Anomalous attenuation of the positive temperature coefficient of resistivity in a carbon-black-filled polymer composite with electrically conductive in situ microfibrils

The positive temperature coefficient of resistivity (PTCR) of in situ microfibrillar carbon black/poly (ethylene terephthalate)/polyethylene composite attenuates dramatically after a sufficient time of isothermal treatment without oxygen above the melting region of polyethylene. The inhomogeneous surface microstructure and the large size of the microfibrils are the key factors controlling PTCR attenuation, through which a model is proposed to explain this anomalous phenomenon. An effective approach is accordingly developed to prepare recyclable semicrystalline thermoplastic based electrically conductive polymer composite with steady conductivity in wide temperature range. (c) 2006 American Institute of Physics.