Effect of nano diamonds on cure characteristics and network structure of NR/SBR vulcanizates

In this study the effect of nano diamond (ND) on cure characteristics and network structure of natural rubber and styrene-butadiene rubber (NR/SBR) blend was investigated. Crosslink density was characterized based on swelling data and cure characteristics was analyzed applying isoconversional approach based on curing curves. It was found that the cure characteristics are affected considerably by incorporating ND in formulation, resulting in lower scorch time and higher curing rate. In addition, ND filled rubbers exhibited decrement in reversion tendency indicating thermal stability improvement of vulcanizates due to lower dissociation of sulfur crosslinks. As Flory-Rehner model revealed in presence of ND the crosslink density of rubber increases compare with the unfilled one. It was speculated that the surface activity of ND which tend to interact with rubber macromolecules dominated the crosslink density and cure characteristics of NR/SBR vulcanizates.