Electrically Conductive Rubber with Positive Temperature Coefficient of Resistance from Tire Regenerate

摘要

The possibility of developing conductive rubber based on tire regenerate and conductive carbon black OMCARB CH85 is shown. The vulcanizing characteristics of the regenerates obtained by thermomechanical devulcanization using a curing group and conductive carbon black were studied. It is shown that, after thermomechanical devulcanization, a re-vulcanization due to preservation of sulfide bonds occurs only in the presence of sulfur and vulcanization accelerators. A flocculation effect was found upon the introduction of OMCARB CH85 into the regenerate. It is shown that tensile strength and Shore A hardness are increased with an increase in the content of conductive carbon black in the regenerate. However, owing to insufficient dispersion, the carbon black admixture exceeding the optimum quantity results in a decrease in maximum relative elongation at break and diminished resistance to abrasion is observed. The study of the volume resistivity showed that the rubbers obtained belong to semiconductor materials. The dependence of resistivity on temperature in the range from 10 to 80°C is plotted. It is shown that the effect of a positive thermal coefficient is observed in all samples. The values of the positive temperature coefficient of resistance in the temperature range of 10–80°C are 0.054–0.285 K~(–1).