G. Sadowski, A SQUARE-WELL BASED EQUATION OF STATE TAKING INTO ACCOUNT THE CONNECTIVITY IN CHAIN MOLECULES, Fluid phase equilibria, 149(1-2), 1998, pp. 75-89
An equation of state for chain molecules is developed. It uses a hard-
chain reference term based on the theory of Wertheim. Attractive inter
actions are described using a square-well potential with temperature-d
ependent well width. The proposed model accounts for the connectivity
of the chain segments also in the attraction term using the analytical
expression for the radial distribution function at contact for chain
fluids derived by Chiew. For the description of a pure component three
parameters are required: segment number, segment diameter and the squ
are-well potential depth describing the segment-segment interactions.
These parameters were estimated for numerous substances, Vapor pressur
es and Liquid densities of volatile fluids as well as polymer densitie
s can be reproduced with high accuracy. A comparison with the original
SAFT model and the modified GFD theory shows that the proposed equati
on of state can fit the pure-component behavior better than the other
two models. (C) 1998 Elsevier Science B.V. All rights reserved.