Electrical and Thermal Properties of PET/Polyetherimide/Multiwalled Carbon Nanotube Nanocomposites

Nanocomposites of blends of poly(ethylene terephthalate) (PET) and polyetherimide (PEI) with multiwalled carbon nanotube (CNT) were studied. The percolation threshold value for electrical conductivity of PET/PEI/CNT nano composites was observed to be in the range of 0.25 wt% or 0.5 wt%, depending on the content of PET and PEI in the nanocomposites. Especially, nanocomposites with PEI-rich composition showed better electrical conductivity than PET rich nanocomposites due to the good dispersion of CNT. Electrical conductivity of the nanocomposite was increased by the heat treatment. Annealed nanocomposite at 130 degrees C showed better electrical conductivity than quenched nano composite or annealed one at 215 degrees C. DSC results showed that the heat treatment conditions altered the phase separation and crystallization behavior of PET/PEI blends. SAXS analysis gave similar results. The increased electrical conductivity by heat treatment seemed to be brought about by such factors including phase separation.