Film and latex forms of silica-reinforced natural rubber composite vulcanized using electron beam irradiation.

A thorough study was undertaken of the synthesis of natural rubber-silica treated with bis-(3-triethoxysilylpropyl) tetrasulfane (NR/TSi) vulcanized using electron beam irradiation (EB) and sulfur by varying the EB dose. The surface treatment of silica was confirmed using Fourier-transform infrared spectroscopy and scanning electron microscopy images. Composites were cast and vulcanized in film and latex forms compared with sulfur vulcanization. Investigation covered the mechanical properties, thermal stability, swelling resistance, and degradation under heat and humidity testing of the NR/TSi composites. It was found that the TSi had great dispersal in the NR matrix. TSi in NR matrix had a positive effect on mechanical properties, swelling in water and toluene, and thermal stability. Increasing the radiation intensity up to 250 kGy led to superior mechanical properties but for further increase in the radiation intensity, the tensile strength dropped. Degradation under thermal and humidity testing showed that the un-vulcanized composite had higher physical degradation than the vulcanized samples. Therefore, NR/TSi vulcanized using 200 kGy EB vulcanized in latex form had the greatest mechanical properties for various applications without producing any residual vulcanizing agent.