Peroxide vulcanization of natural rubber. Part I: effect of temperature and peroxide concentration

Abstract Four different peroxides as curing agents were used to prepare vulcanizates based on natural rubber (NR). The effects of temperature and peroxide concentration on the vulcanization characteristics of rubber compounds, cross-link density ( ν ) and physical-mechanical properties of equivalent vulcanizates were investigated. The results revealed that the vulcanization temperature and also the relative amount of peroxide decomposition products are of significant importance in the properties of vulcanizates. Lower vulcanization temperature and lower concentration of peroxides were found to be better factors, showing a proper balance between the degree of cross-linking of the rubber and degradation of the macromolecular chains by side reactions in relation to the crystallization of NR, which imparts vulcanizates based on NR outstanding properties.