Ed. Nikitin et Pa. Paylov, Van der Waals chain-molecule fluid in self-consistent field approximation:Some thermal properties, HIGH TEMP, 38(5), 2000, pp. 690-697
The van der Waals equation for a monomer is used to derive the equation of
state for a fluid consisting of chain molecules of equal length. The evolut
ion of a part of the diagram of state pertaining to liquid-vapor equilibriu
m is treated for the case of an increase in the number of links in a molecu
le. The dependences on the number of links n are found for the following pr
operties of polymer fluid: the critical temperature T-c, the critical press
ure p(c), the critical density rho (c), the critical compressibility z(c),
the temperature of normal boiling, the Riedel parameter of similarity alpha
, the acentric factor omega, and the enthalpy of vapor formation DeltaH(v).
A comparison with the experimental data for n-alkanes and l-alkanols revea
ls that the obtained dependences reflect qualitatively correctly the variat
ion of the above-identified properties with an increase of the number of li
nks in a molecule. For long chains (n much greater than 1), the scaling dep
endences are determined for the properties of a chain-molecule fluid: T-c s
imilar to 1 - n(-1/2), p(c) similar to n(-3/2), rho (c) similar to n(-1/2),
z(c) similar to n(-1), alpha similar to n, omega similar to n(2/3), DeltaH
(v) similar to n.