AbstractThe influence of cryoground rubber (CGR) on the curing characteristics, physical properties, network structure, and failure behavior of natural rubber (NR) has been investigated. CGR was added at two different levels of curatives and in two different ways (i) in powder form and (ii) in mill‐sheeted form (obtained by mechanical treatment of CGR in a two‐roll mill). The form of CGR and level of curatives affect the processing characteristics and technical properties of CGR–NR blends. The acetone extractables in the CGR were found to affect the curing characteristics, but no significant effect on the physical properties was observed. Model mixes were prepared by adding partially vulcanized NR compound in the matrix of the same compound. A three‐layer model was set up to study the diffusion of sulfur from the NR matrix phase to the CGR phase. Scanning electron microscope studies of the fractured surface revealed that the mechanical treatment of CGR effects improved adhesion of CGR to NR matrix and the compatibility between the two phases. CGR acts as an inert filler in NR.