No abstract

Poly(ethylene terephthalate) (PET) nanocomposites reinforced with multiwall carbon nanotubes (MWCNTs) were prepared through melt compounding in a twin-screw extruder. The presence of MWCNTs, which acted as good nucleating agents, enhanced the crystallization of PET through heterogeneous nucleation. The incorporation of a small quantity of MWCNTs improved the thermal stability of the PET/MWCNT nanocomposites. The mechanical properties of the PET/MWCNT nanocomposites increased with even a small quantity of MWCNTs. There was a significant dependence of the rheological properties of the PET/ MWCNT nanocomposites on the MWCNT content. The MWCNT loading increased the shear-thinning nature of the polymer-nanocomposite melt. The storage modulus and loss modulus of the PET/MWCNT nanocomposites increased with increasing frequency, and this increment effect was more pronounced at lower frequencies. At higher MWCNT contents, the dominant nanotube-nanotube interactions led to the formation of interconnected or networklike structures of MWCNTs in the PET/MWCNT nanocomposites.

Polymer nanocomposites based on poly (ethylene 2,6-naphthalate) (PEN) and carbon nanotubes (CNTs) were prepared by direct melt blending with a twin-screw extruder. Dynamic thermogravimetric analysis was conducted on the PEN/CNT nanocomposites to clarify the effect of CNTs on the thermal decomposition behavior of the polymer nanocomposites. The thermal decomposition kinetics of the PEN/CNT nanocomposites was strongly dependent on the CNT content, the heating rate, and the gas atmosphere. On the basis of the thermal decomposition kinetic analysis, the variation of the activation energy for thermal decomposition revealed that a very small quantity of CNTs substantially improved the thermal stability and thermal decomposition of the PEN/ CNT nanocomposites. Morphological observations demonstrated the formation of interconnected or network-like structures of CNTs in the PEN matrix. The unique character of the CNTs introduced into the PEN matrix, such as the physical barrier effect of CNTs during thermal decomposition and the formation of interconnected or networklike structures of CNTs, resulted in the enhancement of the thermal stability of the PEN/CNT nanocomposites. V