0000000000059864
AUTHOR
R. Jend
Pressure influences on the viscosity of polymer solutions
Of all physico-chemical quantities characterizing the behavior of liquids, the viscosity coefficient η is normally most sensitive to pressure. Early measurements of η(p) date back almost 100 years [1] but they were carried out with very different objectives [2]. Currently, one is particularly interested in polymer solutions, for instance because of the additives to motor oils and of oil recovery. The present paper reports on measurements with polystyrenes of high molecular uniformity in eight different solvents. It confines itself to zero-shear viscosities and discusses the possibilities of discovering the influence of pressure via the molecular structure of the solvent and via its thermody…
Über die möglichkeiten zur bestimmung von mischungsenthalpien und -volumina aus der molekulargewichtsabhängigkeit der kritischen entmischungstemperaturen und -drücke am beispiel des systems trans-decahydronaphthalin/polystyrol
Cloud-point curves and critical curves (Tc = f(p)) have been measured for the system trans-decahydronaphthalene/polystyrene and three different molecular weights of the polystyrene component (2,5 · 106; 3,9 · 105; 1,1 · 105). It turned out that by variation of the pressure the metastable region can be investigated up to the spinodal curve. A comparison of the theta-temperatures and the enthalpy contributions χH (to the Flory-Huggins interaction parameter χ) resulting from the measured critical temperatures according to Shultz-Flory, with the corresponding directly obtained literature data, demonstrates that, although the extrapolation of Tc to infinite molecular weight is feasible, χH obtai…