Silicone rubber/benzoxazine resin‐based nanocomposites: A study on compatibility and thermal stability

Abstract

AbstractIn this study, blends of silicone rubber (SR) and benzoxazine (BZ) were prepared accompanied by ethylene propylene diene monomer grafted with maleic anhydride (EPDM‐g‐MA) as the compatibilizing agent. A total of 3 phr MA grafted EPDM showed the most favorable grafting efficiency and relatively lower gel content. Results showed that 8 phr (EPDM‐g‐MA) was the optimal compatibilizer content in the 85/15 SR/BZ blend, which was used for further studies. Morphological studies proved that the greatest reduction in the dispersed droplet size (from 1.32 to 0.23 μm) occurred at this optimal compatibilizer loading (8 phr). The lowest difference between the glass transition temperatures of the blend components was observed at the 8 phr compatibilizer content, which was confirmed by DMTA. The mechanical and curing characteristics of compatibilized and uncompatibilized blends were also studied. The results evinced that the tensile strength of the compatibilized samples was higher than that of the uncompatibilized blends. Thermal studies on the 85/15 SR/BZ blend and nanocomposites containing 1, 3, and 5 phr polyhedral oligomeric silsesquioxane (POSS) nanoparticles revealed that the thermal stability of nanocomposites containing 1 and 3 phr POSS was superior to that of the nanocomposite with 5 phr POSS.