Syringe-based capillary rheometry of dense pastes a method for viscosity measurements and processability characterizations

Capillary rheometry is a central tenet of loaded polymer system characterization, serving as the instrument of choice for viscosity measurement when designing materials for extrusion processes. However, as materials get increasingly solids loaded, beyond 50vol%, traditional capillary rheometry instruments and procedures no longer suffice. In this report a disposable, syringe-based capillary rheometer for dense pastes is proposed that achieves accurate viscosity measurements of reference materials, within 6%, and matches process viscosity measurements within 10%. It is shown that this new test instrument can be used to characterize material flow curves and accurately predict the processability of dense paste materials in progressive cavity pumps, eliminating waste accrued from trial and error. This advancement opens a new space for characterizing highly loaded suspensions in a standardized, controlled manner and paves the way for in-situ control developments moving forward.