Dielectric properties of thermally degraded chloroprene rubber

We performed dielectric measurements on thermally aged carbon-black-filled chloroprene rubber (CR). Primary and secondary processes were observed in unaged and thermally aged CR. The primary process is due to the cooperative motion of chloroprene chains in CR, and the secondary process is due to the local motion of chloroprene chains. For the primary process, the relaxation time slightly increases and symmetric shape parameter of the loss spectrum decreases with increasing aging time. For the secondary process, the relaxation strength decreases with increasing aging time, and reaches zero after 50 h. These changes in the dielectric relaxation parameters are due to the progress of the dehydrochlorination reaction at the chloroprene chains.