Effect of Reinforcement of Sustainable β-CaSiO3 Nanoparticles in Bio-Based Epoxy Resin System

The beta-CaSiO3 nanoparticles (NPs) were prepared using calcium carbonate from egg shells and silica as precursors. These NPs were incorporated (1-4 wt %) into bio-based epoxy resin to fabricate nanocomposites. Thermal and mechanical tests were carried out on these composites. The results of dynamic mechanical analysis showed significant improvement in the storage modulus of 1 and 2 wt % composites. The thermomechanical analysis data revealed similar to 19 and 20% of reduction in coefficient of thermal expansion for 1 wt % of CaSiO3 before and after glass transition as compared to the neat epoxy system. Thermogravimetric analysis results also showed delayed thermal degradation of the composites by significant amounts (17-35 degrees C) for 5% of decomposition, a proportional increase in residues corresponding to the loading concentrations. The flexure tests showed significant improvements in strength (17-36%), modulus (5-33%), and toughness for 1-4 wt % of reinforcement of beta-CaSiO3 NPs. Theoretical calculations of the reinforcement effect on the flexure modulus of the composites agree well with the experimental values. The scanning electron micrograph of the fractured surfaces revealed better interfacial interactions in the composites and enhancements in crack path deflections over the neat specimen. (C) 2014 Wiley Periodicals, Inc.