This paper discusses shear viscosity measurements of polymer melts by the capillary rheometer. Particular emphasis is placed on investigating the effects of viscous heating and pressure dependence of viscosity in capillary flows. The capillary flow problem is addressed by means of numerical simulation using the finite element method to solve the equations of continuity, momentum and energy alon...

A precision-machined cross-slot flow geometry with a shape that has been optimized by numerical simulation of the fluid kinematics is fabricated and used to measure the extensional viscosity of a dilute polymer solution. Full-field birefringence microscopy is used to monitor the evolution and growth of macromolecular anisotropy along the stagnation point streamline, and we observe the formation...

A filament stretching extensional rheometer and capillary breakup extensional rheometer are used to measure the extensional rheology of a series of wormlike micelle solutions experiencing a uniaxial elongational flow. The experiments are performed using a series of wormlike micelle solutions of both cetylpyridinium chloride and sodium salicylate NaSal in an aqueous sodium chloride solution and ...

Attractive emulsions near the colloidal glass transition are investigated by rheometry and optical microscopy under shear. We find that (i) the apparent viscosity eta drops with increasing shear rate, then remains approximately constant in a range of shear rates, then continues to decay; (ii) the first normal stress difference N1 transitions sharply from nearly zero to negative in the region of...

Nowadays, finely controlling the mechanical properties of polymeric materials is possible by incorporating supramolecular motifs into their architecture. In this context, the synthesis of a side-chain terpyridine-functionalized poly(2-(dimethylamino)ethyl methacrylate) is reported via reversible addition-fragmentation chain transfer polymerization. By addition of transition metal ions, concentr...

The shear response of a model polymer–clay gel is measured using small-angle neutron and light scattering, optical microscopy, and rheometry. As the flow disrupts the transient network that forms between clay and polymer, coupling between composition and stress leads to the formation of a macroscopic domain pattern, while the clay platelets orient with their surface normal parallel to the direc...