The Effect of Novolac and Graphite Polycrystal on the Acetone Penetration and Thermal Resistance of Nanocomposites Based on Nitrile Rubber

Developments of high diffusive environments in coincidence with emerging fluids with strong ability to destroy polymeric systems have resulted in rapid deformation and destruction of polymeric parts when in contact with such aggressive environments. Therefore، nowadays، there is a great need to develop highly resistant materials towards aggressive chemicals and harsh conditions. In this paper the effect of graphite polycrystal powders and novolac type phenolic resin has been experimentally studied towards acetone diffusion and thermal stability of polyacrylonitrile butadiene rubber/novolac/graphite polycrystal nanocomposites. The results obtained from dynamic mechanical thermal analysis (DMTA) and swelling in acetone showed that after 32 h samples reached to 94. 2% of final swelling state. By using Avrami equation and swelling experimental data، the functionality of Ln (m/m0) to novolac and graphite polycrystal weight fraction and test duration time were evaluated. This theoretical equation evaluated and predicted the amount of Ln (m/m0) with 5. 92% error after 32 h. Increases in graphite polycrystal content were followed by decreases in diffusion of acetone and modulus، before glass transition temperature، and increased thermal stability and thermal resistance of the nanocomposites. Increases in novolac content by 35 wt%، decreased glass transition temperature، thermal stability and thermal resistance of the nanocomposites. In nanocomposite، containing 45 wt% of novolac، dynamic mechanical thermal analysis (DMTA) data and scanning electron microscope (SEM) images showed phase separation of thermoset and elastomer in the nanocomposite blend.