29 mars 2011
Instrument Specifications :
|Instrument :||Strain-controlled Rheometer|
|Make :||TA instruments|
|Model :||ARES-RFS (Rheometrics Fluid Spectrometer)|
|Localization :||Building : 11, Floor : 1, Room : 137|
|Phone :||(33) 4 67 14 35 88|
|Status :||L2C , Dpt. CVN, soft matter group. Scientific collaborations involving the device are possible.|
|Scientific Responsible :||Serge Mora|
|Technical Responsible :||Jean Marc Fromental|
This strain-controlled rheometer can be used to test samples for both oscillatory (dynamic mode) and steady (steady mode) shear measurements in three test fixture geometries : parallel plate, cone and plate and concentric cylinders (Couette). Concentric cylinders are especially useful for very low viscosity fluids, dispersions of limited stability, and for applications where fluid/solvent evaporation may be a concern.
Deformation : In the dynamic mode, the motor begins all tests at the motor zero position, and drives symmetrically about motor zero to the strain commanded by the software. The maximum angular deflection of the motor is 0.5 rad. The minimum deflection is 5 μrad. The angular frequency ranges from 10-5 to 200 rad/s. In the steady mode, the motor can begin a test from any position, rotating clockwise or counterclockwise as specified by the software. The angular speed ranges from 10-3 to 100 rad/s.
Torque measurement : The rheometer is equipped with a torque captor from 0.2 μN.m to 100 N.m, and with a normal force sensor from 0,01 to 20 N.
Geometries : This apparatus is fitted with steel, titanium or plexiglass geometries, smooth or rough :
Temperature control : Sample temperature can be controlled within a large range :
The ARES-RFS provides rapid response and extremely accurate strain resolution. These are essential for accurate determination of critical strains in structured fluids, stress relaxation studies, and the characterization of non linear rheological behaviour. The ARES-RFS air-lubricated, Force Rebalance Transducer combines high linearity, sensitivity, and stability with a five-decade range. This allows you to characterize materials over a broad viscosity range without having to change transducers. The ARES-RFS is also ideal for testing lower viscosity materials ; even materials with viscosities comparable to water.
(Optical) diagram (s) (to be completed)
|Applications||Fluids, melts, Medium or high viscosity samples||Fluids, melts Medium or high viscosity samples||Fluids, melts Medium or low viscosity samples|
|Sample volume (cm3)||0.14 or 0.65||variable||8|
|Min/Max strain (%)||0.25 / 2500||-||0.088 / 875|
|Min/Max shear rate (s-1)||0.05 / 5000||0.0175 / 1750|
|Min/Max stress (Pa)||0.004/9500||0.004/9500||0.004/2000|
|Temperature control||Fluid bath or Peltier plate -30°C /150°C||Fluid bath or Peltier plate -30°C /150°C||Fluid bath -10°C /150°C|
|Advantages|| * Homogeneous shear
* Small sample volume
* Normal force measurements
* Easy handling
* Variable sample thickness
* Shear rate limits adjustable by changing gap
| * Easy handling |
* Large surface area
* High shear rate available
|Disadvantages|| * Highly sensitive to correct positioning (gap) of cone and plate
* Sample preparation for high viscosity samples difficult
|* Shear rate not constant|| * Large sample volume |
* Possible shear history effects from loading
Macosko, C.W. Rheology : principles , measurements and application, Weley-vch, 1994.