Abstract: PE-HD/MWCNTs composties and PE-HD/CB composites were prepared by solution blending and ultrasonic dispersion. It was found that PE-HD/MWCNTs composites possessed lower resistivity at room temperature, higher positive temperature coefficient (PTC) intensity, and lower negative temperature coefficient (NTC) effect, when compared with PE-HD/CB composites. The analysis of the whole resistivity-temperature curve of PE-HD/MWCNTs composites illustrated that the PTC effect was resulted from both the diffusion of MWCNTs to crystalline areas and the volume expansion of the matrix; while NTC effct was caused by contacting between MWCNTs due to their thermal motion, rather than the agglomeration of particles.

Key words: resistivity-temperature characteristic, high-density polyethylene, multi-walled carbon nanotubes, carbon black, conductive composite