* The abstracts are available for each conference contribution when you click on the corresponding title.
July 26, 2023
8:00 – 8:50
Registration
8:50 – 9:00
Welcome
EXTENSIONAL RHEOMETRY
(Chairman: Helmut Münstedt)
9:00 – 9:30
Extensional Rheometry via Flow through an Abrupt Contraction: a Short Review
Autor:
Christopher W. Macosko
Affiliation:
Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. Minneapolis, MN 55455 USA.
Contact
Corresponding author:
Abstract:
This review assesses the advantages and limitations of extensional rheometry using flow through an abrupt contraction. Analyses used to estimate extensional viscosity from entrance pressure drop and flow rate measurements are reviewed. These are compared with each other and to results from other extensional rheometers. A great advantage of entrance flow extensional rheometry is that it is perhaps the easiest method to obtain extensional data, especially with complex and industrial fluids such as hot melt adhesives, dough, emulsions and polymer melts, since it is readily adapted to standard capillary rheometers. Disadvantages are that the flow is not homogeneous and shear is always present. Nonetheless, pressure drop through an abrupt contraction can be especially useful in quickly ranking extensional effects between different material formulations.
Christopher W. Macosko | University of Minnesota | Minneapolis, USA
9:30 – 10:00
Advances in Determination of Extensional Viscosities for Polymer Melts from Entrance Pressure Drop Measurements
Autors:
Martin Zatloukal a), Jiří Drábek b), Jan Musil c), Jiří Juračka d) and Jiří Šidla e)
Affiliation:
Department of Polymer Engineering, Faculty of Technology, Tomas Bata University in Zlín, Vavreckova 5669, 760 01 Zlin, Czech Republic.
Contacts:
a) Corresponding author:
b)
c)
d)
e)
Abstract:
New circular and rectangular multi-piece orifice dies were used to determine uniaxial and planar extensional viscosities of linear and branched polyolefin melts from entrance pressure drop measurements using a high-pressure capillary rheometer. The new orifice die design suppresses sticking of the material at the die exit, which enables accurate measurement of the entrance pressure drop and precise evaluation of the extrudate swell. The multi-piece nature of the orifice dies makes it possible to reduce the dimensions of the flow channel significantly, which enables measurements of shear and extensional viscosities at extremely high strain rates. The new concept also allows the maximum achievable Hencky strain to be set at a constant extensional strain rate. The ability of different constitutive equations to describe the measured data was tested. The obtained results are considered valuable with respect to the optimization of the film casting process for the production of polymeric energy storage membranes. The authors wish to acknowledge the Grant Agency of the Czech Republic (Grant No. 21–09174S) for the financial support and NETZSCH Gerätebau GmbH for providing the Rosand RH10-2 capillary rheometer.
Martin Zatloukal | Tomas Bata University in Zlin | Zlín, Czech Republic
10:00 – 10:30
Cofee break & Exhibition
INTRODUCTION OF NOVEL RHEOLOGICAL TOOLS
(Chairman: Manfred Wilhelm)
10:30 – 11:00
Polymer Rheology: from Material Characterization to Process Simulation with NETZSCH Rheometers
Autors:
Onur Özgul a) and Senol Gezgin b)
Affiliation:
NETZSCH-Gerätebau GmbH, Wittelsbacherstrasse 42, 95100 Selb, Germany.
Contacts:
a) Corresponding author:
b)
Abstract:
NETZSCH Analyzing & Testing, Germany, provides beside thermoanalytical instruments the complete rheometer series for the widest range of shear rate tailored to various applications.
The combination of rotational and capillary rheometry opens up a wide range of characterization possibilities specifically for polymer melts. Furthermore, the rheological behavior of the material to be processed influences the entire process from the material design to the optimization of the processing machines. This challenge can be overcome by deep insight into the rheological behavior of the polymer. This includes having a closer at the full sample including the loading to unloading process.
With the rotational rheometer of the Kinexus Prime+-series and its user friendly interchangeable temperature cartridges, various quick-connect geometries, and diverse accessories, high shear rates can be achieved depending on the viscosity of the sample. A variety of Kinexus models (e.g., Ultra+, Pro+ and Lab+) differ among other things in their torque range and resolution for both viscosimetry and oscillation offering a fitting solution for laboratory and processing demands. The versatile and intuitive rSpace software offers very flexible SOP type sequences. With complete access to raw data from loading to measurement to unloading a data acquisition rate of 5kHz, the entire sample history can be recorded.The Rosand capillary rheometer series with different force ranges covers the highest shear rate ranges up to approximately 108 s-1. The RH7 and RH10 models are floor-standing instruments for measurements with forces up to 100kN, allow the real extrusion and injection molding parameters. The flexible table top instrument RH2000 reaches forces up to 20 kN, ideal for laboratory routine tests. Thanks to the various capillary die geometries, lower shear rates are achievable as well and offer the possibility to reach the overlapping region of capillary and rotational data. In addition to the constant shear test, measurements of extensional viscosity and melt strength (the so-called haul-off test), die swelling and of pVT become possible. The Flowmaster software provides beside data analysis the possibility to mimic processes like injection moulding or extrusion processes.
Onur Özgul | NETZSCH-Gerätebau GmbH | Selb, Germany
11:00 – 11:30
Continuous Twin-screw Extrusion and Rheological Analysis of Electrode Slurries for Lithium-ion Battery Manufacturing
Autor:
O. Ansgar Frendel
Affiliation:
Thermo Fisher Scientific, Germany.
Contact:
Corresponding author:
Abstract:
Lithium-ion batteries (LIBs) are widely used in portable electronics, electric vehicles, and grid storage, due to their high energy density and long cycle life. LIBs consist of a graphite-coated copper foil, which acts as the anode, an aluminum foil coated with active materials as cathode, and a polymer separator film that separates both electrodes and only allows lithium ions to pass. A liquid electrolyte in which lithium salt is dissolved completes the setup.
The lithium-ion battery manufacturing process involves many steps and includes the preparation and coating of anode and cathode slurries. Proper mixing and homogenous coating processes are essential for achieving batteries with a high capacity and high number of charging cycles. During the manufacturing and coating steps, battery slurries are exposed to a wide range of shear conditions. Rotational and oscillatory rheometry enables the quantification of the viscoelastic properties, that are needed to verify the proper mixing and homogeneous distribution of active components, to predict storage behavior and stability of the electrode slurries, and to understand behavior during the coating process.
In this contribution we will introduce continuous twin-screw compounding for the manufacturing of electrode slurries, along with the advantages of a complete rheological investigation using a rotational rheometer over single-point measurements with traditional spindle viscometers.
Ansgar Frendel | Thermo Fisher Scientific | Dreieich, Germany
11:30 – 12:00
Combined Rheology and Spectroscopy Methods to Characterize the Cure Behavior of Epoxy Resins
Autors:
Loredana Völker-Pop a), José Alberto Rodríguez Agudo b) and Christopher Giehl c)
Affiliation:
Anton Paar Germany GmbH, Ostfildern, Germany.
Contacts:
a) Corresponding author:
b)
c)
Abstract:
High performance epoxy resins, pure or in combination with other materials like carbon fiber or fiberglass, are important materials for a wide range of applications and especially for automotive and aerospace industries. To ensure advanced materials with exceptional strength, durability and versatility for a wide range of applications, formulation knowledge and control over curing time and temperature are essential. To characterize the behavior of epoxy resins before, during and after curing, a rheometer has been used. The curing involves a gradual change in the rheological properties (macro-properties) of the sample as a direct consequence of the chemical reaction in which the epoxy and hardener are converted into a three-dimensional network. The Winter-Chambon criterion, based on a dynamic multiwave test, was used to determine the sol/gel transient point, also called gel point. The transition from liquid-like to solid-like behavior can be additionally monitored by dielectric spectroscopy, were the changes of the dipole’s mobility reflect the progress of the curing reaction. Additional information is gained by Raman spectroscopy, providing a unique fingerprint of functional groups and the chemical backbone structure of the material. Besides, Raman spectroscopy give further information about chemical reaction rate, pot life and curing times, or the presence of intermediate or by-product species.
Loredana Völker-Pop | Anton Paar Germany GmbH | Ostfildern, Germany
12:00 – 13:30
Lunch & Exhibition
RHEOLOGY OF POLYMERIC MATERIALS I
(Chairman: Savvas George Hatzikiriakos)
13:30 – 14:00
Strain Hardening of Various Polymer Melts
Autor:
Helmut Münstedt
Affiliation:
Institute of Polymer Materials, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstr. 7 D-91058 Erlangen, Germany.
Contact:
Corresponding author:
Abstract:
Various strain-hardening features of polymer melts in uniaxial extension are described. Of special interest is the dependence of strain hardening on elongational rate. Long-chain branched polyethylene, commercial polystyrenes and their blends with high molar mass components exhibit strain hardening becoming more pronounced with increasing strain rate. For linear polypropylenes, strain hardening is not found within the experimental window. Adding a small amount of a linear polyethylene with ultrahigh molar mass (UHMWPE) results in strain hardening increasing with decreasing rate. Rouse times are used to qualitatively interpret the experimental results on polystyrene. The non strain hardening behavior of linear PP and HDPE can be made plausible by the Rouse model. But for a qualitative understanding of the rate dependence of strain hardening of the PP/UHMWPE blend, the existence of a separate phase of the minor component and special deformation processes at the interface with the matrix have to be postulated.
Helmut Münstedt | Friedrich-Alexander University Erlangen-Nürnberg | Erlangen, Germany
14:00 – 14:30
Shear Flow of Bimodal Polyethylene: Slip and Surface Fractionation
Autors:
M. Sattari 1), S. Kwakye-Nimo 1), Y. W. Inn 2) and P. M. Wood-Adams 3, a)
Affiliations:
1) Department of Mechanical, Industrial and Aerospace Engineering, Concordia University, Montreal, Quebec, Canada H3G 1M8.
2) Chevron Phillips Chemical, Bartlesville, OK 74004, USA.
3) Department of Chemical and Materials Engineering, Concordia University, Montreal, Quebec, Canada H3G 1M8.
Contact:
a) Corresponding author:
Abstract:
The slip behavior and surface fractionation of bimodal molecular weight distribution polyethylenes are studied under simple shear. The slip velocity was found to depend strongly on short-chain content. Surface fractionation was also shown to occur in simple shear flow in the presence of slip resulting in a debris layer left behind on the surface that is enriched in short and moderate length chains.
Paula Marie Wood-Adams | Concordia University | Montreal, Canada
14:30 – 15:00
Cofee break & Exhibition
RHEOLOGY OF POLYMERIC MATERIALS II
(Chairman: Roland Kádár)
15:00 – 15:30
Self-healing Behavior of Aminated Polyolefins with Dynamic Associations
Autors:
B. M. Yavitt 1, 2), T. Tomkovic 1), D. J. Gilmour 2), Z. Zhang 1), N. Kuanr 2), E. van Ruymbeke 3), L. L. Schafer 2, a) and S. G. Hatzikiriakos 1, b)
Affiliations:
1) Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, B.C, Canada, V6T 1Z3.
2) Department of Chemistry, University of British Columbia, Vancouver, B.C, Canada, V6T 1Z4.
3) Bio-and Soft Matter, Institute of Condensed Matter and Nanosciences, Universite Catholique de Louvain, Croix du Sud 1, B-1348 Louvain-la-Neuve, Belgium.
Contacts:
a)
b) Corresponding author:
Abstract:
The rheological and self-healing behavior of a class of catalytically synthesized amine functionalized polyolefins is investigated. These materials possess tunable rheological properties and display autonomous self-healing. The linear viscoelastic properties are modelled using a tube based Time Marching Algorithm to calculate several model parameters that describe the individual chain dynamics. The self-healing response is described by findings from the reptation model as well as recent theory on associating polymer networks with reversible bonds.
Savvas George Hatzikiriakos | University of British Columbia | Vancouver, Canada
15:30 – 16:00
Recent Advances in Polymer Viscoelasticity from General Rigid Bead-rod Theory
Autors:
M. A. Kanso 1, a) and A. J. Giacomin 1, 2, 3, 4, b)
Affiliations:
1) Chemical Engineering Department, Polymers Research Group, Queen’s University, Kingston, Ontario, CANADA K7L 3N6.
2) Mechanical and Materials Engineering Department, Queen’s University, Kingston, Ontario, CANADA K7L 3N6.
3) Physics, Engineering Physics and Astronomy Department, Queen’s University, Kingston, Ontario, CANADA K7L 3N6.
4) Mechanical Engineering Department, University of Nevada, Reno, Nevada 89557-0312, USA.
Contacts:
a)
b)
Abstract:
One good way to explain the elasticity of a polymeric liquid, is to just consider the orientation distribution of the macromolecules. When exploring how macromolecular architecture affects the elasticity of a polymeric liquid, we find general rigid bead-rod theory to be both versatile and accurate. This theory sculpts macromolecules using beads and rods. Whereas beads represent points of Stokes flow resistances, the rods represent rigid separations. In this way, how the shape of the macromolecule affects its rheological behavior in suspension is determined. Our work shows the recent advances in polymer viscoelasticity using general rigid bead-rod theory, including advances applied on the coronavirus. The coronavirus is always idealized as a spherical capsid with radially protruding spikes. However, histologically, in the tissues of infected patients, capsids in cross section are elliptical, and only sometimes spherical. This capsid ellipticity implies that coronaviruses are oblate or prolate or both. We call this diversity of shapes, pleomorphism. Recently, the rotational diffusivity of the spherical coronavirus in suspension was calculated, from first principles, using general rigid bead-rod theory. We did so by beading the spherical capsid, and then also by replacing each of its bulbous spikes with a single bead. In this paper, we use energy minimization for the spreading of the spikes, charged identically, over the oblate or prolate capsids. We use general rigid bead-rod theory to explore the role of such coronavirus cross-sectional ellipticity on its rotational diffusivity, the transport property around which its cell attachment revolves. We learn that coronavirus ellipticity drastically decreases its rotational diffusivity, be it oblate or prolate.
Alan Jeffrey Giacomin | University of Nevada | Reno, USA
18:30
Conference dinner
July 27, 2023
0:00 – 0:00
EVENT
RHEOLOGY OF POLYMERIC MATERIALS III
(Chairman: Alan Jeffrey Giacomin)
8:30 – 9:00
Shear and Elongational Rheology of Model Polystyrene Pom-Poms
Autors:
Valerian Hirschberg a), Max G. Schußmann b) and Marie-Christin Röpert c)
Affiliation:
Institute of Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Engesserstraße 18, 76131 Karlsruhe, Germany.
Contacts:
a) Corresponding author:
b)
c)
Abstract:
Understanding the effect of branching on the melt rheological properties in shear and elongational flow is of fundamental interest to polymer science. Besides the number and the molecular weight of the arms as well as of the backbone, the exact location of the branching points, thus the exact topology is key to control shear and extensional rheological properties. Fourteen low-disperse, polystyrene pom-pom samples were synthesized with two optimized synthetic routes via a combination of anionic polymerization and grafting onto, in a scale of up to 300 g per model system. The molecular parameters of the pom-poms such as molecular weight of the backbone (MW,b = 100 – 400 kg.mol-1), of the arms (MW,a = 7 – 300 kg.mol-1) and the arm number at each end (q = 5 – 30) are systematically varied. The shear and elongational behavior are investigated experimentally and analyzed within the framework of the pom-pom model. High shear thinning is found in small amplitude oscillatory shear (SAOS) measurements. The results in shear revealed up to five times lower zero-shear viscosities for pom-poms compared to combs with similar MW,b, MW,a and total arm number. For the pom-poms, maximum strain hardening factors beyond 100 are found in elongation, depending for the pom-poms exclusively on the total arm number, as the elongational viscosity is by a factor of [q2/ln(√3×q)] above the linear-viscoelastic envelope (LVE) in the backbone rubber plateau, as predicted by the pom-pom model and the Considère criterion.
Valerian Hirschberg | Karlsruhe Institute of Technology (KIT) | Karlsruhe, Germany
9:00 – 9:30
Modeling Elongational Flow and Fracture of Long-chain Branched Polymer Melts
Autors:
Manfred H. Wagner 1, a) and Valerian Hirschberg 2, b)
Affiliations:
1) Polymer Engineering and Physics, Berlin Institute of Technology (TU Berlin), Ernst-ReuterPlatz 1, D-10857 Berlin, Germany.
2) Institute of Chemical Technology and Polymer Chemistry (ITCP), Karlsruhe Institute of Technology (KIT), Engesserstraße 18, 76131 Karlsruhe, Germany.
Contacts:
a) Corresponding author:
b)
Abstract:
Based exclusively on the linear-viscoelastic characterization and a single nonlinear material parameter, the dilution modulus GD, the Hierarchical Multi-mode Molecular Stress Function (HMMSF) model predicts the elongational start-up viscosity of long-chain branched (LCB) polymer melts quantitatively up to the point of fracture or up to the maximum of the elongational stress growth coefficient. In addition to the concepts of hierarchical relaxation and dynamic dilution, the HMMSF model was so far based on the concept of interchain tube pressure limiting chain stretch. Here, we replace the tube pressure idea by the Enhanced Relaxation of Stretch (ERS) model, which assumes that a decreasing tube diameter with increasing deformation leads to faster Rouse relaxation at smaller length scales. We also take the entropic fracture criterion into account. The modified HMMSF model is validated by comparison with elongational viscosity data of well-defined low-dispersive polystyrene Pom-Pom model systems, for which the dilution modulus GD is equal to the plateau modulus. If not preceded by fracture, branch point withdrawal will occur in LCB melts at higher Hencky strains and strain rates. This can be modeled by a stretch parameter, which quantifies the characteristic stretch when branch points and side arms are withdrawn into the backbone tube. We show that the predictions of this Extended Hierarchical Multi-mode Molecular Stress Function (EHMMSF) model are in excellent agreement with experimental elongational data of three commercial low-density polyethylene melts.
Manfred Hermann Wagner | Berlin Institute of Technology (TU Berlin) | Berlin, Germany
9:30 – 11:00
Cofee break & Poster section & Exhibition
Role of Nucleating Agent on Molecular Orientation of Polypropylene Crystallized under Flow Field
Autors:
Khunanya Janchai 1, a), Takumitsu Kida 1, b), Takahiro Inoue 2, c), Shohei Iwasaki 1, 2, d) and Masayuki Yamaguchi 1, e)
Affiliations:
1) Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
2) New Japan Chemical Co., Ltd., 1-5-4 Hikaridai, Seika-cho, Soraku-gun, Kyoto 612-0237, Japan.
Contacts:
a) Corresponding author:
b)
c)
d)
e)
Abstract:
Crystallization behavior after shear was studied using isotactic polypropylene containing a fibrous nucleating agent using a polarized optical microscope attached with a parallel-plate shear device. The addition of a fibrous nucleating agent greatly enhanced the crystallization after applying shear flow even at a low shear rate. As a result, a high level of molecular orientation to the flow direction was attained, which must be responsible for high modulus. This was attributed to the formation of a pseudo shish-kebab structure, in which the nucleating agent acted as shish.
Khunanya Janchai | Japan Advanced Institute of Science and Technology | Nomi, Japan
Effect of Pre-Shear on Flow-Induced Crystallization of Branched Polypropylene
Autors:
Jiri Drabek 1, a), Khunanya Janchai 2, b), Takumitsu Kida 2, c), Masayuki Yamaguchi 2, d) and Martin Zatloukal 1, e)
Affiliations:
1) Department of Polymer Engineering, Faculty of Technology, Tomas Bata University in Zlín, Vavrečkova 5669, 760 01 Zlín, Czech Republic.
2) Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.
Contacts:
a) Corresponding author:
b)
c)
d)
e)
Abstract:
In this work, the effect of pre-shearing time on the crystallization of long-chain branched polypropylene(LCB-PP) subjected to simultaneous cooling and shearing was investigated using a polarized optical microscope equipped with a parallel-plate shear device and a photodetector. Crystallinity and orientation were evaluated using small-angleX-ray scattering, wide-angle X-ray diffraction and Fourier-transform IR instrument. Increasing the pre-shear time was found to decrease crystallization temperature, crystallinity and orientation (reaching practically constant values at long pre-shear times), suggesting that increasing the pre-shear time causes the chain branches to be more aligned along the backbone, reducing their efficiency, the LCB-PP melt becomes less elastic and the flow-induced crystallization is minimized. This effect is significant because the crystallization temperature has decreased from 137.0°C to 122.8°C due to pre-shear with followed mixed shear and temperature induced crystallization compared to the crystallization temperature of 118.5°C achieved at purely thermally induced crystallization conditions.
Jiri Drabek | Tomas Bata University in Zlín | Zlín, Czech Republic
Surface Instability Detection in Highly-Filled Biocomposites from Inline Imaging during Extrusion
Autors:
Sajjad Pashazadeh 1, a), Tobias Moberg 2, b), Anders Brolin 3, c) and Roland Kádár 1, 4, 5, d)
Affiliations:
1) Chalmers University of Technology, Department of Industrial and Materials Science, Gothenburg, SE 412 96, Sweden.
2) Stora Enso AB, Circular Solutions, Packaging Solutions, Hylte Mill, SE 314 81, Hyltebruk, Sweden.
3) Stora Enso AB, Group Innovation and R&D, Karlstad Research Center, SE 650 09, Karlstad, Sweden.
4) FibRe-Centre for Lignocellulose-based Thermoplastics, Department of Chemistry and Chemical Engineering, Chalmers University of Technology, Gothenburg, SE 412 96, Sweden.
5) Wallenberg Wood Science Centre, Chalmers University of Technology, Gothenburg, SE 412 96, Sweden.
Contacts:
a) Corresponding author:
b)
c)
d)
Abstract:
The processing of wood fiber biocomposites, and in particular, the extrusion, is accompanied by multiple challenges, among which agglomeration, entanglement, slip, or surface instabilities being the most common ones. In the current work, we focus on the dynamics of surface instabilities during the single screw extrusion of highly filled wood fiber biocomposites. The biocomposites are polypropylene based with up to 40 wt% wood fiber content of custom compositions based on the commercial-grade by Stora Enso. To detect and quantify the dynamics of surface instabilities, inline image analysis was applied using an optical visualization system positioned at the die exit. Therefrom, space-time diagrams were constructed, and after that, via 2D-Fourier transform analysis, the spatio-tempoal spectral dynamics of the surface instabilities were determined as a function of the die (apparent) shear rate. The spectral dynamics show that melt instabilities of 40 wt% for example, detected via their characteristic (temporal) frequency and (spatial) wavenumber, dissipate with increasing the shear rate, such that at shear rates above ca. 90 1/s, no characteristic frequency and wavenumber can be distinguished i.e. instabilities can no longer be observed on the surface of the extrudates.
Sajjad Pashazadeh | Chalmers University of Technology | Göteborg, Sweden
Modeling of Extrusion Film Casting Process for Battery Separator Membranes Production using Variable Heat Transfer Coefficient
Autors:
Tomas Barborik a) and Martin Zatloukal b)
Affiliation:
Department of Polymer Engineering, Faculty of Technology, Tomas Bata University in Zlín, Vavreckova 5669, 760 01 Zlin, Czech Republic.
Contacts:
a) Corresponding author:
b)
Abstract:
The main objective of this work is to investigate the advantages of using a variable versus constant heat transfer coefficient and its effects on the development of the temperature and crystallinity during the extrusion film casting operation under fast cooling conditions suitable for the production of advanced battery separators. For this purpose, a viscoelastic extrusion film casting model accounting for thermal effects, with newly adopted generalized heat transfer coefficient approach accounting for convection and radiation, including temperature and flow-induced crystallization was used, and the model predictions were compared with relevant experimental data. The results obtained indicate that the use of a variable HTC approach combined with flow-induced crystallization should be preferred, otherwise the model predictions do not capture the experimental data for film temperature and crystallinity. It is believed that the proposed model can bring a more detailed insight into the optimization of such manufacturing applications.
Tomas Barborik | Tomas Bata University in Zlín | Zlín, Czech Republic
Gibbs Free Energy Based Constitutive Relations for Elastic Solids and their Use in Mathematical Modelling of Viscoelastic Fluids
Autor:
Vít Průša
Affiliation:
Faculty of Mathematics and Physics, Charles University, Sokolovská 83, Praha 8 – Karlín, CZ 186 75, Czech Republic.
Contact:
Corresponding author:
Abstract:
Viscoelastic fluids are non-Newtonian fluids that exhibit both “viscous” and “elastic” characteristics in virtue of the mechanisms used to store energy and produce entropy. Usually, the energy storage properties of such fluids are modeled using the same concepts as in the classical theory of nonlinear solids. Recently, new models for elastic solids have been successfully developed by appealing to implicit constitutive relations, and these new models offer a different perspective to the old topic of the elastic response of materials. In particular, a sub-class of implicit constitutive relations, namely relations wherein the left Cauchy–Green tensor is expressed as a function of stress, is of interest. We show how to use this new perspective in the development of mathematical models for viscoelastic fluids, and we provide a discussion of the thermodynamic underpinnings of such models. We focus on the use of Gibbs free energy instead of Helmholtz free energy, and using the standard Giesekus/Oldroyd-B models, we show how the alternative approach works in the case of well-known models. The proposed approach is straightforward to generalize to more complex settings wherein the classical approach might be impractical or even inapplicable.
Vít Průša | Brno University of Technology | Brno, Czech Republic
Gustav Jaumann and History of (Not Only) Rheology
Autor:
Miloslav Pekař
Affiliation:
Brno University of Technology, Faculty of Chemistry, Purkyňova 118, 612 00 Brno, Czech Republic.
Contact:
Corresponding author:
Abstract:
Gustav Jaumann was a German (Austrian) physicist who spent his professional career at universities in Bohemia and Moravia (first, Austrian-Hungarian monarchy, then Czechoslovakia). In rheology, he remains known for co-rotational derivative, usually bearing his name. He was born in 1863 in Karánsebes (today Romania), studied at technical universities in Prague and Vienna and at Charles University in Prague where he started in 1885 as an assistant to Ernst Mach and worked mainly in experimental physics. In 1893 he was appointed extraordinary professor of experimental physics and physical chemistry there. In 1901 he moved to Brno as a regular professor of physics at the German Technical University. In Brno he worked in theoretical physics, foundations of kinematics and mechanics and published his most important works in this area. He was influenced by ideas of J.W.Gibbs and introduced vector analysis in physics. However, his scope of scientific activity was broader, included also general principles of chemistry, entropy considerations and can be seen as a – rather forgotten – pioneer of non-equilibrium thermodynamics (of continua). His views and achievements can be found primarily in his two principal works: G. Jaumann, Die Grundlagen der Bewegungslehre. Barth Verlag, Leipzig, 1905. G. Jaumann, Geschlossenes System physikalischer und chemischer Diffrerentialgesetze. K. k. Hof- und Staatsdruckerei, Wien, 1911. Gustav Jaumann died in 1924 during trekking in the Austrian Alps. Manuscript of his last, summarizing work, numbering about two thousand pages, remained unpublished and is probably lost. Poster will present copies-examples of his published work and from his activity at university in Brno.
Miloslav Pekař | Brno University of Technology | Brno, Czech Republic
Food Packaging – from Multimaterials to Monomaterial
Autors:
Carolina Barros 3), Sónia Miranda 1), Olga Castro 2), O. S. Carneiro 3) and A. V. Machado 3)
Affiliations:
1) Innovation in Polymer Engineering (PIEP), University of Minho.
2) Vizelpas, Rua Da Fundição, 8, Vilarinho, Porto.
3) Institute for Polymers and Composites (IPC), Department of Polymer Engineering (DEP), University of Minho.
Abstract:
Nanocomposites, with well-dispersed particles, exhibit better performance when compared to micro-composites and the neat polymer. However, it is quite difficult to obtain nanocomposites with a good nanoclay (NC) dispersion in non-polar polymers . This study focuses on the development of LDPE films for food packaging industry and aims at improving LDPE oxygen barrier properties while maintaining other relevant characteristics, such as processability, easy post-processing, optical and mechanical properties. LDPE nanocomposites, with 1 and 2.5 wt.% NC and also compatibilized with 5 wt.% polyethylene grafted with maleic anhydride (PE-g-MA), were prepared to produce film samples by blown extrusion. The nanocomposites were characterized in terms of their morphology, thermal, rheological, mechanical, barrier and optical properties, through scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), rheological measurements, tensile tests, water vapor transmission, oxygen permeability tests and spectrophotometry. The results demonstrated good NC dispersion in the polymer matrix and decreased oxygen permeability in the compatibilized nanocomposite films. Overall, LDPE film properties were improved with NC added and have potential for food packaging as monomaterial.Nanocomposites, with well-dispersed particles, exhibit better performance when compared to micro-composites and the neat polymer. However, it is quite difficult to obtain nanocomposites with a good nanoclay (NC) dispersion in non-polar polymers . This study focuses on the development of LDPE films for food packaging industry and aims at improving LDPE oxygen barrier properties while maintaining other relevant characteristics, such as processability, easy post-processing, optical and mechanical properties. LDPE nanocomposites, with 1 and 2.5 wt.% NC and also compatibilized with 5 wt.% polyethylene grafted with maleic anhydride (PE-g-MA), were prepared to produce film samples by blown extrusion. The nanocomposites were characterized in terms of their morphology, thermal, rheological, mechanical, barrier and optical properties, through scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC), rheological measurements, tensile tests, water vapor transmission, oxygen permeability tests and spectrophotometry. The results demonstrated good NC dispersion in the polymer matrix and decreased oxygen permeability in the compatibilized nanocomposite films. Overall, LDPE film properties were improved with NC added and have potential for food packaging as monomaterial.
Ana Vera Machado | University of Minho | Guimarães, Portugal
Determination of Viscoelastic Properties of Collagen Matter Using Various Methods within Extrusion Rheometry
Autors:
Jan Štípek a), Jan Skočilas b), Rudolf Žitný c) and Jaromír Štancl d)
Affiliation:
Department of Process Engineering, Faculty of Mechanical Engineering, Czech Technical University in Prague, Technická 4, 166 09 Prague 6, Czech Republic.
Contacts:
a) Corresponding author:
b)
c)
d)
Abstract:
This contribution deals with the investigation of viscoelastic properties of the collagen matter using the extrusion rheometry. The bovine collagen matter with a high mass fraction of the collagen (8 %) is extracted from the calf skin and is used in the food industry as an edible sausage casing. Experiments were performed using the extrusion rheometer. Samples are pushed through the modified rectangular capillary (called the hole-pressure capillary) by the hydraulically driven piston. Bottom part of the capillary head is equipped with five pressure transducers monitoring pressures along the capillary. Upper capillary head is equipped with one pressure transducer mounted in the groove. The so-called hole pressure value can be measured by these experiments. The hole pressure is then used to evaluate the viscoelastic parameter: first normal stress difference N1. Other possible ways to determine the viscoelasticity of the collagen by extrusion are used in this contribution as well. The exit pressure method uses the pressure value in the position of capillary end. The value is reached by the extrapolation of pressure values from five pressure transducers. The jet swell evaluation method uses the image (photography) of the extruded sample and evaluates the expansion of material when it leaves the capillary. All methods were used to quantify the viscoelastic effect. Methods are compared with each other and their suitability to the collagen matter is discussed. The hole pressure method was found to have a solid data overlap with the exit pressure method (N1 ≈ 180 000 Pa) at high shear rates (γ̇ = 3500 s-1). The hole pressure ratio pHole/p2 was found to be between 13 and 19 % during experiments. The N1 values are compared with similar experiments in the literature with some positive similarities. All this despite the fact, that collagen data in this study are evaluated under much bigger shear rates.
Jan Štípek | Czech Technical University in Prague | Prague, Czech Republic
Dynamic Mechanical Analysis of Agarose Hydrogels and Its Relationship to Shear Oscillation
Autors:
Martin Kadlec a), Jiří Smilek b) and Miloslav Pekař c)
Affiliation:
Brno University of Technology, Faculty of Chemistry, Institute of physical and applied chemistry, Purkyňova 464/118, CZ-612 00 Brno, Czech Republic.
Contacts:
a) Corresponding author:
b)
c)
Abstract:
Hydrogels are materials, which offers a number of usage due to its unique properties such a biocompatibility or high water content. They might be utilized in wound dressing, tissue engineering or extracellular matrix modelling. For each application, materials with different characteristics are desired. Therefore, rheology characterization is essential in case of hydrogel studies. Besides more common shear rheology, dynamic mechanical analysis can provide a useful information about the material viscoelastic behaviour. In this case, an ability to resist to deformation is in form of tension/compression contrary to shear deformation in shear rheology. In this study, strain sweep testing both in shear as well as in DMA mode is studied on the agarose hydrogel. Besides comparison between these two approaches including Poisson’s ratio, some other variables, which can influence results, are discussed. Particularly, axial force during measurement and/or different measuring geometries were studied. Regarding to results, even small changes in axial force can have a significant impact on the viscoelastic modulus values. Therefore, control axial force measurement are preferred over the gap control measurement. Moreover, using the same geometry systems during measurement is essential in order to obtain valid and comparable results.
Martin Kadlec | Brno University of Technology | Brno, Czech Republic
Rheology of Polysaccharide based Self-Cross-Linked Injectable Hydrogel
Autors:
Nabanita Saha 1, 2, a), Fahanwi A Ngwabebhoh 1, b), Mainak Chaudhuri 1, c) and Petr Saha 1, d)
Affiliations:
1) Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Tr. T. Bati 5678, 76001 Zlin, Czech Republic.
2) Department of Polymer Engineering, Faculty of Technology, Tomas Bata University in Zlin, Vavrečkova 275, 76001 Zlin, Czech Republic.
Contacts:
a) Corresponding author:
b)
c)
d)
Abstract:
Injectable hydrogel systems are the current interest in health care or medical field for therapeutic agent delivery, disease/cancer therapy, and tissue engineering. On the other hand, polysaccharide-based hydrogels are appealing materials for biomedical applications due to their polyfunctionality, biodegradability as well as originality (origin from nature). Hence, attention has been given in preparation of polysaccharide based injectable hydrogel. But the stability, usability, and application of injectable hydrogel in the biomedical field is determined by rheological properties, which is the most significant features of injectable hydrogels. This article reports about rheological behaviors such as storage (G’) and loss modulus (G”), complex viscosity, shear stress and gel point of polysaccharide based injectable hydrogels prepared with oxidized bacterial cellulose, pectin, and chitosan, designated as S-0.5, S-0.75, S-1.0 and S-1.5. They appeared as transparent white, self-crosslinked, and soft polymeric gel with gel formation within less than 30 second possessing depicting viscoelastic properties under oscillatory shear deformation.
Nabanita Saha | Tomas Bata University in Zlín | Zlín, Czech Republic
Magneto-Active Ferrite-Based Paint Pigments
Autors:
Lenka Munteanu 1, a), Milan Masař 1, b), Michal Sedlačík 1, c), Miroslav Kohl 2, d) and Andrea Kalendová 2, e)
Affiliations:
1) Centre of Polymer Systems, University Institute, Tomas Bata University in Zlín, Třída T. Bati 5678, 760 01 Zlín, Czech Republic.
2) Faculty of Chemical Technology, University of Pardubice, Studentská 573, 532 10 Pardubice, Czech Republic.
Contacts:
a)
b)
c) Corresponding author:
d)
e)
Abstract:
Smart materials, including magnetorheological (MR) fluids, have been emerging in a wide range of applications. Ferrite-based paint pigments, nickel ferrite and barium ferrite, are tested as a dispersed phase of a MR fluid in this study. The anticorrosive properties of both pigments have been previously reported, as such, they have a potential to be applied as hybrid corrosion-protection and magneto-active paint. Both pigments were characterized by scanning electron microscopy, X-ray diffraction spectroscopy, and their magnetic properties were evaluated by vibrating-sample magnetometer. Finally, the MR properties were evaluated by rotational rheometer employed with a magneto-cell. The MR performance of both ferrites was compared, with the nickel ferrite as the superior of the two. Thus, the studied pigments have the potential to be applied as a hybrid magneto-active anticorrosive paint.
Michal Sedlačík | Tomas Bata University in Zlín | Zlín, Czech Republic
Shear Stability of Base Fluids for Environmentally Acceptable Lubricants for Stern Tube Application
Autors:
Marek Večeř a) and Simona Krčková b)
Affiliation:
Centre of Chemical Engineering, VSB – Technical University of Ostrava, 17. listopadu 2172/15, 708 00, Ostrava-Poruba, Czech Republic.
Contacts:
a) Corresponding author:
b)
Abstract:
Legislative restrictions exist on using mineral oils for loss lubrication of marine propellers. A key question is finding a functionally suitable and economically acceptable substitute for mineral lubricants. The answer will make it possible to fundamentally limit the impact of international shipping on the marine ecosystem. This work presents the results of an experimental study of four types of base fluids and the influence of seawater on their properties. The results show that base fluids based on vegetable oils have a high viscosity index, i.e., their viscosity changes slightly with temperature. However, at the same time, they contain a relatively large amount of free fatty acids, which promote corrosion (high total acid number). The viscosity of saturated and unsaturated synthetic esters is more temperature dependent. However, their total acid number is significantly lower, making them suitable candidates for these applications.
Marek Večeř | VSB – Technical University of Ostrava | Ostrava, Czech Republic
RHEOLOGY OF POLYMERIC MATERIALS IV
(Chairman: Christopher W. Macosko)
11:00 – 11:30
Novel Combined Methods in Rheology: Rheo-NMR, Rheo-IR and Rheo-Dielectric to Correlate Length and Time Scales
Autors:
K. Ratzsch 2), C. Fengler 3), C. O. Klein 1), R. Figuli 1), N. Radebe 4), S. Nie 5), M. Heck 1), C. Iacob 1) and M. Wilhelm 1, a)
Affiliations:
1) Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
2) KIT, now Bruker Biospin GmbH, Ettlingen, Germany.
3) KIT, now Freudenberg Technology Innovation, Weinheim, Germany.
4) KIT, now SABIC, Limburg, Netherlands.
5) KIT, now Goodyear Belgium SA.
Contact:
a) Corresponding author:
Abstract:
Rheology provides access to the flow properties of soft matter and can establish the interplay of molecular structure and mechanical properties. In order to develop advanced materials, it is important to have a molecular understanding over a broad length and time scale. Our research focus is to develop novel combined rheological techniques, that can in situ monitor molecular dynamics or chemical functional groups, that can be directly correlated to the macroscopic mechanical responses. We have developed several globally unique combinations where rheology and spectroscopic methods are combined to investigate the macroscopic mechanical properties from a molecular point of view. A unique combination of rheology and low-field time domain 1H NMR (TD-NMR) was developed by implementing a compact 25 MHz NMR magnet into a DHR-3/ARES-G2 rheometer. This Rheo-NMR device can quantify segmental motion of polymer chains via transverse relaxation times (T2) while simultaneously performing advanced rheological protocols. We used this device e.g. in rubber science to test whether varying vulcanization procedures of natural rubbers monitoring the polysulfidic crosslinks. The Rheo-NMR device was further used in hydrogel synthesis to study the impact of crosslinker concentration (DC) during the aqueous crosslinking copolymerization of acrylic acid and N,N’-methylenebis(acrylamide). To correlate chemical structure formation during polymerization and the in situ correlation towards mechanical properties, IR spectroscopy was correlated to mechanical characterization during hydrogel formation. In the later stage of the chemical reaction a scaling exponent of 10 was determined for G’ as a function of chemical bond formation.Another prominent of our own developments in the field of combined techniques is Rheo-BDS (Broadband Dielectric Spectroscopy) for the investigation of short length scale dynamic measurements. By using anionic polymerization of isoprene derivatives, we could cover both via dielectric spectroscopy and rheology applying time temperature superposition more than 30 decades in frequency space.
Manfred Wilhelm | Karlsruhe Institute of Technology (KIT) | Karlsruhe, Germany
11:30 – 12:00
Modification of Rheological Responses under Elongational Flow at Non-Isothermal Condition
Autors:
Masayuki Yamaguchi 1, a), Jiraporn Seemork 1, b), Panitha Phulkerd 1, c) and Mohd Amran Bin Md Ali 1, 2, d)
Affiliations:
1) School of Materials Science, Japan Advanced Institute of Science and Technology 1-1 Asahidai, Nomi, Ishikawa 923-1292 JAPAN.
2) Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka 76100 Durian Tunggal, Melaka, MALAYSIA.
Contacts:
a) Corresponding author:
b)
c)
d)
Abstract:
Rheological responses under elongational flow at non-isothermal condition are significantly important for actual polymer processing. Drawdown force, defined as a force required to stretch a molten polymer, was evaluated as the non-isothermal rheological response using polypropylene (PP) in this study. It was found that the die length affected the drawdown force, which was pronounced for a system having a long relaxation time. The prompt crystallization after passing through a long die would be responsible for this phenomenon. Furthermore, the addition of a nucleating agent was quite effective to increase the drawdown force, at which the shape of a nucleating agent has to be considered. The accelerated crystallization by the addition of a fibrous nucleating agent resulted in the pseudo shish-kebab structure, leading to high modulus in the flow direction. Finally, the addition of a low-viscous acrylate polymer was found to enhance the drawdown force of PP. Due to the prompt solidification of the acrylate polymer under a rapid cooling condition, the dispersions acted as rigid fibers before the crystallization of PP. These modification methods will be available to improve the processability at various processing operations at which a molten polymer is stretched at non-isothermal condition.
Masayuki Yamaguchi | Japan Advanced Institute of Science and Technology | Nomi, Japan
12:00 – 13:30
Lunch & Exhibition
NON-NEWTONIAN FLUID MECHANICS
(Chairman: Manfred Hermann Wagner)
13:30 – 14:00
Computational Modelling of the Selective Laser Sintering Process
Autors:
João Castro a), João Miguel Nóbrega b) and Ricardo Costa c)
Affiliation:
Institute for Polymers and Composites, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal.
Contacts:
a)
b) Corresponding author:
c)
Abstract:
Additive Manufacturing (AM) has increased in popularity in numerous important and demanding industries due to the capability of manufacturing parts with complex geometries and reduced wastage. As one of its most popular techniques, selective laser sintering (SLS) is sought after by several industries that aim to replace conventional and more expensive processes. However, the SLS process is intrinsically complex due to the various underlying multi-physics phenomena and more studies are needed to obtain more insights about it. This has resulted in many academical interests to optimize the process and allow it to achieve industrial standards. Most of these optimization attempts are performed through experimental methods that are time-consuming, expensive and do not always provide the optimal configurations. This has led researchers to resort to computational modelling, aiming at better understanding the process to anticipate and fix the defects. The main objective of the present work was to develop a computational model capable of simulating the SLS process for polymeric applications, within an open-source framework, at particle length scale. Since distinct approaches are required for accurately simulating each step of the SLS process, different numerical methods were employed to develop a tool capable of studying the impact, in a representative section of the powder bed, of the physical parameters that can be adjusted in the process. The developed work comprises several steps, starting with an extensive study of the theoretical aspects of the SLS process, which aimed at the acquaintance with the underlying phenomena, process unwind, its parameters and their influence, as well as evaluating the existing limitations and challenges. This step was then followed by a detailed analysis of the most common employed models to represent the major phenomena and of the accuracy level of the approaches, based on the employed simplifications. A set of computational tools was then assessed and their built-in models were selected, when possible, according to the precedent literature review. Lastly, various tests were carried to obtain an experimental qualitative validation of the used code, to assure that the undetaken approach was adequate to simulate the process. The achieved developments represent a significant advance towards the detailed SLS process simulation. With the use of open-source software (LIGGGHTS e OpenFOAM), several studies were performed on a realistic powder bed section and, despite the absence of enough and more detailed experimental data, the simulation results are in agreement with the ones used for comparison. Overall, the accomplished work allowed to conclude that the employed tools constitute a great potential to study, in detail, the SLS process and its parameters influence and, therefore, contribute to its optimization.
João Miguel Nóbrega | University of Minho | Guimarães, Portugal
14:00 – 14:30
Challenges in Nano-Structured Fluid Flows for Assembly into Hierarchical Biomaterials
Autors:
Roland Kádár 1, 2, a), Ann Terry 3, b), Kim Nygård 3, c), Tiina Nypelö 2, 4, 5, d), Gunnar Westman 2, 5, e), Sylwia Wojno 1, 2, f), Reza Ghanbari 1, 3, g), Mina Fazilati 1, 5, h), Marko Bek 1, i) and Amit Kumar Sonker 1, 2, 3, j)
Affiliations:
1) Chalmers University of Technology, Department of Industrial and Materials Science, 412 96, Göteborg, Sweden.
2) Wallenberg Wood Science Centre (WWSC), Chalmers University of Technology, 412 96, Göteborg, Sweden.
3) MAX IV Laboratory, Lund University, 22484, Lund, Sweden.
4) Chalmers University of Technology, Department of Chemistry and Chemical Engineering, 412 96, Göteborg, Sweden.
5) Aalto University, Department of Bioproducts and Biosystems, 02150, Espoo, Finland.
Contacts:
a) Corresponding author:
b)
c)
d)
e)
f)
g)
h)
i)
j)
Abstract:
Hierarchical biomaterials have their place in the context of developing novel material systems particularly in the framework of sustainability. The key to their development is in controlling their assembly into hierarchical orders at various lengthscales. Thus, flow can be an asset in e.g. controlling orientation, however, resolving the hierarchical orientation dynamics of such systems remains a challenge. We focus here mainly on cellulose nanocrystals water-based suspensions, however, the outline is representative of numerous nanostructured fluids.
Roland Kádár | Chalmers University of Technology | Göteborg, Sweden
14:30 – 15:00
Refreshment & End of the conference