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1728840 
Journal Article 
Reactive blending, reinforcement and curing of NR/BR/EPDM compounds for tire sidewall applications 
Sahakaro, K; Naskar, N; Datta, RN; Noordermeer, JWM 
2007 
1 
Rubber Chemistry and Technology
ISSN: 0035-9475
EISSN: 1943-4804 
80 
1 
115-138 
English 
WOS:000249719900008 
is translation of 10988986 [Reactive blending, reinforcement and curing of NR/BR/EPDM compounds for tyre sidewall applications]
Tire sidewall compounds are generally formulated using NR and BR to achieve the required dynamical properties. The most widely used antiozonant, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), is a staining, toxic and environmentally unfriendly substance. Incorporation of EPDM into NR/BR blends improves ozone resistance, but leads to poor properties because of differences in filter affinity and cure incompatibility of the rubber components. In this work, the cure incompatibility is overcome by utilizing a reactive processing technique, making use of the most commonly used accelerator CBS and sulfur. The entire amount of curatives is first added into the EPDM. After a thermal pretreatment step related to the scorch time of the EPDM, the modified EPDM is mixed with pre-blended NR/BR. The reactive blends show significant improvements of physical properties in comparison with those of conventional straight mixes, due to improvement of the crosslink and carbon black distributions, confirmed by AFM and TEM images. The physical properties of the reactive mixed NR/BR/EPDM blends are equivalent or even superior to regular filled NR/BR blends for tire sidewall applications. The blend with 30 phr of EPDM has excellent ozone resistance while 6PPD can be totally omitted from the formulation.