RHEOGRAPH Add-On

With the RHEOGRAPH, we offer a flexible platform for the characterization of polymers. The capillary rheometer serves as a basic istrument to which various additional add-ons can be added on a modular basis.

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Modular and flexible

Extend your capillary rheometer

The RHEOGRAPH can be optimally adapted to the individual requirements of each application. In the full configuration, the processing behaviour can be comprehensively characterized.

The basic GÖTTFERT capillary rheometer is designed to carry out viscosity measurements with plastics, rubbers and other materials.

Modular add-ons offer additional options for the characterization of materials.

Success Story: Our testing instruments in use

Roundtable: Know-how directly from our lab

NORMAL STRESS DIE

Measuring first normal stress difference at high shear rates via capillary rheometer.

Determination of Normal Stress at high shear rates and closer to the processing shear rates which was not possible with conventional technique
Detection of flow instabilities at processing shear rates
Measurement of Viscosity, elongation viscosity and Normal Stress differences

SHARK SKIN

The Shark Skin measuring head is mounted at the bottom of the test barrel instead of the capillary. With this option it is possible to measure exactly at which critical shear rates surface inhomogeneities occur.

Detection of the Shark Skin effect
Consisting of slit die, three high frequency pressure-sensors (sampling rate up to 20 kHZ), as well as software package
Determination of the frequency spectrum and statistical evaluation of the pressure signal
Optimization in the extrusion, film and coating process

THERMAL CONDUCTIVITY

The sensor for thermal conductivity is mounted just like a standard piston. The barrel is closed at the bottom during the test. The thermal conductivity measurement of solids or melt is performed under stationary conditions.

Determination of the thermal conductivity at a measuring range up to 450°C and 1000 bar
Developed according to ASTM D5930
Test sensor with integrated heating element and temperature sensor
Process-Simulation and optimization of cycle times in injection molding
No mechanical modifications necessary
Fully automatic measurement

CONTIFEED

The CONTIFEED is a mini-extruder which directly feeds the test barrel of a capillary rheometer. This add-on is particularly suitable for thermally unstable material, due to the reduced dwell time. The plasticizing with pre-shearing in the extruder, makes the measuring process very similar to the production process.

The advantages of the CONTIFEED:

Automated, bubble-free filling of the test barrel
Influence of plasticizing via extruder can be investigated
Shorter material dwell time under temperature influence
Rheological characterization at conditions similar to the production process
Pre-plastification also allows the measurement of powder materials (e.g. PVC dry blends)

PVT (ISOTHERMAL/ISOBARIC)

Besides the PVT 500, GÖTTFERT also offers the PVT-measurement as an add-on for the capillary rheometer. The measurement characterizes the material specific dependencies between pressure, specific volume and temperature.

Isothermal or isobaric measurements according to ISO 17744
Constant high cooling rate with newly developed air cooling or thermostat
Fully automated measurement
Automatically generated PVT diagram
Parameterization with Tait model as interface to simulation software

Principle of pVT measurement (isothermal)

Principle of pVT measurement (isobaric)

RHEOTENS

The drawability of polymer melts is of utmost importance in many processes of plastics production and processing.

The patented RHEOTENS method has proven to be an extremely sensitive measuring principle that delivers highly reproducible results to show even minimal batch fluctuations.

In addition to the already existing constant speed and constant acceleration, exponential acceleration is now also possible. The determination of the extensional viscosity function according to Prof. Wagner is an integral part of the RHEOTHENS.

The RHEOTENS is well suited as a processability test for materials used in extrusion or film applications.

HAUL-OFF

Our newly developed HAUL-OFF with a maximum speed of 2000 m/min is particularly suited for the characterization of fibre-grade materials. The system can be operated with constant acceleration or at constant speed steps. The pull-down force is measured via a smooth-running, anti-stick coated measuring wheel on a highly sensitive force transducer.

DIE SWELL MEASUREMENT

The measuring head is mounted below the die. The measurement can be carried out parallel to a viscosity measurement.

Determination of the dynamic and static die swell
Evaluation of a die swell profile (BASELL method)
Swivel arm with continuous height adjustment
Laser measuring head in 0.1 μm or 7 μm version
Optional with automatic melt cutting device
Optional: acquisition of two strings simultaneously
Application: Simulation of material swelling behaviour during extrusion

COUNTER PRESSURE CHAMBER

The viscosity of polymers can also depend on the general pressure level. The Counter Pressure Chamber is mounted behind the die and generates a back-pressure at the die outlet, which is measured with an additional pressure sensor.

Determining the pressure dependence of viscosity (pressure coefficient)
Determination of the critical wall shear stress for wall slip
Maximum pressure (Pm) 1200 bar
Temperature range up to 400°C
Optimization of the flow processes in processing machines (injection molding and extrusion tools with long flow paths, melt pumps)