Viscometric study on the miscibility of polystyrene/brominated polystyrene blends

The miscibility of polystyrene/brominated polystyrene blends (PS/PBrS) was investigated by using dilute-solution viscometry (DSV) method. The intrinsic viscosity and the viscometric parameters of this system have been determined at 20 ± 0.1 °C for prepared several PS/PBrS compositions (85/15, 75/25, 50/50, 25/75, 10/90). The binary systems were prepared in chloroform at five different concentrations; 0.15, 0.30, 0.60, 0.90, 1.20 g 100 ml−1. The miscibility criteria on the basis of the sign of Δ[η] m, Δb and Δb′, which are based on the difference between experimental and ideal values of [η]m, and bm were calculated by applying the Garcia et al., Catsiff–Hewett and Krigbaum–Wall theoretical equations. The thermodynamic parameter, α, modified thermodynamic parameter, β, and interaction parameter, μ, were also estimated. The data obtained from the viscometry studies showed that the examined blends were immiscible in all the compositions range besides the composition (10/90). The results from the DSV method are correlated with the miscibility data obtained for the same blend by differential scanning calorimetry (DSC) find.