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Polymer TechnologyChair: Han Meijer
Faculty:
van Breemen,
Govaert,
Hütter,
Meijer,
Peters,
Schreurs,
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Press here for a list of all group members and other details about the programme.
Press here for current research projects.
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The research is aimed at bridging the gap between science and technology in the area of polymer processing and design, through the use of experimental and computational tools in the modeling of the full thermo-mechanical history of material (elements) during their formation, processing and final design, to quantitatively predict properties of processed objects |
Structure-Property and Constitutive Modeling
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The research focuses on the development of new polymeric systems with optimal mechanical properties (toughness/strength/durability). To achieve this goal it is required that modeling of the macroscopic response of the polymeric material is based on its molecular and microscopic structure, as on those length scales materials can be controlled. This length-scale bridging is achieved by
- use of new, experimentally validated constitutive equations that capture the important features of the polymers' intrinsic deformation behaviour
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homogenisation techniques based on representative volume elements with periodic boundary conditions (multi-level FEM) that are employed to analyse the macroscopic mechanical response.
The three-dimensional non-linear viscoelastic constitutive equations are derived and improved on the basis of experimental observations and include yield, intrinsic strain softening, strain hardening and the important dependence on strain rate and temperature. New developments include the assessment of model parameters on a microscale using indentation techniques, and a numerical tool that can effectively predict the development of mechanical properties during processing of glassy polymers. Subsequently, the macroscopic response of heterogeneous polymeric systems is predicted, based on the micro-deformation. In determining the intrinsic properties of polymeric materials, a distinct length scale is experienced that shows that thin films behave different as compared to the bulk. Given the importance of thin films in modern electronic devices, e.g. poly-LEDs (light emitting diodes), LCD's (liquid crystal displays) and solar cells are based on thin films, special attention is paid to their characterization and constitutive modeling. New routes are explored to obtain specific structures of commonly brittle polymers that display a dramatic increase in their strain to break.(Info: Dr. Leon Govaert).
- Structure-Property Relations and Constitutive Modelling of Amorphous Polymers
- Structure-Property Relations and Constitutive Modelling of Semi-Crystalline Polymers
- Multi-scale mechanics of Polymers
- Micro-Wear of Polymers
Key publications- H.E.H. Meijer, L.E. Govaert, Mechanical performance of polymer systems: The relation between structure and properties,
Prog. Polym. Sci., 30(8), 915-938, (2005)
- L.E. Govaert, T.A.P. Engels, E.T.J. Klompen, G.W.M. Peters, H.E.H. Meijer, Processing-induced properties in glassy polymers: development of yield stress in polycarbonate,
International Polymer Processing, XX(2), 170-177, (2005)
- B.A.G. Schrauwen, L.C.A. van Breemen, A.B. Spoelstra, L.E. Govaert, G.W.M. Peters, H.E.H. Meijer, Structure, deformation and failure of flow-oriented semi-crystalline polymers,
Macromolecules, 37(23), 8618-8633, (2004)
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Surface Mechanics and Microfluidics
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Thin layers, surfaces and coatings are of great importance in different kinds of engineering applications. Nonetheless, the principles of friction and wear are still poorly understood. Analogously, the properties of thin layers and surfaces are different from those in the bulk materials, and these differences are equally ill-understood. In this new starting topic we attempt to better characterize and understand these properties for polymers and metals, and combinations thereof. The methods employed in this research are optical microscopy, environmental scanning electron microscopy (ESEM and high-resolution SEM), orientation imaging microscopy (OIM) in combination with in-situ loading, nano-indentation techniques, lateral force measurements, single-asperity experiments on flat and well-defined surfaces, JKR techniques to study the origins of adhesion and, finally, molecular modeling techniques.Similarly, in microfluidics the analyses are different from those of the bulk and sometimes we can make use of these scale effects. We study the scale effects in solid mechanics, in close cooperation with theme 4, and of fluid mechanics, in close cooperation with theme 3. (Info: Prof. Jaap den Toonder).
- Nano-indentation of Polymers
- Micro-Tribology of Polymers
- Chaotic Mixing in Micro-Channels
- Active Surfaces in Micro-Fluidics
Key publications |
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