ISSN:
0032-3888
Schlagwort(e):
Chemistry
;
Chemical Engineering
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
,
Maschinenbau
,
Physik
Notizen:
Simha's equation of state provides the relation between reduced pressure, temperature, and volume (P̃, T̃, and Ṽ, respectively) and the occupied site fraction, y = y (P̃, T̃). The latter theoretical parameter combines the P and T effects on the occupied and unoccupied (“free volume”) part of the model liquid. It can be computed for each liquid once the thermodynamic reducing parameters are known. Empirical correlation between published zero shear viscosity data, η = η (P, T), and y indicates that for n-paraffins and molten polymers η is a single parameter function: η = η (y). The mathematical form of this dependence was explicitly given for n-paraffins. However, for polymers the correlation depends on molecular weight, molecular weight distribution, branching, composition, etc. In Practical terms, η = η (y) should be determined for each polymer by measuring the temperature dependence of η in as wide a range of T as possible. Then pressure effect on η can be determined from η = η(y) plot, knowing the y = y(P̃, T̃) relation.
Zusätzliches Material:
27 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/pen.760251104
