Oscillatory shear rheology of polystyrene melts filled with carbon black and fullerene

Abstract

Fullerene C₆₀ and submicrometre sized particles of carbon black were used to investigate the size effect of filler particles on the rheological behaviour of polydisperse polystyrene melts. The addition of 5 wt-% carbon black increased the viscosity of all the composite melts relative to their polymer matrixes. The effect of 5 wt-% fullerene nanoparticles on the viscosity of composites depended on the molecular weight distribution of the polymer matrixes. In the polymer with a high fraction of polymer chains below the critical molecular weight for entanglement, the fullerene addition increased the viscosity, similar to carbon black addition. As the molecular weight distribution of the polymer matrix moved to higher values, the influence of fullerene addition on melt viscosity changed, and the viscosity of the nanocomposite was similar to that of the polymer matrix. The effect of fullerene addition on the melt viscosity of the coarse particle composite was also investigated.