Capillary Flow Behavior of the Carbon-black-filled Styrene-butadiene Rubber Compounds

Abstract

The rheological properties of carbon-black-filled styrene-butadiene rubber (SBR) compounds of various molecular weight were investigated. Melt fracture phenomena occurred dependent on quantity of added carbon-black and molecular weight of SBR. The extrusion pressure and the apparent shear-rate were determined using a capillary rheometer with the nozzles different L/D ratios. From relationships between shear stress and shear-rate, slip velocity, flow rate(Q) and slip flow rate (Q_s) were estimated. At a low shear stress, the ratio of slip quantity Q_s/Q showed nearly 1, but it decreased with increasing shear stress. Change of Q_s/Q in the case of high molecular weight SBR samples was larger than low molecular weight SBR. From the results of dynamic strain dispersion of non-vulcanized samples, storage modulus largely decreased with increasing quantity of carbon-black filler and strain.