Using a parallel plate rheometer equipped with a partitioned plate, and an extensional fixture (SER), a full rheological characterization of several commercial ionomers and their corresponding copolymers has been carried out including the determination of the linear viscoelastic moduli, the damping function and the tensile stress growth coefficient (extensional viscosity). The experimental rheological data have been fitted to a viscoelastic model (K-BKZ). Capillary flow simulations have been carried out to determine the effects of ionic and hydrogen bonding associations on the entry pressure (indication of extensional rheological effects), corner vortex length and strength as well as on the flow patterns formed due to these strong associations.