INVESTIGATION OF THE INFLUENCE OF WHITE FILLERS ON THE FORMATION OF N-NITROSAMINES IN RUBBER COMPOUNDS

During the past two years, major manufacturers of white fillers have cooperated within the framework of the Committee ''Analytical Working Group White Fillers/N-Derivates'' In a comprehensive investigation concerning the influence of commercial white fillers on the formation of N-nitrosamines in rubber compounds, The whole range of surface areas was taken into account. The fillers were analyzed for their N-nitrosamine content, and the amount of NO(x) bound to the filler surface by adsorption. Their nitrosating potential was determined by reacting the nitrosating substances with dimethylamine. In addition, the N-nitrosamine concentration of an EPDM compound, with 50 phr filler and without filler, containing tetramethylthiuram disulfide as accelerator was determined by extraction of the vulcanizates with methanol and by analysis of the gas phase. This study furthermore investigates the influence of storage time and conditions of fillers and vulcanizates on the N-nitrosamine concentration.