  A phantom network of Gaussian chains far from the point of gelation can be
described as a gas of interacting particles represented by the cross links. The
type of particles varies with the network functionality, whereas the type of
interaction depends on the properties of the connecting chains. In a mean field
approximation the Equation of State can be calculated using Mayer's cluster
expansion. The resulting isothermal compressibility is compared for different
cross link functionalities.

Soft Condensed Matter;Statistical Mechanics