Long‐chain branching of polyethylene terephthalate: Rheological/thermal properties of polyethylene terephthalate/carbon nanotube nanocomposite

Abstract Thermal degradation of polyethylene terephthalate (PET)/carbon nanotube (CNT) nanocomposites is a serious issue in the manufacturing process of this nanocomposite that can limit the applications of the nanocomposite. In this study, the effects of two kinds of chain extenders, pyromellitic dianhydride (PMDA) and pentaerythritol (PENTA), on the rheological behavior, thermal characteristics, and crystallinity of the PET were investigated. The results of shear rheology revealed improvement of the storage modulus and complex viscosity, which indicated the recoupling of broken chains, increasing the chain length, and the generation of long branches was the reason for chain extension. Also, differential scanning calorimetry (DSC) results clarified an increase in PET crystallization rate in the presence of CNT and chain extenders. Furthermore, SEM was performed to detect CNT dispersion in the nanocomposite, and four‐probe technique test was utilized to determine the influence of CNT on the electrical properties of PET.