Instrument

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Rheometry quantifies the flow patterns of non-Newtonian liquids by measuring their material functions that depend on shear rate, frequency, time and so on. Steady shear flow tests are used to measure the viscometric functions (steady shear viscosity, primary and secondary normal stress coefficients). Unsteady unidirectional shear flow tests are used to measure the time -dependent viscoelastic functions (transient shear viscosity, relaxation modulus, storage modulus, loss modulus, steady-state creep compliance). The rheological properties of liquids determine their mobility and are significant for abundant applications: polymer processing, enhanced oil recovery by polymer flooding, transportation of waxy crude oils, oil-well drilling, spreading of organic pollutants in subsurface, practical uses of foods (e.g. mayonnaise, milk, ketchup, yogurt, chocolate, etc), coating, printing, etc.

Characteristics

Rheometry quantifies the flow patterns of non-Newtonian liquids by measuring their material functions that depend on shear rate, frequency, time and so on. Steady shear flow tests are used to measure the viscometric functions (steady shear viscosity, primary and secondary normal stress coefficients). Unsteady unidirectional shear flow tests are used to measure the time -dependent viscoelastic functions (transient shear viscosity, relaxation modulus, storage modulus, loss modulus, steady-state creep compliance). The rheological properties of liquids determine their mobility and are significant for abundant applications: polymer processing, enhanced oil recovery by polymer flooding, transportation of waxy crude oils, oil-well drilling, spreading of organic pollutants in subsurface, practical uses of foods (e.g. mayonnaise, milk, ketchup, yogurt, chocolate, etc), coating, printing, etc.

Services

eModel: Dynamic Stress Rheometer SR-200 (Rheometric Scientific)
Controlled stress rheometer.
The shear stress is related with the torque generated by an electromagnet, whereas the shear rate is related with the angular velocity measured by an optical encoder.
Torque range: 0.001 – 20 mN m,
Rotational rate: 0-100 rad/s,
Angular resolution: 4.2 μrad,
Frequency range: 10-5 – 500 rad/s, Temperature range: 0-95oC.
Controlled stress dynamic test modes: frequency sweep, single point, stress sweep, temperature ramp, temperature sweep, time sweep.
Controlled stress steady and transient test modes: shear rate sweep, step shear rate, step stress (creep-recovery), stress ramp, stress sweep.

Sample Properties

Liquid volume per test: ~ 1 ml
Couette (concentric cylinders) geometry for liquids of low viscosity and suspensions of low stability.
Cone-and-plate geometry for liquids and melts of relatively high viscosity.
Parallel plate geometry for liquids and melts of relatively high viscosity