Electrical properties of carbon black filled HDPE composites

The electrically conductive CB/HDPE composites were prepared by melt compounding method. These CB/HDPE composites present positive temperature coefficient (PTC) phenomenon in which the resistivity was sharply increased near the crystalline melting temperature and negative temperature coefficient(NTC) phenomenon in which the resistivity was sharply decreased above the crystalline melting temperature. The electrical conductivity and PTC intensity of composites were affected by preparation conditions such as heat treatments, stretchings, and thermal shrinkage etc., resulting from the changes of the degree of crystallinity and crystal orientation of composite films. It was also found that the crosslinking reaction of silane treated composite induced the disappearance of the NTC phenomenon and the improved reproducibility of PTC phenomenon.