Preparation of poly(acrylonitrile-methacrylate) membrane via thermally induced phase separation: effects of MA with different feeding molar ratios

Abstract

We report the preparation and performance of poly(acrylonitrile-methacrylate) (AN-MA) flat-sheet membranes with various MA feeding ratio via thermally induced phase separation, in which the membrane forming system consisted of AN-MA, ethylene carbonate (EC), and triethyl citrate (TEC). The effects of the preparation conditions, such as the MA feeding mole ratio, EC content in the mixed diluent, and AN-MA concentration on the pore structure, porosity, water flux, and mechanical properties of the AN-MA membranes were studied. The poly(acrylonitrile-methacrylate) (AN-MA mole ratio 85/15, 80/20, 75/25) copolymers were synthesized by emulsion polymerization. The AN-MA copolymers are melt processable in the temperature range of 130–180°C. The morphology of the resulting membrane gradually changes from a typical bicontinuous structure to a cellular structure upon increasing the polymer concentration and EC content in the mixed diluent. The water flux of AN-MA microporous membranes increased and subsequently declined as the MA feeding molar ratio increased in the polymerization system. In addition, the mechanical properties of the AN-MA membranes increased gradually. Consequently, the properties of the AN-MA membranes were optimal when the MA feeding molar ratio was 20 mol%. Correspondingly, the membrane exhibits a relatively high water flux (66.0 L/(m2 h)) and porosity (75%) when the ternary system contains 60 wt.% EC in the mixed diluent and 9 wt.% 80/20AN-MA. In addition, the membrane exhibits a higher tensile strength (4.6 MPa) and elongation (43.8%).