Characteristics of water‐absorbent polymer emulsions

Abstract

Abstract Water‐in‐Oil (W/O) and Oil‐in‐Water (O/W) type water absorbent polymer emulsions were studied using two different polymerization methods. W/O type water absorbent polymer emulsions were prepared by the inverse emulsion polymerization of ammonium acrylate (AA), the quaternized salt of dimethyl‐aminoethyl methacrylate (DMQ) and acrylamide (AM) with N , N ‐methylene‐bisacrylamide (MBA) as a crosslinker. A pH sensitive water absorbent polymer emulsion was prepared by the conventional emulsion polymerization of diethyl‐aminoethyl methacrylate (DEAEMA) with ethylene glycol dimethacrylate (EGDMA) as a crosslinker. It was confirmed that the water absorption capacity of crosslinked polymers in inverse emulsion was controlled by crosslink density and dissociative charge density, and the crosslinked polyDEAEMA particles had a phase transition property of swelling and shrinking with pH. The dispersions of these water swollen crosslinked polymer particles exhibited an increase in viscosity and thixotropic fluidity.