Styrene-Butadiene Rubber Filled with Fluorinated Carbon Black

Abstract

Abstract A comparison is made of the properties of an SBR 1502 containing twenty volume percent of conventional furnace black, or one of three fluorinated blacks. Fluorination slows the rate at which the filler incorporates and disperses into the rubber. Final mixing torque decreases as the degree of fluorination increases, apparently due to a reduction in surface energy of the filler. Compositions with fluorinated blacks have reduced scorch times and decreased cure rates relative to compositions with normal furnace black. This is attributed to acidity of the fluorinated blacks. Scorch time increases in a linear fashion with pH of the filler. Tensile strengths of samples containing fluorinated blacks are about seven times that of a gum composition, but about 30% less than vulcanizates with regular furnace black.