Preparation and retention performance of crosslinked and hydrophobically associating cationic polyacrylamide

Abstract

“Water-in-water” emulsions of cross-linked and hydrophobically associating cationic polyacrylamide (CHCPAM) with cationic groups (methacrylatoethyl trimethyl ammonium chloride, DMC), hydrophobic groups (octadecyl methacrylate, OA), and cross-linked groups (N, N’-methylene bisacrylamide, MBA) were prepared by dispersion polymerization. The structure of the copolymer was confirmed by FTIR and 1HNMR analyses. The prepared “water-in-water” emulsions possessed high solids content, low viscosity, good stability, and water solubility. Optical microscope images showed that the diameters of most emulsion particles were several microns. Appropriate concentrations of OA and MBA for a stable dispersion system were in the range of 0 to 0.1 wt% and 0 to 50 ppm. “Water-in-water” emulsions of CHCPAM can be directly used as a retention aid without further processing. They have a comparative retention rate, better anti-shearing ability, and better salt resistance, compared to commercial CPAM. The cross-linked structure of CHCPAM contributed to the anti-shearing ability. Intermolecular and intramolecular hydrophobic association of CHCPAM was the most important factor in improving resistance to salt.

Keywords

• Hydrophobic association
• Cross linking
• Polyacrylamide
• Dispersion polymerization
• “Water-in-water”