Rheology of Poly(Vinylidene Fluoride)/Polyethersulfone Blend Concentrated Solutions

摘要

Rheological properties of poly(vinylidene fluoride)(PVDF)/polyethersulfone(PES) mixtures in dimethyl acetamide (DMAc) were investigated. When the total polymer concentration was kept unchanged and the blend ratio was varied by changing the PES content, the influence of PES content on apparent viscosity, zero shear viscosity, Non-Newtonian index, viscose flow activation energy was studied. When the blend ratio was kept constant the influence of concentration on zero shear viscosity (nO) and viscose flow activation energy (En) were studied. The results show that the fluids behave shear-thinning characteristics. Under lower shear rate, the apparent viscosity decreases slowly, and shows a characteristic shear rate γ_c. When the shear rate is above γ_c, the apparent viscosity decreases sharply and shows a strong dependence on the shear rate. The zero shear viscosity of solutions decreases when less PES is introduced into the solution and increases as the content of PES surpasses 3%. The viscose flow activation energy of solutions with different PES content is calculated after Arrhenius equation. The Non-Newtonian index reaches the minimum with the increase of PES content and temperature. The nO of the blend solution has a higher dependence power on concentration. The value of En increases slowly with the increase of concentration, and that of the solution with blend ratio 9:1 is lower than that of pure PVDF solution.