In connection with the 21st annual meeting of thepolymer processing society (PPS-21) the pre-con-ference workshop “Rheology and Processing ofPolymers”, organized by the German Society ofRheology, took place at the PPS-21 conference site“The Westin” in Leipzig on Sunday, June 19, 2005.This workshop was the second of its kind follow-ing the workshop on “Rheology of MultiphaseSystems” held in April 2004 in Berlin. With theseworkshops the German Society of Rheologywants to offer a new way for communicationamongst German rheologists at a time whichsees European and international activities grow-ing. Prof. Dr. H. Münstedt (University of Erlangen-Nürnberg) and Prof. Dr. W. Mielke (Federal Insti-tute for Materials Research and Testing – BAM)organized a meeting that gave a profoundinsight into the rheological basis for polymer pro-cessing covering the whole spectrum of process-ing technologies like extrusion, injection mould-ing or calendering and a broad variety ofpolymeric materials like thermoplasts, elasto-mers and polymer composites. Around 30 peoplefrom all over Europe joined the workshop includ-ing newcomers in the field of rheology as well asparticipants already working in this area. Thisnumber was just the right basis for lively andfruitful discussions.

Seven speakers from universities and com-panies presented their results and ideas to ahighly interested and competent audience ofrepresentatives from academic institutions,industrial companies, instrument manufactur-ers and national laboratories. The 40 minutespresentations followed by 10 minutes for discus-sion offered the possibility to go into detail of asubject and to intensively discuss a topic.

Prof. Dr. H. Münstedt, chairman of the Ger-man Society of Rheology, opened the workshop.He referred to the successful launch of the newseries of annual workshops last year in Berlin, andemphasized the outstanding character of thiskind of seminar which offers the possibility tobroaden and intensify the rheological knowledgein a more focused way than it would be feasibleat big events like the European Conferences onRheology. He took the opportunity to thank Prof.Dr. H-J. Radusch, head of the organizing com-

238 Applied RheologyVolume 15 · Issue 4

Workshop“Rheology and Processing of Polymers”

June 19, 2005Leipzig, Germany

ConferenceReport I

mittee of PPS-21, for the kind invitation to holdthe workshop just before the PPS session on rhe-ology. After his welcome the participants wereasked to introduce themselves and to state theirexpectations. This procedure eased the way toget into contact with each other.

The first lecturer Dr. M. Schmidt from BayerAG (Germany) spoke about the usefulness ofneural networks for the prediction of shear vis-cosity functions. He introduced the software toolDesign- and Processing Properties (DPP) which isused by Bayer Material Science for the predictionof part properties during processing and forapplication. In this software they implementedneural networks, which are effective tools for theidentification and prediction of multidimension-al correlations. The software can be used for theprediction of shear viscosity functions and mod-eling of the influence of temperature, molecularstructure and fillers on the viscosity function.

Prof. Dr. H. Münstedt from the University ofErlangen-Nürnberg (Germany) talked about therole of elongational rheology in predicting someaspect of the processing behavior of polymermelts. He showed that a homogeneous sampledeformation in uniaxial elongational experi-ments due to a pronounced strain hardening cor-relates with a better film homogeneity of blownpolyethylene films and a homogeneous wallthickness of thermoformed beakers from poly-propylene. He explained that the pronouncedstrain hardening behavior and thus the homo-geneous samples deformation is referred to thepresence of long-chain branches within the poly-mer melts. This led to the conclusion, that elon-gational rheology can make a substantial contri-bution to optimize the molecular structure ofpolymers for processes with prevailing elonga-tional components.

Prof. Dr. M.H. Wagner from the TechnicalUniversity of Berlin introduced the RheotensTest. This is a very suitable method to investigatethe elongational behavior of polymer meltsunder process conditions. Using the RheotensTest it is not only possible to determine the meltstrength and drawability which are relevant formany processing operations, but also to calcu-

© Appl. Rheol. 15 (2005) 238–239

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This is an extract of the complete reprint-pdf, available at the Applied Rheology websitehttp://www.appliedrheology.org

This is an extract of the complete reprint-pdf, available at the Applied Rheology websitehttp://www.appliedrheology.org

late the apparent elongational viscosity, fromwhich further interpretations with respect to themolecular structure are possible.

Prof. Dr. R. Schnabel from the University ofHalle-Wittenberg (Germany) talked about mod-eling of the calendering process on base of rheo-logical data. He gave an overview over existingmodels and how they can be used to describe thevelocity field in the calender, the non-isothermalbehavior during cooling and the biaxial stretch-ing which is often combined with a calenderingline.

The afternoon session was opened by Dipl.-Ing. M. Kurte-Jardin from the University of Pader-born who talked about the influence of the wall-slippage on the processing characteristics in asingle-screw extruder. Wall-slippage occurs forsome polymers above the so-called critical shearstress and leads to a significant change of thematerial throughput in the extruder. By the useof different models the influence of wall-slip-page on the flow behavior in the extruder chan-nel is analyzed and compared to the well-knownflow behavior in case of wall-adherence.

Prof. Dr. G. Heinrich from the Leibniz-Insti-tute of Polymer Research Dresden took the audi-ence into the world of elastomers. He showedthat rheology plays also an important role in theprocessing of high-performance elastomers fortire applications. Especially the rheologicalbehavior of different filled elastomers in combi-nation with the dynamic-mechanical testing isused to optimize the composition of the elas-tomers and their tire performance.

The seminar closed with a lecture of Dipl.-Ing. K. Skrodolies from RWTH Aachen. He talked

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about the rheology of fibre reinforced compos-ites and its use for process simulation. Polymermelts filled with long fibres of a length between4.5 to 50 mm are formed into to complicatedshapes by compression moulding. For theprocess simulation a detailed knowledge aboutthe rheological behavior of the filled polymers inshear and elongational flow is necessary. Heintroduced a press-rheometer for the determi-nation of the viscosity of fibre reinforced com-pounds, which was developed at the Universityof Aachen.

Recapitulating the workshop it can be saidthat the audience was very satisfied with the out-come of the seminar. There was enough time forthe speakers to go into detail and to stimulateintense discussions resulting in a fruitfulexchange of ideas. The combination of the pre-sentation of basic knowledge about rheologyand processing for newcomers in the field of rhe-ology as well as the transfer of information aboutnew aspects in this field to those of the audiencewho were already very familiar with the topicwas very successful.

J. StangeInstitute of Polymer MaterialsFriedrich-Alexander-UniversityErlangen-NürnbergMartensstrasse 791058 ErlangenGermanyjens.stange@ww.uni-erlangen.de

Figure 1 (left):Prof. Münstedt begrüsst dieTeilnehmer.

Figure 2:Lebhafte Diskussion in derPause.

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This is an extract of the complete reprint-pdf, available at the Applied Rheology websitehttp://www.appliedrheology.org

This is an extract of the complete reprint-pdf, available at the Applied Rheology websitehttp://www.appliedrheology.org