Torque Rheometers Bring Advantages in Polymer Development

In this interview, AZoM talks to Dirk Leister from Thermo Fisher Scientific about the role of torque rheometers in the field of polymer compound development.

To start, could you give a brief overview of Thermo Fisher Scientific and the role that you play in the field of polymers?

Our company, Thermo Fisher Scientific, is a global leader in serving science. I work in the business that delivers twin-screw compounders, torque and rotational rheometer solutions to the polymer

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industry to optimize new processes and material development.

Rheology and compounding are particularly important in the field of new polymeric materials. Our customers are working every day to make life better in packaging materials, aerospace and automotive components, cosmetics and healthcare products, and almost every other area of daily life by developing new polymer compounds with specific properties. We provide them with the systems to do that.

R&D customers in the sectors of novel polymer compounds or polymer additives are often limited by the amount of material available to develop formulations or do pilot-scale production. Our standalone twin-screw compounders offer flexible compounding configurations for small sample amounts making them particularly well-suited for R&D work. They are also available in different grades of steel for the product contact parts so they can be used in more regulated environments such as pharmaceuticals, cosmetics and food applications.

Our rheometer solutions help to characterize polymer compounds in a melt or in their final shape to optimize processing or ensure quality requirements.

One instrument in particular, the Thermo Scientific™ HAAKE™ PolyLab™ Torque Rheometer combines both worlds of compounding and rheological material testing in one instrument. That’s why it’s like a hidden gem for polymer development and processing; just this one instrument serves many needs in both R&D and QC.

What types of work/applications are done in new polymer compound/material development?

It’s amazing what our customers are doing today and working to accomplish for tomorrow with polymers. They are trying to make polymers and products so they are safer, more economical, more lightweight, more heat resistant, longer lasting, and much, much more.

For example, some recent work went into the area of “green tires” to increase fuel efficiency for automobiles. The goal was to develop new rubber compounds from ecologically friendly resources with the aim to reduce roll-resistance and wear; the reduction in resistance helps save fuel and make the tires themselves last longer.

Another hot research topic involves novel battery technologies for electric cars. The focus here is on battery separator films and electrode materials. Both critical battery components can be manufactured using a twin-screw extruder. The lab-scale size of our equipment makes production of those materials fast and resource efficient.

In both examples, it’s important that the new materials are thoroughly compounded at the start. Then, after compounding, extensive testing of the material properties is required. This is where the unique modularity of the HAAKE PolyLab Torque Rheometer comes into play; it can handle both kinds of tasks.

How does the HAAKE PolyLab Torque Rheometer assist in the development of new compound materials?

Our customer’s daily work in polymer development is to create and test a large number of new polymer formulations to find the optimal material properties. But daily work changes and evolves over time. Having a modular system really helps to keep up with not only today’s tasks but future demands as well.

As I said before, the HAAKE Polylab Torque Rheometer blends the worlds of compounding and rheological material testing into one instrument. That’s how the platform can serve multiple research and quality control tasks. The modular design allows it to combine four instrument capabilities in one system solution.

The HAAKE PolyLab Torque Rheometer has a strong, reliable drive and measuring unit, and it's flexible enough to combine with different processing devices. These are batch mixers, single screw extruders, twin-screw compounders, and rheological testing solutions under process-relevant conditions. That means the same system can be used to compound new materials and, with just a few set-up changes, test those same new materials for relevant material properties.

This flexibility helps customers to establish workflows specific to their needs and to rapidly adapt to changing requirements in the future. By utilizing different modules, customers can leverage their workflows in both R&D and QC environments. For example, the batch mixers can be used for recipe development in R&D and quality determinations in QC. The mixers also help to understand important material properties like melting, degradation and flow behavior to optimize final products. Single screw extruders can be used to produce test-specimen like sheets and films to test additive dispersion in a final product.

The HAAKE PolyLab Torque Rheometer system’s continuously operating twin-screw compounder is a lab-scale instrument that delivers results comparable to its production sibling, but the customer needs only a fraction of the material and time to achieve results. With a wide range of up- and downstream accessories and a modular screw design, this torque rheometer is a very useful tool in R&D.

The last, but not least of the four applications is 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 allow the customer to reliably determine rheological behavior. This is of prime importance for machine and tool design, as well as for the optimization of final product.

What’s the real benefit of your torque rheometer system for the user?

The single biggest benefit of the HAAKE PolyLab Torque Rheometer is its modularity which helps users successfully produce and characterize a large number of samples in a minimal amount of time.

For example, the HAAKE PolyLab Torque Rheometer saves time and reduces operating errors as users learn just one software system to perform many different activities. That makes it faster and easier for users to learn how to use the software and do the different tasks. It also reduces the chance for error by not having to operate different software packages for standalone mixers, extruders and rheometers.

Often software methods developed in the R&D lab are complex and involve multiple steps until a full compounding or mixer test is conducted. The HAAKE PolyLab Torque Rheometer provides consistency from R&D to QC with a mode of software operation that guides users in QC to set up the system correctly and run pre-programmed methods by pressing a single button. The software system is also available in multiple languages for businesses and processes that span location sites in multiple countries.

Another way the HAAKE PolyLab Torque Rheometer saves time is through its ability to work with small sample volumes. It not only saves on material costs, but also allows the customer to produce and characterize more samples in less time.

The flexibility of the HAAKE PolyLab Torque Rheometer shows through when it comes to transferring work from the lab to the production environment. With an extremely broad range of available downstream equipment, such as feeders for liquid and solid materials, dies and take-off devices, users can set up entire compounding lines in the lab that have the same functionality as real-world production environments. Because the HAAKE PolyLab Torque Rheometer allows users to do all work under the conditions of the process environment, the results obtained initially allow for easy scale-up to the production area. In fact, the HAAKE PolyLab Torque Rheometer provides data from the analysis of material properties that can be used directly for quality control purposes.

And of course, the HAAKE PolyLab Torque Rheometer is an open system – different sensors can be attached to it to get additional information. For example, conductivity measurements in the mixer can help to analyze the dispersion of carbon black in rubber compounds in an online process. Plug-and-play functionality means the system automatically detects attached accessories and helps to minimize set-up errors. So it’s faster to do multiple applications on one instrument, and the changeover from one application to the next is quick and easy.

In what other applications can the HAAKE PolyLab Torque Rheometer be used?

The HAAKE Polylab Torque Rheometer has applications in many different fields including extensions of the polymers industry itself. More and more customers are deviating from standard polymers to those modified for different applications.

Powder injection molding (PIM) is one field where the HAAKE PolyLab Torque Rheometer is deployed frequently. For PIM feedstock, polymers are compounded with a high load of metal or ceramic powders (80% or more). The HAAKE PolyLab Torque Rheometer enables efficient compounding of those materials.

Additive manufacturing, which includes 3D printing, makes up another field where we have seen a steep rise in interest for specialized material in the form of polymer filament to be used with 3D printers.

Many customers have asked to explore possibilities with the HAAKE PolyLab Torque Rheometer beyond polymers. For example, we are working with industry partners and universities in the areas of food extrusion and cosmetics formulation where the system is used as a continuous mixing device.

Such demand encourages us to continue developing the capabilities of the HAAKE PolyLab Torque Rheometer; we’re always developing new accessories and enhancements to ensure the system can meet future market demands. In fact, we just published an application compendium that shows many specific applications for the HAAKE PolyLab Torque Rheometer; it can be found on our website and even on your AZO Materials web pages. It’s called Flexible solutions for advanced material development.

Download the Free Compendium on Flexible Solutions for Advanced Material Development

We plan to grow the capabilities of the flexible torque rheometer system. There are many new applications to come for the HAAKE Polylab Torque Rheometer. As an open system, we may develop different sensors to provide users with additional information during operation. For example, simultaneous conductivity measurements while compounding new rubber compounds would give users a quality measurement of the homogeneity of the rubber compound.What are the plans for the future of torque rheometers and related polymer instruments at Thermo Fisher Scientific?

We’re always striving to increase the range of our equipment. As another example, additional die designs can help in setting up a small-scale production system to more effectively mimic a large-scale system. And those are just a few ideas of what can be done with the HAAKE PolyLab Torque Rheometer.

About Dirk Leister

Dirk Leister holds an Engineering degree (Dipl.-Ing.) in Biotechnology from University of Applied Science in Giessen, Germany. He also has a bachelor’s degree in Sales and Marketing from the University of Applied Science in Karlsruhe, Germany.

Dirk has over 20 years of experience in Sales and Marketing for laboratory and manufacturing equipment especially in the pharmaceutical and life sciences industries.