Effect of electron beam irradiation on aging time, thermal vulcanization kinetic and mechanical properties of SSBR/NR/BR compounds filled with silica

A ternary rubber compound based on solution styrene-butadiene rubber (SSBR), natural rubber (NR) and polybutadiene rubber (BR) filled with silica were studied. This uncured compound was electron beam irradiated at different doses and later was vulcanized. The influence of electron beam irradiation on the pre-vulcanized compound at different radiation doses, and a later aging time, on Mooney relaxation were investigated. These results were analyzed using the Wu-Abbott model and the generalized Maxwell relaxation model and were associated with swelling measurements, confirming the influence of the crosslinking reaction under the irradiation process before the thermal vulcanization. The impact of the irradiation treatment on the thermal vulcanization kinetics was also studied at several temperatures in the range between 140 to 180 degrees C. The reduction of the induction time of the compounds with the radiation dose was confirmed by means of rheometer test. The relationship between the induction time and the cure temperature approaches Claxton-Liska model. The cure kinetic of rubber compounds was analyzed in the frame of the Isayev-Deng model showing satisfactory results. After the thermal curing, swelling measurements and mechanical properties were done to characterize the ternary rubber compounds, confirming the influence of the irradiation process on the obtained morphology and performance.