POLYMER BLEND UNDER SHEAR-FLOW - A THERMODYNAMIC STUDY

The effect of shear flow on the phase separation behaviour of polymer blends has been investigated for the model system poly (ethylene - co- vinyl acetate) (EVA)/solution chlorinated polyethylene (SCPE). The eff ect of shear on the cloud point and on the kinetics of phase separatio n for the blend have been investigated. Shear has been applied by conf ining a polymer sample between two parallel glass plates, the bottom o ne remaining stationary while the top one rotates at a constant angula r speed. The effect of flow has been investigated as a function of tem perature by light scattering and the results have been correlated with dynamic mechanical thermal analysis (DMTA) measurements carried out o n quenched samples. The results are consistent with the existence, und er shear, of additional miscibility gaps at temperatures lower than th e quiescent coexistence curve.