Manfred Hermann Wagner (born 1948) is the author of

Wagner model Wagner model is a rheological model developed for the prediction of the viscoelastic properties of polymers. It might be considered as a simplified practical form of the Bernstein-Kearsley-Zapas model. The model was developed by German rheologist ...

and the molecular stress function theory for

polymer A polymer (; Greek ''poly-'', "many" + '' -mer'', "part") is a substance or material consisting of very large molecules called macromolecules, composed of many repeating subunits. Due to their broad spectrum of properties, both synthetic and ...

rheology. He is a Professor for Polymer engineering and

Polymer physics Polymer physics is the field of physics that studies polymers, their fluctuations, mechanical properties, as well as the kinetics of reactions involving degradation and polymerisation of polymers and monomers respectively.P. Flory, ''Principles of ...

at the

Technical University of Berlin The Technical University of Berlin (official name both in English and german: link=no, Technische Universität Berlin, also known as TU Berlin and Berlin Institute of Technology) is a public research university located in Berlin, Germany. It was ...

. Manfred was born in Stuttgart, Germany in 1948. He obtained his PhD in

Chemical engineering Chemical engineering is an engineering field which deals with the study of operation and design of chemical plants as well as methods of improving production. Chemical engineers develop economical commercial processes to convert raw materials in ...

at the ''Institute for Polymer Processing'' of Stuttgart University. He worked as a post-doc in Polymer Physics under Joachim Meissner at the Eidgenössische Technische Hochschule in Zurich, and in the Plastic industry, then he returned to Stuttgart University in 1988 as Professor for Fluid Dynamics and Rheology. In 1998–1999, he was ''Dean of the Faculty of Chemical Engineering and Engineering Cybernetics'' of Stuttgart University. In 1999, he moved to ''Technical University of Berlin''. His works include the

constitutive equation In physics and engineering, a constitutive equation or constitutive relation is a relation between two physical quantities (especially kinetic quantities as related to kinematic quantities) that is specific to a material or substance, and appr ...

s for polymer melts, the application of rheology to the processing of polymers, and structure-property relationships for polymers. The focus of his work on

rheology Rheology (; ) is the study of the flow of matter, primarily in a fluid (liquid or gas) state, but also as "soft solids" or solids under conditions in which they respond with plastic flow rather than deforming elastically in response to an appli ...

is the field of non-linear shear and elongational behavior of

melts and effects of polydispersity, branching and blending on melt behavior. The outstanding point associated with Wagner's work is the relative simplicity of the structural picture of the polymer chain and its respective mathematical formulation. His latest contribution to the constitutive modeling, the MSF (Molecular Stress Function) theory, assumes a microstructure-based damping function (developed by himself in the late 1970s) that modifies the tube model of Doi and Edwards by considering the tube diameter to change with deformation. This assumption overcomes the most important disadvantage of the DE theory and produces excellent predictions consistent with the picture of the polymer chain. He has published to date over 100 scientific papers. In 1981, he received the annual award of the British Society of Rheology . The Institute of Materials, London, awarded him the Swinburne Award 2002. Wagner was the President of the ''German Society of Rheology'' 1991–2003, and he is Secretary of the ''European Society of Rheology'' since 1996. Until 2008 Wagner and Rolon-Garrido are studying the constitutive equations model to improve the rheology model at Polymertechnik/Polymerphysik at the TU-Berlin. Other rheological projects as polymer/additive interactions are being studied by Wagner and Marco Müller.

Selected papers

Modeling non-Gaussian extensibility effects in elongation of nearly monodisperse polystyrene melts V.H. Rolon-Garrido, M. H. Wagner with C. Luap, T. Schweizer
Journal of Rheology 50(3)27–340 May/June 2006
prediction of transient and steady-state elongational viscosity of nearly monodisperse polystyrene melts, with S. Kheirandish and O. Hassager
Journal of Rheology, 49:1317–1327 (2005)"
"Exponential shear flow of branched polyethylenes in rotational parallel-plate geometry, with V.-H. Rolon-Garrido, K. Chai
Rheologica Acta, 45:164–173 (2005)"
"Modeling strain hardening of polydisperse polystyrene melts by molecular stress function theory, with S. Kheirandish, K. Koyama, A. Nishioka, A. Minegishi and T. Takahsahi
Rheologica Acta, 44:235–243 (2005)"
"Quantitative analysis of melt elongational behavior of LLDPE/LDPE blends, with S. Kheirandish and M. Yamaguchi
Rheologica Acta, 44:198–218 (2005)"
"Relating rheology and molecular structure of model branched polystyrene melts by molecular stress function theory, with J. Hepperle and H. Münstedt
Journal of Rheology, 48:489–503(2004)"
"Quantitative assessment of strain hardening of low-density polyethylene
melts by the molecular stress function model, with M. Yamaguchi and M. Takahsahi">low-density polyethylene">"Quantitative assessment of strain hardening of low-density polyethylene
melts by the molecular stress function model, with M. Yamaguchi and M. Takahsahi Journal of Rheology, 47:779–793(2003)"
"The molecular stress function model for polydisperse polymer melts with dissipative convective constraint release, with P. Rubio and H. Bastian
Journal of Rheology, 45:1387–1412(2003)"
"Determination of elongational viscosity of polymer melts by RME and Rheotens experiments
Journal of Rheology, 41:316–325(2002) "
"The strain-hardening behaviour of linear and long-chain-branched polyolefin melts in extensional flows, with H. Bastian, P. Hachmann, J. Meissner, S. Kurzbeck, H. Münstedt and F. Langouche
Rheologica Acta, 39:97–109 (2000)"
"LDPE melt rheology and the pom–pom model, with P. Rubio

Journal of Non-Newtonian Fluid Mechanics A journal, from the Old French ''journal'' (meaning "daily"), may refer to: * Bullet journal, a method of personal organization *Diary, a record of what happened over the course of a day or other period *Daybook, also known as a general journal, a ...

, 92:245–259 (2000)"
"The rheology of the rheotens test, with A. Bernnat and V. Schulze
Journal of Rheology, 42:917–928(1998)"
"Nonlinear viscoelastic characterization of a linear polyethylene (HDPE) melt in rotational and irrotational flows

, 79:283–296 (1998)"
"A constitutive analysis of uniaxial, equibiaxial and planar extension of a commercial linear high-density polyethylene melt, with P. Ehrecke, P. Hachmann and J. Meissner
Journal of Rheology, 42:621–638(1998)"
"Dynamics of polymer melts in reversing shear flows, with P. Ehrecke

, 76:183–197 (1998)"
"A note on the melt strength of liquid crystalline polymer, with Th. Ixner and K. Geiger
Journal of Rheology, 41:1087–1093(1997)"
"Damping functions and nonlinear viscoelasticity—a review

, 68:169–171 (1997)"
"The origin of the C2 term in rubber elasticit
Journal of Rheology, 38:655–679(1994)"
"Rubbers and polymer melts: Universal aspects of nonlinear stress–strain relations, with J. Schaeffer
Journal of Rheology, 37:643–661(1993)"
"Nonlinear strain measures for general biaxial extension of polymer melts, with J. Schaeffer
Journal of Rheology, 36:1–26(1992)"
"A constitutive analysis of extensional flows of polyisobutylene, with A. Demarmels
Journal of Rheology, 34:943–958(1990)"
"Constant force elongational flow of a low-density polyethylene melt—experiment and theory"

, with T. Raible, S. E. Stephenson and J. Meissner11:239–256 (1982)
"The Irreversibility Assumption of Network Disentanglement in Flowing Polymer Melts and its Effects on Elastic Recoil Predictions, with S. E. Stephenson
Journal of Rheology, 23:489–504(1979)"
"A constitutive analysis of uniaxial elongational flow data of low-density polyethylene melt"

, 4:39–55 (1978)

External links

*
Wagner's TU Berlin Homepage
* {{DEFAULTSORT:Wagner, Manfred 1948 births Living people 20th-century German mathematicians 20th-century German physicists Polymer scientists and engineers Rheologists Members of the European Academy of Sciences and Arts 21st-century German mathematicians Academic staff of the Technical University of Berlin 21st-century German physicists