Improvement in thermal, mechanical and water resistance properties of epoxy/glass particulate composites

Abstract

Glass particulate reinforced epoxy matrix composites containing 0 to 32 vol% glass particulate were prepared by mechanical mixing followed by hot pressing. For this, lead borosilicate glass of composition 75PbO, 7B2O3, 14SiO2, 3Al2O3, and 1P2O3 (by wt%) was prepared by melting the requisite ingredient at 900 °C and quenching the melt to produce glass frit. Prepared composites were characterized by various characterization techniques. Scanning electron microscope showed good dispersion of glass particulates in the matrix. However, some porosity was found at higher glass content. Vickers hardness increased by 4 folds for 32 vol% composite. It correlates well a modified rule of mixtures with strengthening efficiency parameter (β) equal to 0.25. The coefficient of thermal expansion (CTE) decreased by 40 % for 32 vol% composite. Experimental CTE is slightly lower than that of theoretical CTE due to the good adhesion between the epoxy and the glass particulates. The moisture absorption of the composites measured at 95 °C follows Fickian diffusion. The parabolic rate constant decreased from 0.20 to 0.022 cm−2 h−1/2 as the glass content increased from 0 to 32 vol%. The 2 h boiling water test showed that the moisture absorption rate of composite decreased by 8 folds compared to pure epoxy.