Micrometric gilsonite acts as filler in NR and CB/NR compounds,
and low mechanical interlocking with the rubber matrix is
observed. Rheometric tests and mechanical properties indicate synergic effect of gilsonite and CB in some composites. This
behaviour could be related to sulphur and zinc found in gilsonitwhich modifies the kinetics of the vulcanization reaction and the
structure of the cross-linked network, because of the wellknown
effect of sulphur and zinc in natural rubber curing process. The
effect of gilsonite on mechanical properties depended of the
vulcanization system, especially the modulus under compressivloads and abrasion resistance. Gilsonite increases the dielectric
strength of carbon black reinforced natural rubber and facilitates
the incorporation of carbon black during mixing. These resultsuggest that gilsonite could be used as a filler in natural rubber
compounds regarding the low cost and availability of gilsonite.