US Patent 9428630 Water-in-oil polyacrylamide-based microemulsions and related methods

A water-in-oil microemulsion, including a polyacrylamide, a fatty acid, a surfactant, an oil continuous phase, and an aqueous discontinuous phase in the oil continuous phase. The fatty acid includes a tall oil fatty acid, oleic acid, or a combination of a tall oil fatty acid and oleic acid. The water-in-oil microemulsion contains 6 to 48 parts by weight of the polyacrylamide, 30 to 62 parts by weight of the fatty acid, and 20 to 44 parts by weight of the surfactant per 100 parts by weight of the polyacrylamide, the fatty acid, and the surfactant combined.