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Modular torque rheometers
Flexible solutions for advanced material development and quality control of polymers, ceramics, and innovative materials
Flexible characterization during mixing and compounding is essential to meet the ever-changing requirements of end markets, internal changes, and external regulations.
Combining multiple instrument functions in a single system
(e.g., mixing, characterization, etc.) allows you to replicate large-scale production processes at the lab scale. This can save space, materials, and time while you evaluate processes and develop new formulations.
What is a torque rheometer?
A torque rheometer is a highly modular measuring, mixing, and extrusion system for material development, process development, and quality control. Process-relevant material data for product and process development can easily be obtained, including melting behavior, influence of additives, temperature stability, shear stability, melt viscosity, and more.
HAAKE PolyLab Torque Rheometer System
The flexible Thermo Scientific HAAKE PolyLab Torque Rheometer enables a range of material development tasks with just one instrument, saving time and investment costs. Interchangeable processing units can be attached in seconds to the proven drive and measuring unit. Additionally, the entire instrument is controlled by intuitive software.
- Choose between benchtop or movable floor-standing drive and measuring units to serve your specific application needs, from material development to QC of polymers, ceramics, and innovative materials.
- Modular plug-and-play concept switches between different processing devices, such as batch mixers, single screw extruders, or conical/parallel twin-screw compounders.
- Lab-scale measuring devices can work with small sample volumes, saving material cost and time in order to produce and characterize more samples in less time.
- Perform rheological testing solutions under process-relevant conditions. The same system can be used to compound new materials and, with just a few set-up changes, test those same materials for relevant properties.
- A unified software platform across all applications ensures failure-free operation.
- Simulate different production processes with a broad range of downstream equipment.
HAAKE PolyLab RheoDrive Systems
Thermo Scientific HAAKE PolyLab RheoDrive Systems are the basic drive unit for the instrument, available as tabletop and mobile stand-alone versions. They contain all the elements of a torque rheometer that are required to drive the instrument’s measuring systems and to monitor torque during material processing and testing.
Measuring systems for HAAKE PolyLab Torque Rheometers
All measuring systems of the HAAKE PolyLab System can be quickly connected to the RheoDrive System with “plug and measure” functionality, and are equipped with specialized measuring, control, and evaluation technology.
Measuring mixers for HAAKE PolyLab Systems
Thermo Scientific HAAKE PolyLab Rheomix Laboratory Measuring Mixers can help characterize a material’s response to shear energy and temperature in order to describe its melting, degradation, plastification, flow, and curing behavior. They can also be used to produce small batches of new materials.
Extruders for HAAKE PolyLab Systems
Thermo Scientific HAAKE PolyLab Rheomex Laboratory Extruders are available as single, parallel twin-screw, and conical twin-screw extruders for compounding and processing of polymers as well as rheological characterization.
Single-screw extruders for HAAKE PolyLab Systems
Different single-screw extruders are available to serve a broad range of applications from polyolefins to thermoplastics and rubbers. A range of up- and down-stream accessories serve applications such as cast films, blown films, strandlines, or capillary rheology measurements.
Twin Screw Extruders for HAAKE PolyLab Systems
The unique modular design of the Thermo Scientific HAAKE PolyLab Twin-screw Compounder delivers comparable results to its production-scale sibling while offering lab-scale size and requiring only a fraction of the time and material to get results. It has a split-barrel design, where the top half can lift upwards, to easily study new formulations. With a wide range of up- and down-stream accessories, as well as a modular screw design for parallel twin-screws, this torque rheometer set-up is useful for a variety of R&D processes from compounding, to processing, to characterization of new formulations.
Rheological characterization with HAAKE PolyLab Torque Rheometers
HAAKE PolyLab Systems allow for rheological testing under process-relevant conditions. Different capillary dies are available depending on the material to be tested and the desired shear rate range; these enable reliable determination of rheological behavior. This is of prime importance for machine and tool design, as well as the optimization of final products.
Polymer materials and other fluids such as ceramic masses are not generally processed into end products in their purest forms. More often, processing additives, pigments, fillers, and modifiers are added to the original material to give the end-product its desired characteristics. Apart from these additives, the molecular weight and distribution also significantly influence the flow characteristics of the polymer.
Typical tests determine:
- The flow characteristics at differing processing parameters, temperatures, and shear rates
- The influence of functional and processing additives on viscosity
HAAKE PolySoft Software
The Thermo Scientific HAAKE PolySoft Software guides QC with correct system set up and pre-programmed methods accessible with a single button press. The system software is also available in multiple languages for businesses and processes that span multiple countries. It also saves time and reduces operating errors as users only need to learn one software system to perform many different activities.
How to Choose the Right Torque Rheometer for Your Application
Compare the HAAKE PolyLab QC and HAAKE PolyLab OS systems for quality control, formulation development, and polymer process optimization.
| HAAKE PolyLab QC System | HAAKE PolyLab OS System | |
 |
 |
|
| Footprint | Compact Benchtop | Floor standing, movable |
| Max torque | 270 Nm | 300 Nm (RD7) or 400 Nm (RD16) |
| Flexibility to attach different measuring systems | Yes | Yes |
| Mixer | ~60 ccm, 300 ccm | ~60 ccm, 300 ccm |
| Single-screw extruder | L:D 19:25 | Various L:D ratios |
| Twin-screw extruder | Conical screws only | Conical and parallel screws with a segmented screw design |
| Capillary rheometry | Rod, slit (with balance) | Rod, slit (with balance and melt-pump), extensional dies |
| Post-extrusion systems | Range of dies, water bath, pelletizer, various take-off systems | Range of dies, water bath, pelletizer, various take-off systems |
| Application examples | ||
| Mixer test | Best suitable for PVC, rubber | Yes |
| Filter test | Yes | Yes |
| Downstream application example | Cast film, blown film, strandline, capillary rheology | Cast film, blown film, strandline, capillary rheology |
| Material compounding of engineering and high temperature polymers | No | Yes |
| Capillary rheology | Yes, especially for PVC | Automated rheology with parallel twin-screw extruders using a melt pump |
| Conductivity measurements | Yes | Yes |
| Learn more | Learn more | |
Torque rheometer basics and material characterization
A torque rheometer is a device that measures the amount of torque required to mix and process materials under controlled shear, temperature, and speed.
By recording torque over time, it reveals how a polymer or other material melts, fuses, and degrades.
A modular torque rheometer, like the Thermo Scientific HAAKE PolyLab Systems can be connected to interchangeable processing units such as measuring mixers, single-screw extruders, parallel twin-screw and conical twin-screw extruders. The term “modular” means the system can be configured with different processing attachments depending on the application. This flexibility allows users to perform a wide range of polymer processing and quality control experiments using a single drive and control platform.
The system measures parameters such as torque (material resistance to shear), temperature, pressure, speed, and melt behavior over time.
These measurements help characterize multiple aspects of a polymer or other material:
- Melting and degradation behavior
- Plastification
- Curing
- Viscosity
- Flow behavior
- Additive interactions
- Overall processability of polymer materials
A torque rheometer reproduces processing conditions, while rotational and capillary rheometers measure fundamental flow properties. Torque rheometers use mixers or small extruders to simulate compounding, giving direct insight into fusion, plasticization, and stability under realistic shear and temperature loads.
Talking to an application scientist can help identify the best solution for your application.
A torque rheometer can be a cost-effective alternative to pilot-scale polymer processing trials, particularly during formulation development, process optimization, and quality control. By requiring only small sample quantities, it allows researchers to evaluate mixing behavior, melting characteristics, PVC fusion, viscosity, and overall processability before committing materials and resources to larger-scale testing.
Early identification of formulation or processing issues can help reduce material waste, support more efficient formulation development, and identify potential processing issues before scale-up. In addition, modular systems such as the Thermo Scientific HAAKE PolyLab platform are flexible and can be used with measuring mixers or laboratory extruders to perform rheological tests as needed. This allows laboratories to support multiple applications with a single investment.
Measuring mixers for polymer development and quality control
Measuring mixers are used to evaluate how polymer materials respond to shear energy and temperature during processing. They are especially valuable for characterizing melting behavior, plastification, flow properties, curing behavior, and thermal or mechanical degradation before scaling up to extrusion or production processes.
These systems are ideal for small-batch material development, formulation screening, and quality control when only limited sample quantities are available. Measuring mixers can also produce small batches of new materials for further testing and downstream processing.
When combined with a single-screw extruder and appropriate dies, measuring mixers enable the production of prototype final products such as sheets, films, and thin fibers. This supports efficient material and process development on a laboratory scale.
Additives and fillers can significantly affect polymer viscosity, flow behavior, thermal stability, curing, and mechanical performance. Measuring mixers and extruders help quantify these effects during formulation development and quality control.
Mixer testing and rheogram interpretation
A mixer test is a laboratory method used to evaluate how a material behaves under controlled shear and temperature conditions during mixing. A typical mixer test is performed at a defined rotor speed (shear rate), while the material’s response is continuously recorded as torque over time. During the test, the material is placed inside a temperature-controlled mixing chamber equipped with rotating mixer blades or rotors. As the material melts, plastifies, cures, or degrades, its resistance to the applied shear changes. These changes are measured as torque and displayed together with melt temperature in a graph called a rheogram. The rheogram (torque and melt temperature versus time at constant speed) is characteristic for different materials and formulations and can therefore serve as a “fingerprint” for quality control. Mixer tests are commonly used to investigate any of several material behaviors:
• Melting and degradation behavior of polymers
• Gelation and plastification of PVC dry blends
• Curing behavior of thermosets
• Mastication and vulcanization of elastomers
• Effects of fillers, pigments, lubricants, and additives
• Viscosity changes caused by nanoparticles or other additives
Discover how a mixer test experiment is set up and data are analyzed
A mixer rheogram records torque and melt temperature versus time during mixing at a constant shear rate. It serves as a material fingerprint for quality control and helps identify structural changes and processing behavior in polymer blends.
Achieving reproducible mixer test results requires consistent testing conditions, including rotor speed, sample weight, mixer temperature, and sample handling procedures. Even small variations in these parameters can significantly affect fusion time and measured material behavior. When tests are performed under controlled and standardized conditions, mixer testing becomes a highly sensitive tool for detecting formulation changes, evaluating raw materials, and supporting quality control.
PVC fusion, thermal stability, and processing performance
A laboratory mixer test evaluates PVC fusion behavior by measuring torque as a function of time under controlled temperature and shear conditions. The resulting rheogram identifies key processing parameters such as fusion time, fusion maximum, and melt viscosity, helping optimize formulations and processing conditions.
Thermal stability can be assessed using a torque rheometer by monitoring the onset of degradation during a mixer test. The time between a period of stable processing and the onset of degradation provides a relative measure of a compound's resistance to thermal degradation during processing.
Even small changes in stabilizer concentration can significantly influence PVC fusion behavior and thermal stability. Mixer tests can detect these differences by measuring fusion time, stable processing time, and degradation onset, helping optimize formulations before production.
A laboratory mixer test can simulate PVC processing under controlled shear and temperature conditions. By analyzing the mixer rheogram, scientists can evaluate melting behavior, fusion characteristics, melt viscosity, and degradation tendencies before running production trials.
By comparing mixer rheograms, scientists can evaluate differences in fusion time, melt viscosity, thermal stability, and degradation behavior caused by formulation changes, additives, fillers, or raw material variations.
Fusion behavior directly influences the degree of gelation in PVC compounds. Improper fusion can affect mechanical properties, impact resistance, alter weldability, and influence overall product quality in applications such as pipes, profiles, and window frames.
The steady-state torque region of a mixer rheogram provides a relative measure of melt viscosity. For absolute viscosity measurements, a laboratory extruder equipped with capillary dies can determine viscosity as a function of shear rate.
Extrusion analysis, flow behavior, and capillary rheology
Extruder capillary rheology can generate viscosity curves over a range of shear rates. These data can be fitted to rheological models such as the Carreau model or the Ostwald-de Waele model and used as input for simulation software.
Online capillary rheology measures polymer shear viscosity during extrusion using slit or capillary dies. Shear stress is calculated from pressure drop, while shear rate is determined from the extrudate flow rate.
Polymer extrusion behavior can be analyzed by monitoring torque, melt temperature, pressure, throughput, and shear viscosity during extrusion. Laboratory extruders also enable rheological measurements using slit or capillary dies.
For Research Use Only. Not for use in diagnostic procedures.