Characterization of hybrid fillers based on carbon black of different types obtained by impregnation

The paper presents the investigations on obtaining dual phase fillers with preset silica content running a successful impregnation of two completely different types of conventional carbon black with silicasol. The hybrid fillers studied were characterized by atomic absorption spectroscopy and inductively coupled plasma-optical emission spectroscopy. The total pore volume, the average pore diameter, the specific surface area, the oil absorption number, and iodine adsorption of the fillers were also investigated. The distribution of both phases within the hybrid filler obtained and their interpenetration were investigated with scanning transmission electron microscopy-energy dispersive X-ray spectroscopy. The hybrid products obtained were investigated as reinforcing fillers of natural rubber-based composites. The results obtained show that the suggested impregnation with silicasol of conventional carbon black is a perspective method for preparation of carbon-silica dual phase fillers. The method provides an easy control over the quantitative ratio between the two phases. The fillers thus prepared do not change significantly the curing and mechanical characteristics of the vulcanizates, but improve their thermal aging resistance. The isolation of the carbon black aggregates by the silica phase, and the interpenetration of the two phases is a prerequisite to obtain elastomer composites of good mechanical and microwave properties suitable for producing of microwave shielding devices.