The effect of silica nanoparticles, thermal stability, and modeling of the curing kinetics of epoxy/silica nanocomposite

A nanocomposite was synthesized using silica nanoparticles (SN) and Epoxy Vinyl Ester Resin (VE671). Nanoparticles were dispersed in the mixture by ultrasonic equipment to prevent the agglomeration. Transmission electron microscopy was used to investigate the dispersion of the SN in the mixture. Non-isothermal differential scanning calorimetry technique was used to study the cure kinetics of VE671 resin with and without adding SN. The activation energy (Ea) was determined using Kissinger and Ozawa equations. The Ea values of curing for VE671/4 wt% SN system showed a decrease with respect to the neat resin. It means that there is a catalytic effect of SN in the cure reaction. The dynamic curing process was modeled to predict the degree of cure and cure rate of resin using the Sun method. In this method, the results showed a good agreement between the model and the experimental data for different heating rates. Thermal degradation of nanocomposite using thermogravimetric analysis technique was studied. The char yields increased with the addition of 4 wt% of SN to the epoxy resin and improved the polymer flame retardancy and thermal resistance at high temperatures.