Thermal degradation kinetics of PET/SWCNTs nanocomposites prepared by the in situ polymerization

The decomposition and thermal behavior of poly(ethylene terephthalate) (PET)/carbon nanotubes (CNTs) nanocomposites were studied using thermogravimetric (TG) analysis in air atmosphere. A series of PET/single-walled CNTs (SWCNTs) materials of varying nanoparticles concentration were prepared using the in situ polymerization technique. Transmission electron microscopy and scanning electron microscopy micrographs verified that the dispersion of the SWCNTs in the PET matrix was homogeneous, while some relatively small aggregates co-existed at higher filler concentration. Two-stage decomposition was observed in the experiments. During first stage, strong chemical bonds are broken, i.e., aliphatic bonds and benzyl ring containing molecules decompose into small molecules in the gaseous phase. During second stage, when temperature is higher, the remaining nanotubes along with the residues of the first stage are burned. Kissinger and Coats–Redfern (5, 10, 20, 50 K min^?1) methods were applied to TG data to obtain kinetic parameters (activation energy, Arrhenius constant at 600 K and A factor) and Criado method to kinetics model analysis. In this kinetic model, energy activation is increasing with the increase of nanotubes concentration.