Grid Turbulence in Dilute High-Polymer Solutions 



pounds. (Solution F-1 has a slightly lower concentration than normal due to 

 spillage loss.) The results for Solution F-5 at 19° and 25"C show that relative 

 viscosity is only slightly temperature dependent, so that the difference between 

 temperatures of 24° and 25°C can be ignored. There is fair agreement between 

 the backward extrapolations of the towing-tank data to one day of age with the 

 predicted values (based on tests of solutions prepared in small quantities) given 

 by the horizontal dashed lines. Polymer chain cleavage has been indicated as 

 the cause of viscosity loss of Polyox solutions (9). 



By comparing the data in Fig. 11 with the preparation methods for the vari- 

 ous solutions in Table 1, some notable relations are found. Comparing Solutions 

 F-8 and F-1, the change from the direct-dispersal technique to the master - 

 solution technique apparently produced no major change in the loss of specific 

 viscosity Vs "^ ^r ~ ^- Comparing Solution F-5 and F-10, the major increase in 

 master -solution stirring time, from about 20 to 40 hours, produced no changes 



in the 



decrease. 



Table 1 

 Preparation Methods for Towing-Tank P301B 

 Solutions Tested with the Caraher Viscometer 



55 



