Effect of Silica Nanoparticles on Activation Energy of Phenol Novolac Epoxy Resin/Unsaturated Polyester at Various Temperatures

In the current study, the activation energy of modified phenol novolac epoxy (PNE) resin with unsaturated polyester (UPS) and silica nanoparticle (SN) at different filler loadings was investigated. In this case, effect of silica nanoparticles as a nano-size filler on the activation energy of PNE/UPS blend was evaluated. For this matter, tetraethylene pentamine (HA-11) which is an amine hardener was used as curing agent. SNs were dispersed in the mixture using ultrasonic equipment to prevent their agglomeration. The curing reaction of epoxy-based resins is exothermic. In this regard, the dynamic curing process was studied using differential scanning calorimetry (DSC) in four different heating rates, including 2, 5, 10 and 15 °C/min. Besides, various methods, including Ozawa, Flynn-Wall, Friedman and Butchart-Denilez were used to determine whether the activation energy of PNE/UPS blend or the best method for calculation of activation energy. Achieved results showed that the addition of SNs to the matrix can increase the activation energy and thus increase the curing time.