Rheology

Smithers Rapra offers a wide range of rheological services to satisfy all needs ranging from long/short term routine quality control to process design & flow analysis. The measurement of rheological properties can help to develop an improved product, predict its end use performance & the physical properties of a product during & after processing. A range of Rheometers are available for the analysis of both plastics & rubbers.

Smithers Rapra regularly provides a Rheology service to support quality control processes, assist with failure analysis & process optimisation issues. The information obtained can provide accurate materials property data for flow simulation software packages such as Moldflow & Sigmasoft 3D.

Rheology for plastics

Perhaps uniquely, Smithers Rapra offers the possibilities to generate Rheological data all the way through from simple Melt Flow Index (MFI), to low shear rate, high shear rate & finally, to in-line die Rheology on an extruder.

Melt Flow Index/Rate (MFI/MFR)

• Typically used as a basic quality control tool.
• Useful for checking whether the polymer grade is as specified, especially if processing problems are occurring.

Rotational Rheometry

• Oscillating disc Rheometry is a more powerful technique than MFI.
• It can provide information on molecular weight distribution that can be used for processing, thermal stability or degradation studies.
• Rotational Rheometry is also used for the assessment of changes in viscosity as a function of temperature or shear rate.

Capillary Rheometry

• Measures viscosity at shear rates typical of those used in polymer processing, such as extrusion or injection moulding.
• Can show the difference between polymers with similar MFI’s but different molecular weight distributions.
• Measures viscosity at a range of temperatures to help optimise processing conditions.

In-line Rheometers

• Smithers Rapra have die Rheometers for measuring viscosity under actual processing conditions.
• We can equip a range of single screw extruders to run your product.
• Useful for assessing the effect of additives on processing.

Rheology for rubbers

The service for rubbers covers simple cure characteristics & the more sophisticated rubber processing analysis.

Cure properties (MDR)

• This instrument is in almost constant use in our processing lab. It is used to assess cure kinetics & offer a quality control solution.
• Variable temperature cure analysis.
• Can also be used for assessing cross-linkable polymers as well as rubbers.

Rubber Processing Analysis (RPA)

• More sophisticated than MDR.
• Can be used to assess the processing of rubbers in a similar way to oscillating disc Rheometers for plastics. Provides information useful for extruding rubber compounds.

Can also be used for assessing polymers such as PVC.