ASSESSMENT OF APPLICABILITY OF CARREAU, ELLIS, AND CROSS MODELS TO THE VISCOSITY DATA OF RESIN SOLUTIONS

In this study, three popular rheological models, which fit adequately well to viscosity data of polymeric materials, are chosen for making a comparative assessment of their applicability to practical data. The resulting nonlinear equations of the three models are solved by using Levenberg Marquardt's algorithm. The assessment of their applicability to practical viscosity data of 66 solutions of two resins in 11 solve nt systems and reported data of other polymers has been analyzed. The Carreau and Ellis models have yielded unique global estimates for vari ous rheological parameters, whereas the Cross model yielded local solu tions. However, both Carreau and Cross models yielded parameter estima tes with low overall residual error. The three models are found to hav e good applicability to viscosity data of resin solutions in good and moderate solvents; however, some deviation is observed when they are t ested for solvents in which the resin has poor solubility.