Melt Viscosity Testing
EMMOUNT Technologies offers capillary rheology testing of molten polymers for use in polymer processing design, troubleshooting and simulation.
This data is personally measured by Dr. Mount and is of high quality and usefulness.
A typical summary report can be downloaded from the download page of this web site and reviewed.
The rheology lab is comprised of an Instron capillary rheometer with a 1 to 2000 Kg load measurement capability and temperatures of from 35 °C up to 400 °C. The Rheometer may be used with a selection of capillaries from 0.03 to 0.06 in diameter and from 2 to 3 inches in length. In addition, three gear rate ranges, used in combination with various capillary diameters, permit the viscosity measurements over a wide range of potential shear rates. Typical data sets are measured at 7 shear rates (Approximately 1 to 3000 sec-1) and three melt temperatures, typically spaced at 200°C to 250°C intervals.
EMMOUNT Technologies Melt Rheology Corner
Data is curve fit to temperature (T) and shear rate (SR):
A melt density may also be measured from a timed and weighed sample of extrudate from the rheometer.
Currently data generated by EMMOUNT Technologies is used for commercial die and screw designs, for the study of blend components impact on viscosity and for the evaluation and trouble shooting of coextrusion instabilities in film and sheet extrusion.
Two sample drying ovens, one ambient and one vacuum oven for drying moisture sensitive resins such as PET, PLA, Nylon, PC etc as well as filled polymers, cellulosic and acrylic polymers such as PMMA prior to measurement.
Viscosity Comparison of two resins at three temperatures using curve fit data at 230°C, 250°C and 270°C.
Samples can be in the form of pellets, powders, liquids, gels or reground film or sheet. Other sample forms, such as finished products, tubing, etc. can be tested by cutting. Hot melt adhesives can be melted and shaped for rheometer introduction.
Pricing is available on request and approximately 1 kg (2 lbs) of sample is necessary to comfortably complete the testing
Melting Rate and COF Measurements using the Screw Simulator
The "Screw Simulator" was designed and build by Professor Chan I Chung for use in experimental studies for the improved understanding of solids conveying and melting in single screw extruders. The information and improved understanding of the extrusion mechanisms studied is used for improving extruder performance and screw design. It represents an extruder turned inside out with the heated roll representing the extruder barrel surface.
Dr. Mount received his PhD by performing an experimental and theoretical study of the melting rate of 7 polymers using the Screw Simulator. Over the years, several other of Professor Chung's students received PhD and masters degrees for studies of the coefficient of friction (COF) and melting rates of polymers. Professor Chung has successfully used the data and melting models developed for scientific screw designs.
Today the Screw Simulator is housed at EMMOUNT Technologies and is available for use in measuring the melting rate of polymers as well as the shear stress in melting and the frictional forces and COF of a solid polymer against a hot moving metal surface. This data is valuable for the use in screw design and scale up as well as for trouble shooting feeding and melting problems of existing screw designs and developing computer simulations of single screw extruders.
Screw Simulator
Many new materials exist today and an improved understanding of the materials frictional and melting behavior in the feed and transition sections of an extruder will help in establishing improved screw designs and melt system performance.
Schematic of the screw simulator showing the sample cell, the rotating melting surface and load cell for stress measurements during melting and friction studies. This device simulates the actions of single screw extruder by forcing a polymer against a hot moving metal surface.
Typical example of the COF behavior of a LDPE as measured with the Screw Simulator
Schematic diagram of the melting (plasticating) rate measurements obtained from the screw simulator.