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viscal10
Viscosity of a blend of two
polymer solutions
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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.
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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.
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Measured data
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Solids, %
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Visc., cps
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Temp., ºC.
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Solvent, %
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Poise
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Visc. log
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T-Tg
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Tg
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Polymer A sol.1
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Polymer A sol.2
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Polymer B sol.1
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Polymer B sol.2
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Constants
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Polymer 1
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Co =
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WLF
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Log η= C-A(T-Tg)/(B+(T-Tg))
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C1 =
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equation
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C=
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Universal constants
according to Nielsen
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Polymer 2
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Co =
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A=
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C1 =
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B=
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Results
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Enter desired blend
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Poly B weight fraction:
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Polymer A
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Constants
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Co
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Polymer B
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of blend
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C1
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Solids %
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Viscosity, Poise log
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Temp. ºC:
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Viscosity, cps
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