Abstract: The conduction behavior of carbon black(CB) filled poly(methyl vinyl siloxane)(PMVS) vulcanites undergoing thermal cycles or subject to thermal treatment at given temperatures was investigated. The conduction behavior in PMVS/CB crosslinked composites at room temperature followed the prediction of the statistical percolation theory. The negative temperature coefficient(NTC) effect of resistivity corresponded to thermal activation conduction mechanism, while the positive temperature coefficient(PTC) effect was related to the breakdown of conductive network caused by volume expansion. The results revealed that the resistivity-temperature properties during the thermal cycles was gradually changed towards low-resistance, while the change of resistance with variation of time at given temperatures exhibited resistivity relaxation behavior. The conductive mechanisms and corresponding changes in the structure of PMVS/CB responsible for the resistivity-temperature behavior were discussed. At given temperatures, the tesistance relaxation was strengthened with decreasing CB weight fraction. On the other hand, it is strengthened with increasing ambient temperature at given CB fractions.

Key words: Carbon black, Poly(methyl vinyl siloxane), Thermal cycle, Resistivity-temperature characteristic, Resistivity relaxation