Effect of ring closure on rheological behavior (Q1094222)

A comparison is given between the rheological behavior of dilute solutions of linear polymers and ring-shaped polymers. Both types of molecules are modeled as freely jointed bead-spring structures, with Hookean springs. It is shown that the ring closure results in lowering the viscosity by a factor of two regardless of the number of beads, N. The first normal stress coefficient is lowered by a factor between 5 (for \(N=3)\) and 8 (for \(N\to \infty)\). The form of the constitutive equation for rings is the same as that for chains, but the spectrum of relaxation times is altered. Formal expressions are obtained for the ring configurational distribution function and the single link distribution function for an arbitrary time-dependent homogeneous flow.