Radiation cross-linking technology and co-vulcanization of natural rubber/ethylene-propylene diene monomer blends

Abstract

Natural rubber (NR)/ethylene-propylene-diene rubber (EPDM) blends with different blending ratios were prepared, the heat-vulcanized NR/EPDM vulcaniztes were analyzed by the stress-strain test, the blend with the most serious co-vulcanization problem in the process of heat-vulcanization was selected for radiation processing with diffe-rent radiation absorption dose by radiation cross-linking technology, and the optimal radiation absorption dose was preferred. Radiation treatment of the heat-vulcanized NR/EPDM vulcaniztes with different blending ratios was carried out with the optimal absorption dose, and the properties of the heat-vulcanized NR/EPDM vulcaniztes before and after radiation treatment were compared. The results showed that the comprehensive mechanical properties of the heat-vulcanized NR/EPDM vulcanizte were the worst when the mass ratio of NR to EPDM was 40/60; when the radiation absorption dose was 100 kGy, the comprehensive mechanical properties of NR/EPDM blends were the best, and modulus at 100% of NR/EPDM blends with different blending ratios all increased and there was no significant difference in the magnitude of the increase in modulus at 100% of NR/EPDM blends with different blending ratios after radiation treatment; the curves of tensile strength and elongation at break of NR/EPDM blends with different blending ratios all changed from the “U-shaped” before radiation treatment to the approximate linear after radiation treatment; after radiation treatment elongation at break of NR/EPDM blends all decreased and the magnitudes of the increase in elongation at break of EPDM phase were larger than those of NR phase in NR/EPDM blends.