Curatives, which are considered to be polar molecules,
generally exhibit greater diffusion into natural
rubber, resulting in differences in the reactant concentrations
and, thus, an uneven crosslink distribution and inferior
tensile strength. In addition, the reduced tensile
strength of the carbon-black-filled NR/R-EPDM blends
could be further explained by two factors. First, the number
of effective network chains decreased; the curing agent