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The effect of shear rate on the molecular weight determination of acrylamide polymers from intrinsic viscosity measurements
Author(s) -
Shawki S. M.,
Hamielec A. E.
Publication year - 1979
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1979.070231118
Subject(s) - viscometer , rheology , shear rate , polymer , thermodynamics , intrinsic viscosity , capillary action , viscosity , shear (geology) , apparent viscosity , materials science , polymer chemistry , newtonian fluid , reduced viscosity , chemistry , composite material , physics
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 10 6 . The molecular weight average–intrinsic viscosity relationship most widely used in the literature, [η] = 6.80 × 10 −4 M n 0.66, 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 M n to the intrinsic viscosity extrapolated to zero shear rate.