Phase size/composition dependence in immiscible blends: Experimental and theoretical considerations

The influence of composition on phase size in immiscible polymer blends is examined both experimentally and theoretically. It was found for eight noncompatibilized blends, of widely varying particle size morphology, that a master curve of phase size versus log‐relative composition could be obtained by shifting the data along the volume fraction axis. The magnitude of the shift factors (aϕ) correlates with the interfacial tension and viscosity ratio of the systems. The theoretical dependence of the master curve is proportional to ϕ + ϕ2 dependence as in Tokita's theory, but estimation of the coefficients to the ϕ and ϕ2 terms indicates that the influence of power and shear stress on breakdown of the dispersed phase is significantly overestimated by the theory. A master curve is also generated for four compatibilized blends and the dispersed phase sizes are significantly less dependent on composition.