Distribution ratio of carbon black in polyisobutyrene/polyisoprene rubber blends using high-resolution solid-state 13 C NMR

We establish the 13C nuclear magnetic resonance (NMR) method as the best available method for the evaluation of carbon black (CB) distribution in rubber blend. We find that the line widths of NMR peaks increase as CB contents increase. Using this phenomenon it is found that, in polyisobutyrene rubber (IIR)/polyisoprene rubber (IR)/CB composites, CB more easily distributes in IR than in IIR. And we can estimate that more than 70% of CB is distributed in to the IR phase, irrespective of CB content.