S. Haseebuddin et al., TEMPERATURE-DEPENDENCE OF VISCOSITY OF POLYURETHANE POLYOL SOLUTIONS - APPLICATION OF RHEOLOGICAL MODELS, Journal of applied polymer science, 59(1), 1996, pp. 29-36
Polyurethane polyols were synthesized by reacting the diols with polyi
socyanates. Viscosity of their 50% (w/w) solutions in various solvents
has been determined at different temperatures by using Haake Roto Vis
co RV12 Rotational Viscometer. The temperature dependence of viscosity
data was solved by Levenberg Marquardt's algorithm by using nonlinear
regression models based on WLF, Vogel, and Arrhenius equations. The T
-g values obtained from WLF and Vogel equation are comparable to each
other and these equations can be satisfactorily used for the analysis
of temperature dependence of viscosity data of oligomer solutions. The
residuals are random and the absolute average percentage error in ana
lyzing the viscosity data by these equations is minimum. The values of
constants in WLF equation are found to be system dependent and adjust
able parameters. The predicted In eta values obtained from WLF and Vog
el equations fit well with the plots of experimental In eta values as
a function of temperature. (C) 1996 John Wiley & Sons, Inc.