FORMATION OF CARBON BLACK-SULFUR SURFACE DERIVATIVES BY REACTION WITH P2S5

Carbon blacks were treated with P2S5 in the 60 to 500-degrees-C temperature range for increasing times of treatment of up to four hours. A series of experimental methods was applied to follow the formation of sulfur surface derivatives: elemental analysis, basic surface groups analysis by back-titration, ESCA, and FTIR. It was shown that surface carbonyl groups are transformed into thiones whereas, on air exposure, after P2S5 treatment, oxygen content increases significantly, demonstrating the formation of other sulfur groups very sensitive to oxidation. These groups are decomposed upon water extraction of the blacks. The surface properties, as shown by water adsorption isotherms, are modified.