EPDM incorporated into blends of natural rubber/butadiene rubber (NR/BR) improves ozone resistance. In this work, the inferior mechanical properties of NR/BR/EPDM blends generally obtained by conventional straight mixing are overcome by utilizing a reactive processing technique. The entire amount of curatives, based on a commonly employed accelerator N-cyclohexyl-2-benzothiazole sulfenamide (CBS) and sulfur, is first added into the EPDM phase. After a thermal pretreatment step tuned to the scorch time of the EPDM phase, the modified EPDM is mixed with premasticated NR/BR. The reactive blend vulcanizates show a significant improvement in tensile properties: tensile strength and elongation at break, as compared to those prepared by straight mixing, in both gum and carbon black-filled blends. The increase of tensile properties in gum and filled reactive blend vulcanizates does suggest that the reactive processing technique leads to more homogeneous blends due to, either a better crosslink distribution, or more homogeneous filler distribution, or both.
- reactive processing
- Tire sidewall
Sahakaro, K., Naskar, N., Naskar, N., Noordermeer, J. W. M., & Datta, R. (2007). Blending of NR/BR/EPDM by reactive processing for tire sidewall applications: Part I - Preparation, cure characteristics and mechanical properties. Journal of applied polymer science, 103(4), 2538-2546. https://doi.org/10.1002/app.25088