Influence of rubber composition on migration behaviors of antiozonants in carbon black-filled rubber vulcanizates composed of NR, SBR, and BR

Migration behaviors of antiozonants in carbon black-filled rubber vulcaniza tes with different rubber compositions of natural rubber (NR), styrene-buta diene rubber (SBR!, and butadiene rubber (BR) were studied at constant temp eratures of 40-100 degreesC and outdoors. Three single rubber-based vulcani zates, three biblends, and three triblends were used. N-Phenyl-N-isopropyl- p-phenylenediamine (IPPD) and N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylediam ine (HPPD) were employed as antiozonants. Migration rates of the antiozonan ts became faster with increasing the temperature. The order of the migratio n rates in the single rubber-based vulcanizates was BR > NR > SBR. The migr ation rates in the vulcanizates containing SBR, on the whole, increased wit h decreasing the SBR content, while those in the vulcanizates containing BE decreased with decreasing the BR content. Difference in the migration beha viors of the antiozonants depending on the rubber composition was explained both by the intermolecular interactions of the antiozonants with the matri x and by interface formed between dissimilar rubbers in the blends. (C) 200 1 John Wiley & Sons, Inc.