Influence of carbon black amorphous phase content on rubber filled compounds

One of the most widely accepted carbon black surface models, consists in a bulk sphere-like geometry covered by two different carbon structures, small crystalline regions called crystallites and amorphous carbon. Following this approach, three different carbon blacks with similar size but different content in amorphous carbon on their surface were studied. The variation in the surface structure was compared with the size effect using regular N-110, N-220 and N-772∗ (Carbon black grades classified following the ASTM procedure developed by the ASTM D24 Committee on Carbon Black). As a result some of the final compound properties as the filler dispersion obtained by electrical measurements was found to be more dependent on the particle size, while the surface structure showed a relevant influence in the low strain dynamic properties. The vulcanization reaction was also altered by the different carbon phases on the particle surface. The curing process was studied using squalene as a MCV (model compound vulcanization) and HPLC as analytical tool to follow the reaction intermediates at different times.