Maleic acid/phenylene diamine adducts as new antioxidant amide polymers for rubber (NR and SBR) vulcanizates

摘要

Maleiyl phenylene amide polymers were prepared by the condensation of maleic acid with phenylene diamine (meta and para) in boiling o-xylene using a Dean & Stark apparatus. The prepared polymers were investigated using IR spectroscopy and micro-analysis. The compounds were incorporated into natural rubber (NR) and styrene butadiene rubber (SBR) mixes and the rheo-metric characteristics were determined using an oscillating disc rheometer. The prepared polymers were evaluated as antioxidants in NR and SBR vulcanizates. The physico-mechanical properties of the rubber vulcanizates were measured before and after exposure to accelerated thermo-oxidative aging. The results revealed that the prepared amide polymers were good antioxidants for rubber vulcanizates exceeding the commercial antioxidant phenyl β-naphthylamine (PBN). In addition, the p-maleiyl phenylene amide polymer has better efficiency as an antioxidant than the m-maleiyl polymer adduct. The vulcanizates containing the maleiyl polymer adducts subjected to UV irradiation for 200 h exposure, showed significant stabilization against UV radiation. The importance of these polymers is due to the very low volatility and having no health hazards when incorporated in rubber.