Inverse emulsion polymerization: a strategy for synthesizing acrylamide copolymer to enhance kaolin flocculation

Abstract Polyacrylamide‐based flocculants are extensively used for kaolin separation by flocculation. In this work, the inverse emulsion polymerization method was adopted to synthesize acrylamide and 3‐acrylamidopropyl trimethyl ammonium chloride (APTMAC) copolymer with an 80:20 mol L −1 reaction feed ratio. Structural characterization of the copolymer was performed using NMR and Fourier transform infrared spectroscopy. Gel permeation chromatography and zeta potential analysis were used to determine molecular weight and charge on the polymer, respectively. Particle morphology was determined by SEM. The influence of monomer and emulsifier concentration on the polymer molecular weight was studied. Inverse emulsion polymerization can produce high molecular weight copolymers while maintaining low viscosity and facilitates better processability and handling. The method also enhances good heat dissipation and mixing efficiency, with higher solid content overcoming the challenges of viscosity build‐up and thermal instability. The synthesized copolymer exhibited a molecular weight of 1 × 10 6 g mol −1 and a zeta potential of ca 40 mV. Flocculation performance was examined using a 3 wt% kaolin suspension and the flocculant showed 90% transmittance at a very low dosage of 4 ppm. These findings demonstrate the potential of APTMAC‐based copolymers for efficient flocculation of kaolin suspensions and other possible anionic minerals. © 2025 Society of Chemical Industry.