Effect of carbon black and silica fillers in elastomer blends

The effects of carbon black and pyrogeneous silica fillers on the interfaci al properties of a homopolymer [polybutadiene, (PB)] and a terpolymer [brom inated poly(isobutylene-co-p-metliylstyrene), (BIMS)] are reported. Neutron reflectivity (NR) was used to study the interfacial structure. The results are complemented by scanning transmission X-ray microscopy (STXM) and late ral force microscopy (LFM), which were used to probe the morphology and sur face lateral force. Small-angle neutron scattering (SANS) was used to chara cterize the size and surface properties of the filler aggregates in elastom ers. Our results show that the interfacial behavior of PB/BIMS is more sens itive to carbon black than to silica. The interfacial broadening is signifi cantly slowed down with addition of merely phi (CB) = 0.01 (volume fraction ) carbon black fillers. This volume level is much lower than that used in b ulk rubbers (phi (CB) greater than or equal to 0.1). Pyrogeneous silica has a less pronounced effect on the interfacial characteristics. When both car bon and silica are incorporated into the PB layer, the effect of carbon bla ck is offset by silica fillers.