An AFVS model for polymer solutions: New scaling relationship

Abstract

Abstract:The altered free volume state (AFVS) approach developed by Kulkarni and Mashelkar has been extended to develop a model for the viscosity of polymer solutions. The effect of polymer concentration, molecular weight and electrolyte concentration is shown to be satisfactorily explained in the framework of AFVS model. The regimes of viscosity behaviour have been defined for the systems investigated and the transitions involved identified. The approach leads to the identification of a surprisingly simple and unique scaling parameter ~p, which enables excellent concentration-molecular weight superposition.

Effect of the particle size distribution on the low shear viscosity of high‐solid‐content latexes

“…The prediction of the viscosity becomes particularly complicated when the PSD is taken into account. Despite important recent progress in the study of the rheological behavior of concentrated colloidal dispersions as a function of the physicochemical characteristics of the dispersion and the size distribution of the dispersed phase,19–22 not much effort has been dedicated to quantitatively analyzing the magnitude of the parameters, especially the PSD 23…”

On a generalised viscosity equation for polymer solutions

“…(14) fits the experimental data only in a piecewise linear manner with each linear segment perhaps corresponding to different concentration regimes. Expectedly, this behaviour is also similar to that predicted by the AFVS model for polymer solutions [1]. Thus, the extensive data analysis reported by Kunnen, in a sense serves as a further validation of the AFVS model for polymer solutions and suggests that the model need not be restricted to polymer solutions and latices but may be of more general validity to include viscosity behaviour of other binary liquid systems like liquid mixtures, dispersions etc.…”

“…Moreover, by plotting t/r and g in the form predicted by eq. (7) allows the relationship to be represented by a piecewise linear function (see figure 1) with each linear segment corresponding to a particular solution regime characterised by its state of entanglement [1]. Within each regime, the parameters 0~ and 6 (and fl and B~) in eq.…”

“…Recently, Kulkarni et al [1] have extended the altered free-volume state (AFVS) concept of Mashelkar and Kulkarni [9] to develop a generalised relationship for the viscosity of polymer solutions. From their work emerges a new sealing parameter ~0p which allows excellent concentration-molecular weight superposition *) NCL Communication No.…”

“…Recently, three publications [1][2][3] have appeared in this journal regarding a generalised viscosity equation for polymer solutions. Although it may not be readily apparent, to a certain extent these works are complimentary to one another and in this note we develop a common framework to demonstrate this aspeet.…”