Analysis of a wide range of fluids and solids using rheological techniques undertaken by our experts
Rheology research laboratories test polymeric materials for rheological properties. Rheological characterisation of materials includes polymers, liquids, adhesives and other samples using a wide range of shear and extensional conditions. Intertek rheology labs determine rheology properties for degradation studies, determining molding parameters, materials performance, and other applications.
Understanding the rheological (flow) properties of a polymer helps obtain optimized material properties during the molding process. Rheology testing can determine if materials are processed properly with minimal product degradation. Rheological tests to measure the viscosity of a polymer ranging from single point tests to variable shear-rate tests.
Rheological characterisation can be accomplished using a wide range of shear, tensile, and extensional conditions. This data can be used for many purposes including: quality assurance, product development, and to better understand material performance. In addition, rheology testing can determine if materials are processed properly with minimal product degradation or to understand the flow properties that are critical in QA molding application.
Fluids analyzed include
- Polymer melts
Fluid Rheology tests are performed while the polymer is in the melt phase or while the polymer has been dissolved in a solvent for Intrinsic Viscosity and Relative Viscosity.
Solids analyzed include
- Polymer plaques
- Molded articles
Rheological tests can measure the viscosity of a polymer ranging from single point tests to variable shear-rate tests.
Rheology tests include
- Frequency sweeps
- Temperature ramps
- Intrinsic viscosity and relative viscosity
- Melt flow rate (MFR) and Melt Flow Index (MFI)
- Capillary rheometry
- Creep (flow under a given force or stress)
- Stress relaxation (change in force for a given deformation)
- Thermal stability
- Melt viscosity
Many of these techniques fall under the umbrella of Dynamic Mechanical Analysis (DMA). These DMA tests often provide a mechanical fingerprint for a material. Properties such as Tg, the breadth of Tg, secondary transitions, crosslink density, and many others can be determined using DMA.
Contact our experts to discuss the most relevant way to use rheology for your application. Ultimately, possessing a better understanding about your material’s properties will enable you to proceed towards the creation of a product with improved performance.
Intertek’s rheology laboratories are located in Europe and North America. We have the ability to ship samples to our labs from most customer locations.
Two major rheological analysis methods are available for the characterisation of creams/pastes and semi-solids, such as Controlled Stress Rheology (Rheometrics SR500) to predict properties such as shelf life/ease of application and stability - sedimentation rate - performed over a variety of test temperatures) and Controlled Strain Rate Rheology (Rheometrics ARES, RDAII).
We also provide Dynamic oscillatory rheology can also be performed which provides much more information on the microscopic structure of viscoelastic materials (such as creams and pastes) as well as further tests to determine the limit of the linear viscoelastic response, dispersion quality and also material thixotropy, elasticity and stiffness values.
Hyaluronic acid (HA) gels are used by dermatologists and cosmetic surgeons as dermal fillers, which when injected into the skin, can ‘lift’ wrinkles and improve facial appearance. The different processes used in their manufacture and formulation yield products with unique physical characteristics that play an important role in predicting their clinical performance and lifetime of benefit perceived by the patient.
Understanding the relationship between the particle size and particle size distribution of crosslinked HA gels with the viscoelastic behaviour of the gels themselves can help manufacturers develop unique property/microstructure relationships that can help clinicians in achieving desired results for a variety of patient needs.
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