The Shear‐Dependent Phase Separation Behavior of the Ternary Blend Polystyrene/Polyvinyl Methyl Ether/Styrene–Acrylonitrile Copolymer

Abstract

The phase behavior and phase separation dynamics of a PS/PVME/SAN ternary blend using light scattering under a shear rate range of 0.1∼40 s−1 were investigated. The cloud point temperature first increases and then decreases with the increase of shear rates. At higher shear rates, the cloud point temperature again increases. The phase separation behavior in the early and later stages under shear field can be explained by the Cahn–Hilliard theory and the exponential growth law, respectively. The delay time τ d , the apparent diffusion coefficient D app, the growth rate R(q), and the exponent term show strong dependence on the difference between the experimental temperature and the cloud point temperature (ΔT), and on the shear rates. Compared with PS/PVME binary blends at lower shear rates, τ d for a PS/PVME/SAN ternary blend is smaller, while at higher shear rates τ d is larger. At higher shear rates, the introduction of the third component SAN to a PS/PVME binary blends slows the phase separation process.