Configurational and rheological properties of cyclic polymers

Abstract

The configurational and rheological properties of multiple-twisted ring polymers, modelled as long cyclic finitely extensible bead–spring chains with internal distance constraints, have been calculated. This model corresponds to chemically cross-linked Rouse chains. The calculations were carried out for equilibrium and steady shear flow. The mean-square radius of gyration in equilibrium depends on the number of loops. In shear flow, non-Newtonian flow behaviour arises. The shear viscosity and the first normal stress coefficient decrease with increasing shear rate. The second normal stress coefficient is negative and much smaller than the first normal stress coefficient. Since the mean-square radius of gyration, shear viscosity and the first and second normal stress coefficients depend on the number of loops, the latter can be determined by four independent experiments.