EFFECT OF CARBON BLACK AND SILICA FILLERS IN ELASTOMER BLENDS

The effects of carbon black and pyrogeneous silica fillers on the interfacial properties of a homopolymer (polybutadiene, (PB)) and a terpolymer (brominated poly(isobutylene-co-p-methylstyrene), (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 lateral force microscopy (LFM), which were used to probe the morphology and surface lateral force. Small-angle neutron scattering (SANS) was used to characterize the size and surface properties of the filler aggregates in elastomers. Our results show that the interfacial behavior of PB/BIMS is more sensitive to carbon black than to silica. The interfacial broadening is significantly slowed down with addition of merely CB ) 0.01 (volume fraction) carbon black fillers. This volume level is much lower than that used in bulk rubbers (CB g 0.1). Pyrogeneous silica has a less pronounced effect on the interfacial characteristics. When both carbon and silica are incorporated into the PB layer, the effect of carbon black is offset by silica fillers.