Synthesis and Properties of Hydrophobically Modified Polyampholytes

Hydrophobically modified, low charge density polyampholytes were prepared by copolymerization of acrylamide, [2-methacryloyloxy)ethyl] trimethylammonium chloride, sodium 2-acrylamido-2-methylpropane sulfonate and a hydrophobic monomer (N,N-dihexylacrylamide) in a micellar aqueous medium. The resulting polymer is soluble in pure water and in sodium chloride aqueous solutions and exhibits improved thickening properties with respect to the unmodified polyampholyte due to intermolecular association. This behavior manifests itself particularly in high-salinity media.