Effect of iron oxide on the vulcanization and electrical properties of conductive butyl rubber composites

Rubber ceramic composite, negative temperature coefficient of conductivity (NTCC) thermistors, are widely used in industry because of the high dependence of their electrical conductivity on temperature. The effect of iron oxide (Fe3O4) on the vulcanization process, DC conductivity, thermoelectric power, dielectric constant and I–V characteristics have been measured. Also the conduction mechanism is discussed. A hot‐pressing technique has been used to enhance the microstructure core of rubber composites. It has been found that Fe3O4 acts as a catalyst during vulcanization process and the characteristic time constant during vulcanization decreases as the content of Fe3O4 increases. © 2000 Society of Chemical Industry