DIELECTRIC-RELAXATION AND MECHANICAL-PROPERTIES OF NATURAL AND CHLOROPRENE RUBBER WITH SOME NITROANILINE ADDITIVES

A systematic dielectric study over a frequency range from 400 to 10 MH z was carried out on natural rubber and chloroprene rubber with a smal l amount of nitroaniline additives. Three absorption regions were obta ined as a result of the analysis of the curves relating dielectric los s epsilon '' with frequency. The first absorption region in the lower- frequency range could be attributed to the Maxwell-Wagner effect. The second absorption region which could be attributed to the ingredients added to rubber was found to be nearly the same for doped and undoped natural rubber samples, while it decreases by the addition of aniline derivatives to chloroprene rubber samples. The third region which is a ssociated with Debye losses is found to be also nearly the same for na tural rubber samples, while it decreases by the addition of aniline de rivatives to chloroprene rubber; this decrease is interpreted accordin g to the peptizing effect of aniline derivatives. For the expired chlo roprene rubber gum, aniline derivatives were added and the mechanical and electrical behavior was improved to approach the unexpired one. (C ) 1996 John Wiley & Sons, Inc.