Silica and aluminum hydroxide filled compounds. Processing and vulcanization monitoring

This work discusses the processing and vulcanization of silicone compositions with aluminum hydroxide (ATH) and silica as fillers. The variables investigated are the silica amount and the type of ATH used, whether surface treated or not, and the results obtained for these compositions are compared with those for pure gum. Cure parameters were provided by an oscillating disk rheometer. Processing was followed in a Haake torque rheometer to monitor variation during filler addition and crosslink formation. It was observed that by using surface treated ATH a better dispersion of the filler in the polymeric matrix was possible and that the mixtures, although presenting a viscosity increase imparted by silica, showed an accelerated cure ratio. (C) 2001 Elsevier Science Ltd. All rights reserved.