Synthesis and Performance of a Salt-Tolerant Poly(AM/NVP/APEG/DMAAC-18) Polymer

A salt-tolerant polymer based on hydrophobically associating water-soluble polymers of 1-vinyl-2-pyrrolidone, allyl polyethylene glycol, acrylamide, and N,N '-dimethyl octadecyl allyl ammonium chloride has been synthesized. Salt thickening and rheological performance of the polymer solutions have been studied. Polymer solutions have demonstrated an excellent uninterruptedly thickening ability within a wide range of salt concentrations. When concentrations of NaCl and CaCl2 reached 19.9 and 19.3%, the apparent viscosity of a 1% polymer solution increased to 660 and 330 mPa s, respectively. Meanwhile, polymer solutions containing high NaCl or CaCl2 concentrations showed good viscoelasticity, shear resistance, and temperature resistance. A scanning electron microscopy showed that increase in a salt concentration enhanced the hydrophobic association strength of polymer solutions and increased the density of the formed network structure, which was macroscopically manifested as a viscosity increase. The results of this study may promote the research and development of polymers resistant to extreme salt concentrations.