The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Dongyang Sun - One of the best experts on this subject based on the ideXlab platform.
-
High-shear rate rheometry of micro-nanofibrillated cellulose (CMF/CNF) suspensions using rotational rheometer
Cellulose, 2018Co-Authors: Saumil Sudhir Vadodaria, Amaka J. Onyianta, Dongyang SunAbstract:Suspensions of cellulose micro- and nanofibrils are widely used in coatings, fibre spinning, 3D printing and as rheology modifiers where they are frequently exposed to shear rates > 104 s−1, often within small confinements. High-shear rate rheological characterisation for these systems is therefore vital. Rheological data at high-shear rates are normally obtained using capillary and microfluidic Rheometers, which are found in relative scarcity within research facilities compared to rotational Rheometers. Also, secondary flows and wall depletion prevalent at such high-shear rates often go unnoticed or unquantified, rendering the measurement data unreliable. Reliable high shear rate rheometry using rotational Rheometers is therefore desirable. Suspension of TEMPO-oxidised CMF/CNF was tested for its high-shear rate rheological properties using parallel plate geometry at measurement gaps 150–40 µm and concentric cylinder at 1 mm gap. The errors from gap setting, radial dependence of shear stress and wall depletion were quantified and accounted for. Viscosity data from 0.1 to 30,000 s−1 shear rates was constructed using both geometries in agreement. Possibilities of secondary flows, radial migration of fluid and viscous heating were ruled out. Steady shear flow data of CMF/CNF suspension from 0.1 to 30,000 s−1 obtained using rotational rheometer
-
high shear rate rheometry of micro nanofibrillated cellulose cmf cnf suspensions using rotational rheometer
Cellulose, 2018Co-Authors: Saumil Sudhir Vadodaria, Amaka J. Onyianta, Dongyang SunAbstract:Suspensions of cellulose micro- and nanofibrils are widely used in coatings, fibre spinning, 3D printing and as rheology modifiers where they are frequently exposed to shear rates > 104 s−1, often within small confinements. High-shear rate rheological characterisation for these systems is therefore vital. Rheological data at high-shear rates are normally obtained using capillary and microfluidic Rheometers, which are found in relative scarcity within research facilities compared to rotational Rheometers. Also, secondary flows and wall depletion prevalent at such high-shear rates often go unnoticed or unquantified, rendering the measurement data unreliable. Reliable high shear rate rheometry using rotational Rheometers is therefore desirable. Suspension of TEMPO-oxidised CMF/CNF was tested for its high-shear rate rheological properties using parallel plate geometry at measurement gaps 150–40 µm and concentric cylinder at 1 mm gap. The errors from gap setting, radial dependence of shear stress and wall depletion were quantified and accounted for. Viscosity data from 0.1 to 30,000 s−1 shear rates was constructed using both geometries in agreement. Possibilities of secondary flows, radial migration of fluid and viscous heating were ruled out. Steady shear flow data of CMF/CNF suspension from 0.1 to 30,000 s−1 obtained using rotational rheometer
Luc Avérous - One of the best experts on this subject based on the ideXlab platform.
-
rheology to understand and optimize processibility structures and properties of starch polymeric materials
Progress in Polymer Science, 2012Co-Authors: Peter J. Halley, Luc AvérousAbstract:This paper reviews the state of the art in the field of the rheology of starch polymers, including specially designed rheometric techniques and complex rheology as influenced by different conditions. In terms of rheometric techniques, off-line extruder-type capillary/slit Rheometers are commonly used but subsequent changes during measurement often occur as starch structures are highly sensitive to thermomechanical treatment. An in-line rheometer set-up with a double-channel die incorporated to the processing extruder is a direct and effective method to minimize the processing history change at different testing shear rates. In addition, pre-shearing, multipass, and mixer-type Rheometers are also suitable for starch polymers. The rheological behavior of starch polymeric materials can be greatly impacted by their formulation (botanical source, plasticizer and additive type and content, and the structure related to blend or composite) and processing conditions (temperature, mechanical energy, etc.). Starch polymer melts exhibit shear-thinning and extension-thinning behaviors, and shows strong elastic properties. A wide range of rheological models, considering formulation and processing conditions, have been reviewed for different multiphase systems. The rheological behavior can also be related to the compatibility (blends, composites), expansion/foaming properties, film blowing properties, etc. The significance of processing rheology of starch polymers lies in characterizing the complex melting and flow behaviors, characterizing the viscoelastic properties, determining optimal processing method and conditions, and better controlling the quality of the final products.
-
Rheology to understand and optimize processibility, structures and properties of starch polymeric materials
Progress in Polymer Science (Oxford), 2012Co-Authors: Fengwei Xie, Peter J. Halley, Luc AvérousAbstract:This paper reviews the state of the art in the field of the rheology of starch polymers, including specially designed rheometric techniques and complex rheology as influenced by different conditions. In terms of rheometric techniques, off-line extruder-type capillary/slit Rheometers are commonly used but subsequent changes during measurement often occur as starch structures are highly sensitive to thermomechanical treatment. An in-line rheometer set-up with a double-channel die incorporated to the processing extruder is a direct and effective method to minimize the processing history change at different testing shear rates. In addition, pre-shearing, multipass, and mixer-type Rheometers are also suitable for starch polymers. The rheological behavior of starch polymeric materials can be greatly impacted by their formulation (botanical source, plasticizer and additive type and content, and the structure related to blend or composite) and processing conditions (temperature, mechanical energy, etc.). Starch polymer melts exhibit shear-thinning and extension-thinning behaviors, and shows strong elastic properties. A wide range of rheological models, considering formulation and processing conditions, have been reviewed for different multiphase systems. The rheological behavior can also be related to the compatibility (blends, composites), expansion/foaming properties, film blowing properties, etc. The significance of processing rheology of starch polymers lies in characterizing the complex melting and flow behaviors, characterizing the viscoelastic properties, determining optimal processing method and conditions, and better controlling the quality of the final products. © 2011 Elsevier Ltd.
Saumil Sudhir Vadodaria - One of the best experts on this subject based on the ideXlab platform.
-
High-shear rate rheometry of micro-nanofibrillated cellulose (CMF/CNF) suspensions using rotational rheometer
Cellulose, 2018Co-Authors: Saumil Sudhir Vadodaria, Amaka J. Onyianta, Dongyang SunAbstract:Suspensions of cellulose micro- and nanofibrils are widely used in coatings, fibre spinning, 3D printing and as rheology modifiers where they are frequently exposed to shear rates > 104 s−1, often within small confinements. High-shear rate rheological characterisation for these systems is therefore vital. Rheological data at high-shear rates are normally obtained using capillary and microfluidic Rheometers, which are found in relative scarcity within research facilities compared to rotational Rheometers. Also, secondary flows and wall depletion prevalent at such high-shear rates often go unnoticed or unquantified, rendering the measurement data unreliable. Reliable high shear rate rheometry using rotational Rheometers is therefore desirable. Suspension of TEMPO-oxidised CMF/CNF was tested for its high-shear rate rheological properties using parallel plate geometry at measurement gaps 150–40 µm and concentric cylinder at 1 mm gap. The errors from gap setting, radial dependence of shear stress and wall depletion were quantified and accounted for. Viscosity data from 0.1 to 30,000 s−1 shear rates was constructed using both geometries in agreement. Possibilities of secondary flows, radial migration of fluid and viscous heating were ruled out. Steady shear flow data of CMF/CNF suspension from 0.1 to 30,000 s−1 obtained using rotational rheometer
-
high shear rate rheometry of micro nanofibrillated cellulose cmf cnf suspensions using rotational rheometer
Cellulose, 2018Co-Authors: Saumil Sudhir Vadodaria, Amaka J. Onyianta, Dongyang SunAbstract:Suspensions of cellulose micro- and nanofibrils are widely used in coatings, fibre spinning, 3D printing and as rheology modifiers where they are frequently exposed to shear rates > 104 s−1, often within small confinements. High-shear rate rheological characterisation for these systems is therefore vital. Rheological data at high-shear rates are normally obtained using capillary and microfluidic Rheometers, which are found in relative scarcity within research facilities compared to rotational Rheometers. Also, secondary flows and wall depletion prevalent at such high-shear rates often go unnoticed or unquantified, rendering the measurement data unreliable. Reliable high shear rate rheometry using rotational Rheometers is therefore desirable. Suspension of TEMPO-oxidised CMF/CNF was tested for its high-shear rate rheological properties using parallel plate geometry at measurement gaps 150–40 µm and concentric cylinder at 1 mm gap. The errors from gap setting, radial dependence of shear stress and wall depletion were quantified and accounted for. Viscosity data from 0.1 to 30,000 s−1 shear rates was constructed using both geometries in agreement. Possibilities of secondary flows, radial migration of fluid and viscous heating were ruled out. Steady shear flow data of CMF/CNF suspension from 0.1 to 30,000 s−1 obtained using rotational rheometer
Amaka J. Onyianta - One of the best experts on this subject based on the ideXlab platform.
-
High-shear rate rheometry of micro-nanofibrillated cellulose (CMF/CNF) suspensions using rotational rheometer
Cellulose, 2018Co-Authors: Saumil Sudhir Vadodaria, Amaka J. Onyianta, Dongyang SunAbstract:Suspensions of cellulose micro- and nanofibrils are widely used in coatings, fibre spinning, 3D printing and as rheology modifiers where they are frequently exposed to shear rates > 104 s−1, often within small confinements. High-shear rate rheological characterisation for these systems is therefore vital. Rheological data at high-shear rates are normally obtained using capillary and microfluidic Rheometers, which are found in relative scarcity within research facilities compared to rotational Rheometers. Also, secondary flows and wall depletion prevalent at such high-shear rates often go unnoticed or unquantified, rendering the measurement data unreliable. Reliable high shear rate rheometry using rotational Rheometers is therefore desirable. Suspension of TEMPO-oxidised CMF/CNF was tested for its high-shear rate rheological properties using parallel plate geometry at measurement gaps 150–40 µm and concentric cylinder at 1 mm gap. The errors from gap setting, radial dependence of shear stress and wall depletion were quantified and accounted for. Viscosity data from 0.1 to 30,000 s−1 shear rates was constructed using both geometries in agreement. Possibilities of secondary flows, radial migration of fluid and viscous heating were ruled out. Steady shear flow data of CMF/CNF suspension from 0.1 to 30,000 s−1 obtained using rotational rheometer
-
high shear rate rheometry of micro nanofibrillated cellulose cmf cnf suspensions using rotational rheometer
Cellulose, 2018Co-Authors: Saumil Sudhir Vadodaria, Amaka J. Onyianta, Dongyang SunAbstract:Suspensions of cellulose micro- and nanofibrils are widely used in coatings, fibre spinning, 3D printing and as rheology modifiers where they are frequently exposed to shear rates > 104 s−1, often within small confinements. High-shear rate rheological characterisation for these systems is therefore vital. Rheological data at high-shear rates are normally obtained using capillary and microfluidic Rheometers, which are found in relative scarcity within research facilities compared to rotational Rheometers. Also, secondary flows and wall depletion prevalent at such high-shear rates often go unnoticed or unquantified, rendering the measurement data unreliable. Reliable high shear rate rheometry using rotational Rheometers is therefore desirable. Suspension of TEMPO-oxidised CMF/CNF was tested for its high-shear rate rheological properties using parallel plate geometry at measurement gaps 150–40 µm and concentric cylinder at 1 mm gap. The errors from gap setting, radial dependence of shear stress and wall depletion were quantified and accounted for. Viscosity data from 0.1 to 30,000 s−1 shear rates was constructed using both geometries in agreement. Possibilities of secondary flows, radial migration of fluid and viscous heating were ruled out. Steady shear flow data of CMF/CNF suspension from 0.1 to 30,000 s−1 obtained using rotational rheometer
John M. Dealy - One of the best experts on this subject based on the ideXlab platform.
-
a high pressure sliding plate rheometer for polymer melts
Journal of Rheology, 1999Co-Authors: Francois Koran, John M. DealyAbstract:A high-pressure sliding plate rheometer has been developed to investigate the effect of pressure on the rheological behavior of molten polymers and elastomers. The new rheometer operates at pressures up to 70 MPa and temperatures up to 225 °C. The sample is subjected to simple shear, and the resulting shear stress is measured locally using a shear stress transducer. This design eliminates the inhomogeneities in pressure and shear rate that occur in high pressure capillary and slit Rheometers. Preliminary evaluation of the new instrument was carried out using a linear low density polyethylene. Viscosity curves were generated at pressures ranging from atmospheric pressure to 70 MPa, and the pressure coefficient of viscosity was determined. Experiments were also carried out in step strain and large amplitude oscillatory shear, demonstrating the new rheometer’s use to study the nonlinear viscoelastic behavior of molten polymers. Finally, this instrument was used to study strain-induced crystallization.
-
frequency response of a shear stress transducer installed in a sliding plate rheometer
Journal of Rheology, 1998Co-Authors: John M. Dealy, Ranjit S JeyaseelanAbstract:A number of laboratories are currently using sliding plate Rheometers equipped with shear stress transducers to study the nonlinear viscoelasticity and slip of molten polymers. In making such measurements, it is sometimes essential to know to what degree the dynamic response of the shear stress transducer itself is influencing the output signal. Experiments should be designed to minimize this effect, but some attenuation and phase shift is inevitable because of the presence of polymer inside the transducer. We have measured the dynamic response of a shear stress transducer in situ in a sliding plate rheometer for two molten polyethylenes. We have also developed a model for the transducer response. In oscillatory shear experiments above a frequency of 1 Hz, the amplitude ratio and phase lead are significant for both materials studied.