposites were prepared by directly blending a two pack system of Araldite (CY-230) and hardener (HY-951) with colloidal silica. As the colloidal silica powder was considerably fine, the weight percent was kept quite low. The silica content was varied from 1% to 3% by weight of the total matrix. These composites were then characterized for morphology using scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and absorption kinetics in various solvents including distilled water, ethanol, acetone, carbon tetrachloride, and methylethylketone. Absorption kinetics was studied at two temperatures, that is, 30°C and 50°C. The SEM micrographs indicated the uniform distribution at lower concentrations, that is, up to 2% of colloidal silica. TGA results show improved thermal stability and increase in ash content with increase in silica content. Swelling kinetics shows that for most of the solvents the nature of diffusion is non-Fickian and as the silica content increases, deviation from Fickian behavior increases. Moreover, diffusivity decreases with increase in silica content but increases with temperature. Sorption values increases with silica content and also increase with temperature. Various reasons for deviation from Fickian behavior were studied.