Home viscal10                 Viscosity of a blend of two polymer solutions
This program calculates the viscosity of a blend of two polymer solutions at different non-volatile content and temperature. As input two viscosity and solids measurement of each polymer are required. A combination of the William, Landel and Ferry (WLF) equation and the Fox equation is used in the calculation. The constants in the WLF equation are according to Nielsen and reasonable accurate for most polymers. For a specific polymer the constants can be adjusted to increase the accuracy. The assumption is made that the Tg of a polymer solution decreases linear with the solvent fraction. Tgs = Co +C1Ws, Tgs = solution Tg, Co, C1= constants for polymer solution, Ws = weight fraction of solvent. 
1/Tgb = W1/Tg1 + W2/Tg2 , Tgb = Tg of polymer solution blend, W1,2 = weight fraction of polymer solution 1, 2, Tg1,2 Tg of polymer solution 1 an 2.
Measured data Solids, %

Visc., cps

Temp., C. Solvent, % Poise Visc. log T-Tg Tg
Polymer A sol.1
Polymer A sol.2
Polymer B sol.1
Polymer B sol.2


Polymer 1 Co =     WLF

Log η= C-A(T-Tg)/(B+(T-Tg))

  C1 =     equation C=

Universal constants according to Nielsen

Polymer 2 Co =       A=
  C1 =       B=
Enter desired blend       Poly B weight fraction:
Polymer A         Constants Co
Polymer B         of blend C1
Solids %         Viscosity, Poise log
Temp. C:         Viscosity, cps
M.L.Williams, R.F.Landel and  J.D.Ferry, J.Am.Chem.Soc.77,3701(1955)
L.E.Nielsen, Polymer Rheology, Marcel Dekker, 1977,pp.33,74,133

Automatic recalculation 

Last edited on:

October 20, 2010

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