Synthesis and properties of hydrophobically modified polyampholytes

Hydrophobically modified, low charge density polyampholytes were prepared b y copolymerization of acrylamide, [2-methacryloyloxy)ethyl] trimethylammoni um chloride, sodium 2-acrylamido-2-methylpropane sulfonate and a hydrophobi c monomer (N,N-dihexylacrylamide) in a micellar aqueous medium. The resulti ng polymer is soluble in pure water and in sodium chloride aqueous solution s and exhibits improved thickening properties with respect to the unmodifie d polyampholyte due to intermolecular association. This behavior manifests itself particularly in high-salinity media.