Rigid rod water-soluble polymers

For many applications such as enhanced oil recovery, it is essential to have an extremely water soluble shear stable polymer that can impart high viscosity at very low concentration for economic reasons. It is known that rigid rod polymers can deliver high viscosity at low molecular weight compared with the traditionally used flexible chain polymers such a hydrolyzed polyacrylamides. Polymers with helical or double stranded conformations may be considered as truly rigid rod in solution. New sulfonated water soluble aromatic polyamides, polyureas, and polyimides were prepared via interfacial or solution polymerization of sulfonated aromatic diamines with aromatic dianhydrides, diacid chlorides, or phosgene. Some of these polymers had sufficiently high molecular weight (<200,000), extremely high intrinsic viscosity (∼ 65 dL/g), and appeared to transform into a helical coil in salt solution. These polymers have been evaluated in applications such as thickening of aqueous solutions, flocculation and dispersion stabilization of particulate materials, and membrane separation utilizing cast films. © 1996 John Wiley & Sons, Inc.