Studying the effect of micro- and nano-sized ZnO particles on the curing kinetic of epoxy/polyaminoamide system

The present study investigated curing kinetic of epoxy/polyaminoamide/ZnO implementing isothermal differential scanning calorimetry (DSC) technique. Model free and model fitting methods were used to study the curing reaction kinetic. Isoconversional method results showed that the activation energies (Ea) of pure epoxy/polyaminoamide, epoxy/polyaminoamide/micro-ZnO, and epoxy/polyaminoamide/nano-ZnO systems remained constant in different conversions. Moreover, the model fitting method was used to determine the kinetic triplet, i.e., pre-exponential factor [A], activation energy [Ea], and reaction order [n] by simultaneous processing of all isothermal curing data. Both methods indicated a decrease in activation energy by adding ZnO as well as a decrease in the particle size from micro to nanoscale. This can be attributed to the catalytic effect of ZnO by forming a complex between Zn++ and oxygen of oxirane ring and carboxylate group in epoxy.