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United States Department of Agriculture

Agricultural Research Service

Title: Spray Droplet Size and Extensional Viscosity of Sheared Polymer Solutions

Authors
item Fox, Robert
item Dexter, R - AMERICAN CYNAMID CO
item Zhu, H - OSU/OARDC-AGRIC ENGR DEPT
item Reichard, Donald - ARS (DECEASED)
item Brazee, Ross

Submitted to: Proceedings Annual Conference on Liquid Atomization and Spray Systems
Publication Type: Abstract Only
Publication Acceptance Date: May 22, 1996
Publication Date: N/A

Technical Abstract: Ten polymers which are primary active ingredients in commercial drift retardants were tested. The polymers included poly(ethylene oxide)s, polyacrylamides, and a polyaccharide, with a range of molecular weights. Five were non-ionic and 5 were anionic. These polymers were diluted in distilled water to 100 ppm and tested in a shear test stand. Samples of the solutions were taken after 0, 1.0, 2.3, 3.9, 6.4, and 11.4 passes through a centrifugal pump system. Drop sizes (D[V.5]) produced when the samples were sprayed through an XR8004VH flat fan nozzle were measured with a Phase/Doppler Particle Analyzer. Apparent extensional viscosity and screen factor were measured for all samples. Molecular weight of the polymer was correlated with D[V.5] when unsheared solutions were sprayed, and polymers were considered by chemical type. After being sheared by more than 4 passes through the pump, both non-ionic and anionic polymer-solutions at 100 ppm did not increase D[V.5] much over values for water alone. One non-ionic polymer was tested at 4 concentrations from 100 to 400 ppm; increased concentration did not increase the D[V.5] of sprayed solutions that had been sheared. Tests with an anionic polymer at 100, 200, and 300 ppm found that increased concentration did produce greater D[V.5] even after being sheared. Both apparent extensional viscosity (R-squared = 0.8) and screen factor (R- squared = 0.7) were well correlated with spray D[V.5] for all polymers tested.

Last Modified: 10/30/2014
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