Dynamic cure kinetics of epoxy/TiO2/MWCNT hybrid nanocomposites

Abstract

The effect of multi-walled carbon nanotubes (MWCNTs) on cure kinetic parameters of the epoxy/amine/TiO2 (1 wt%) resin system was studied dynamically at four heating rates using DTA. The presence of MWCNT in various amounts (0.1, 0.2, 0.4 and 0.6 wt%) neither retarded nor accelerated the cure reaction of the epoxy/amine/TiO2 system in a considerable extent. Addition of MWCNTs increased the extent of cure of the corresponding nanocomposites, especially at higher contents up to 0.4 wt% MWCNT filled composite. However, increasing the MWCNT content to 0.6 wt% adversely affected the extent of cure due to nanoparticle agglomeration. The fracture surface morphology of the nanocomposites revealed that the cracks deviated on reaching the MWCNTs, while propagating in the polymer matrix. Fractional extent of conversion (α) was calculated using genetic algorithm. Flynn–Wall–Ozawa and Kissinger methods were used to analyze the kinetic parameters. The presence of MWCNTs did not affect the autocatalytic cure mechanism of epoxy/amine/TiO2 resin system and also did not cause any considerable barrier effect on the curing process. Activation energy data fitted well in the cubic polynomial regression equations and the changes of Ea with respect to α proved the autocatalytic cure mechanism, being followed by all the MWCNT-containing epoxy-based hybrid nanocomposites.