THE CaBER 1 capillary breakup extensional rheometer, designed by the Cambridge Polymer Group and manufactured by Thermo Haake, is the only commercially available rheometer for measuring extensional properties, according to distributor Rheology Solutions .
Many different experimental techniques for measuring the elongational properties of non-Newtonian fluids have been developed over the past 30 years.
All these techniques were difficult to operate, generated complex flows and therefore confusing results. As a consequence successful commercially available instruments did not exist - until the CaBER 1.
Knowledge of the elongational behaviour of fluids is important for both industrial and basic research purposes.
Complex flows that contain strong extensional components occur in many industrial processes and applications. Some examples are extrusion flows, coating flows, contraction flows and fibre spinning flows.
Most materials exhibit very different responses in an extensional flow compared to a shearing flow.
The thinning and breakup of a fluid filament that is analysed with the CaBER instrument provides valuable information about the material's physical properties that rotational rheometers simply can not provide.
The CaBER 1 is suitable for examining adhesives, measurement of tackiness, solvent loss or gain, associating polymers, biomaterials, and surfactants.