of irreversible processes. The unmarked areas are coupling relations that are given by the kinetic theory. Very few of these coupling relations have been studied experimentally.
To calculate the properties of polymer liquid mixtures, one needs to have an expression for the pair distribution function. Very little is known about this quantity. It is needed in order to develop the stress-tensor and heat-flux expressions for mixtures. These are tough problems but to progress they must be attacked and solved.
Now polymers are really a mess.
It's been so for decades, I guess.
But let's not be fearful
Instead let's be cheerful:
'Tis better to "opt" than to "pess."
MTGL: Molecular Theory of Gases and Liquids, by J. O. Hirschfelder, C. F. Curtiss and R. B. Bird, John Wiley and Sons, New York (1954, 1964).
BSL: Transport Phenomena, by R. B. Bird, W. E. Stewart, and E. N. Lightfoot, John Wiley and Sons, New York, 2nd Revised Edition (2007); corrigenda are posted on RBB's web page at U. W.
 J. G. Kirkwood, J. Chem. Phys., 15, 72 (1947); MTGL, §7.1c.
 C. F. Curtiss & J. O. Hirschfelder, J. Chem. Phys., 17, 550
(1949); MTGL, Chapter 7.
C. F. Curtiss & R. B. Bird, Ind. Eng. Chem. Research, 38, 2515 (1999); errata 40, 1791 (2001). See also BSL, p. 768.