Impact of shear mixing time of epoxy-silica nanocomposites on its electrical and mechanical properties

The shear mixing time was varied to study its influence on electrical and mechanical behaviour of epoxy-silica nanocomposites. Epoxy resin along with 1 wt.% of silica nanofillers were subjected to shear mixing at different time spans. Water droplet-initiated corona inception voltage (CIV) was observed to increase with the shear mixing time, under AC and DC voltages. A marginal increase in contact angle a function of shear mixing time was noticed. The CIV due to water droplet and the contact angle has shown a direct correlation. The epoxy-silica nanocomposite sample fabricated with 7 h of shear mixing time has led to 46.68% increment in CIV under AC voltage and 24.81% increment in contact angle compared to base epoxy resin. The ultimate tensile strength (UTS) and the Young's modulus of nanocomposites have increased with shear mixing time and at 7 h of shear mixing time has shown increase in ultimate tensile strength and Young's modulus of 45.78% and 43.77%, respectively, as compared to base epoxy resin. The strain versus time plot obtained from the digital image correlation (DIC) studies has shown that maximum strain occurs at a time period before breakdown has increased with shear mixing time up to 7 h. The time at which the maximum strain occurs has increased to 91.49% before the breakdown of epoxy-silica nanocomposite sample which was prepared with 7 h of shear mixing time as compared to base epoxy resin.