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

✍ Scribed by S. M. Shawki; A. E. Hamielec

• Publisher: John Wiley and Sons
• Year: 1979
• Tongue: English
• Weight: 625 KB
• Volume: 23
• Category: Article
• ISSN: 0021-8995
• DOI: 10.1002/app.1979.070231118

✦ Synopsis

The rheological response of dilute solutions of high molecular weight polyacrylamides a t 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 lo6. The molecular weight average- intrinsic viscosity relationship most widely used in the literature, [77] = 6.80 X 10-4%?,,0.66, was found to be valid,when [v] was measured a t high shear rates where the polymer solutions approached Newtonian behavior. A new relationship was developed relating a,, to the intrinsic viscosity extrapolated to zero shear rate.