Impact of carbon nanotubes addition on electrical, thermal, morphological, and tensile properties of poly (ethylene terephthalate)

Abstract

In this study, multi-walled carbon nanotubes (MWCNTs) were incorporated into poly (ethylene terephthalate) (PET) matrix in their as-received (A-MWCNTs) and treated (T-MWCNTs) forms. Melt-compounding method was used for the preparation of these carbon nanotubes (CNTs)-reinforced PET composites. The electrical conductivity, thermal stability, morphological, and tensile properties were investigated. For testing and characterization, impedance spectroscopy, thermo-gravimetric analysis, scanning electron microscopy, transmission electron microscopy, Fourier-transform infrared spectroscopy and tensile testing were utilized. The results demonstrates that an incorporation of ~0.25 wt% A-MWCNTs, an electrically conductive polymer nanocomposite (~0.2 S/m), was formed with a low percolation threshold (~0.33 wt%). In contrast, at the same loading of T-MWCNTs or even up 2 wt% did not yield conductive polymer. Presumably, such behavior is attributed to the acid treatment that disrupted the inherent electrical conductivity of the CNTs and also reduced their aspect ratio. Nevertheless, T-MWCNTs showed a better dispersion and distribution into the PET matrix than that of A-MWCNTs counterpart. Moreover, an improved tensile behavior was observed for T-MWCNTs incorporated composites than that of A-MWCNTs counterpart. Improved thermal stability was observed for PET/A-MWCNTs in both the air and nitrogen atmospheres. Whereas, PET/T-MWCNTs exhibited the highest thermal stability in all samples in nitrogen atmosphere. However, poor thermal response was seen in air atmosphere.