Synergistic Effect of Nano-silica and Micro-silica Fillers on the Rheological Properties of Epoxy Resin

This study aims to improve nanofiller dispersion in epoxy resins by using the electrostatic disperser (ED) as well as to reduce the cost, by using combination of micro- and nanofillers. The ED method aids in homogenized mixing of nanofillers in epoxy resin, due to its jet elongation and shearing effect on polymer mix. In this context, two concentrations (7.5 wt % and 5 wt %) of nano-silica are used and their rheological properties are tested, before and after the addition of 50 wt% micro-silica. A plausible mechanism of filler dispersion is explained for ED and high shear (HS) methods. It is observed that electrostatic dispersion method aids in network formation of nano-silica, unlike high shear method wherein clusters of nano-silica are formed. Hence ED method aids in reducing the viscosity values with the addition of micro-silica, which is helpful in product molding process. The flexural strength and heat deflection temperature lie in same range for both composites prepared using ED and HS methods.