Thermal Degradation of Elastomer Based Nanocomposites

The thermal degradation behavior of nanocomposites based on Styrene Butadiene Rubber (SBR), Polybutadiene Rubber (BR) and Acylonitrile Butadiene Rubber (NBR) with 19%, 34% and 50% acrylonitrile contents respectively, and sodium montmorillonite (designated as N) and octadecyl amine modified sodium montmorillonite (designated as OC) clays have been investigated. The thermal degradation pattern depends on the type of the matrix and the clay, polarity of rubber and loading of the filler. In general with the addition of the modified clay, there is a significant change in thermal stability. For example, there is a shift of T _max , (the temperature at which rate of degradation is maximum) towards higher temperature and a decrease in the rate of degradation. The activation energy of degradation calculated from the Flynn-Wall-Ozawa method increases with the loading of the clay up to 4 parts. Filler loading beyond 4 parts in NBR with 34% acrylonitrile content causes a decrease in the T _max value. The degradation rate for the same rubber in air is generally higher than that of the same in the nitrogen atmosphere. The results have been explained by using X-ray data.