Impact of different nanoparticles on the thermal degradation kinetics of phenolic resin nanocomposites

The effect of different contents of nano-fillers: carbon black (CB), bentonites [original (Bent) and modified with phosphonium salt (B-TBHP)] and commercial modified montmorillonite (C30B) on the thermal degradation of phenolic resin was studied by thermogravimetric analysis (TG). The obtained results strongly suggest that CB was the most effective filler in improving the thermal stability of the resol-type phenolic matrix. The previous results were associated with the thermal stability of each filler but also with the compatibility between the matrix and the filler and the effect of filler incorporation on the cross-linking degree of the neat matrix. The profile of the apparent activation energy with the conversion of the thermal degradation process for the resol and the nanocomposites was obtained using three isoconversional methods: Friedman, KAS and Vyazovkin. The curves were correlated with the degradation steps of the phenolic resin observed by TG, showing a similar degradation mechanism for all the systems. By means of the method of invariant kinetic parameters, it was possible to estimate the preexponential factor and the activation energy to describe the degradation process of the resol and the nanocomposites in the thermal fragmentation zone, between 350 and 600 A degrees C. It was determined that the Sestak-Berggren model was the one that best describes the thermal degradation experimental data. Then, a comparison between the experimentally obtained and the simulated differential degradation curves shows that the resulting model was certainly accurate to predict the thermal degradation process of the resol and the nanocomposites.