Viscosity(1.18)

Thermal conductivity(1.19)

Here m is the molecular mass, is the mass density, and the omegas are functions of , and and are parameters in the inter-molecular force expression. If the omegas are set equal to 1, then the results above are those for a gas of rigid spheres of diameter .

2. POLYMER MIXTURES

This discussion is a summary of a series of publications by Curtiss and Bird during the period 1996 to 1999, in which we tried, as much as possible, to parallel the above discussion for dilute gas mixtures [5]. We visualize a polymer molecule as a collection of mass-points ("beads") connected by some kind of interbead forces ("springs"). The springs may be chosen in several different ways:

Hookean spring:(2.1)

This is a simple linear spring, which can be stretched

indefinitely. It is easy to handle analytically, but gives

generally poor results for describing rheological behavior.

H is a spring constant.