The effect of shear rate on the molecular weight determination of acrylamide polymers from intrinsic viscosity measurements

ArticleinJournal of Applied Polymer Science 23(11):3323 - 3339 · June 1979with21 Reads
Impact Factor: 1.77 · DOI: 10.1002/app.1979.070231118

    Abstract

    The rheological response of dilute solutions of high molecular weight polyacrylamides at low shear rates has been measured using a capillary viscometer that provided for a fivefold variation in shear rate at each concentration. The non-Newtonian effects were found to be significant for polyacrylamides with number-average molecular weights exceeding 106. The molecular weight average–intrinsic viscosity relationship most widely used in the literature, [η] = 6.80 × 10−4M, was found to be valid when [η] was measured at high shear rates where the polymer solutions approached Newtonian behavior. A new relationship was developed relating Mn to the intrinsic viscosity extrapolated to zero shear rate.