Preparation and membrane separation performances of quarternized ammonium cationic polyvinyl alcohol

The synthesis of quarternized ammonium cationic polyvinyl alcohol (QPVA⁺) is studied in this article. The effect of synthesis conditions on the degree of substitution (DS) is studied to acquire the optimal synthesis conditions. Polyelectrolyte and polyelectrolyte complex (PEC) membranes of QPVA⁺ and phosphatized anionic polyvinyl alcohol (PPVA⁻) are made by solution casting method. It is found that the flux of polyelectrolyte and PEC membrane, consisting of QPVA⁺ and PPVA⁻ (1 : 1 in molar ratio), is 403 g/m² h, and its separation factor is 970 when the membrane is used in the pervaporation separation of ethanol/water. It is concluded that the hydrophilicity of the membrane and the rigidity of molecular chain segment are enhanced when the anionic and cationic groups are introduced in the PVA, and the membrane separation capability could be adjusted by changing polyelectrolyte material type and cation/anion mole ratio in the polyelectrolyte and PEC.