The possibility of replacement of active fillers, e.g. carbon black, f
or cheap products, e.g. mica, were investigated. The physical mechanic
al properties of SBR composites with mica and carbon black, using a co
nstant total filler content (50 phr) have been studied. Tensile streng
th shows the best results when 10 phr of mica are used in combination
with 40 phr of carbon black. These results are better than those for f
ormulations in which carbon black is used alone. Relationships between
mechanical behaviour and structure have been examined under scanning
electron microscopy (SEM) on the fracture surface of the compositions.