The synergistic impacts of hybrid nanofillers of graphene nanoplatelets/carbon nanotubes on curing behavior of an epoxy‐vinyl ester interpenetrating polymer network nanocomposite coating

Abstract

AbstractThis study investigated the synergistic effects of hybrid graphene nanoplatelet (GnP)/multi walled carbon nanotube (MWCNT) nanofillers at various loadings on the kinetics of curing of the epoxy (EP)/vinyl ester (VE) interpenetrating polymer network (IPN) system, with a mass ratio of 1:1. Fourier transform infrared spectroscopy (FTIR), dynamic mechanical thermal analyzer (DMTA) and differential scanning calorimetry (DSC) were used to monitor the interpenetration process of EP and VE and likely interactions between the components of the different resin systems in IPN. The curing behavior of all prepared samples under non‐isothermal conditions was studied using DSC at four heating rates. Two different isoconversional approaches were applied to evaluate the reaction kinetics, that is, the Friedman and the advanced Vyazovkin methods. The obtained activation energy curves for all samples revealed a complex curing behavior involving three stages; early IPN stage, IPN growth stage, and late IPN stage. Then, the activation energy values for each reaction step were determined based on the Friedman method. The presence of GnP/MWCNT nanoparticles showed no catalytic effect on the reaction of VE with methyl ethyl ketone peroxide (MEKP). In contrast, incorporating GnP/MWCNT nanoparticles significantly decreases the activation energy values of the reaction of ring opening of epoxides with methyl tetrahydrophthalic anhydride (MTHPA) 1‐methyl imidazole (‐Mi) and the reaction of esterification of the hydroxyl groups of VE with MTHPA.Highlights Model‐free methods used to curing study of epoxy‐vinyl ester IPN nanocomposites FTIR, DSC and DMTA used for evaluation IPN formation of EP/VE It showed that the improvement of dispersion and compatibility by using of GnP/MWCNT hybrid Frideman and Vyazovkin methods used to calculate Ea of nanocomposites DSC thermograms were deconvoluted into three individual peaks.