Synergistic effects of gamma pre-irradiation and additional vulcanizing agent in case of ground tire rubber containing vulcanizates

In this study, we investigated gamma radiation treated ground tire rubber (GTR) at different doses and measured the soluble content and the cross-link density of the samples. These results have been evaluated with Horikx's diagram. The results showed that at low doses, the selective chain-scission of the sulphur cross-links is dominant; however, at higher doses, the degradation of the polymer backbone comes to the fore. Natural rubber (NR) based mixtures were prepared in an internal mixer using conventional and two-step mixing, then the samples were vulcanized. Synergistic effects were observed when using radiation treatment and two-step mixing, resulting in improved mechanical properties. In materials where only one treatment was applied, the properties did not change significantly. The morphology of the mixtures was observed using scanning electron micrographs, which showed that the GTR could integrate well into the matrix.