Ing Ind - Inf (Mag.)(ord. 270) - MI (491) MATERIALS ENGINEERING AND NANOTECHNOLOGY - INGEGNERIA DEI MATERIALI E DELLE NANOTECNOLOGIE
091605 - PRINCIPLES OF POLYMER PROCESSING
The course aims at illustrating the application of continuum mechanics to model thermoplastic polymer processing and apply them to the processing technologies most commonly adopted for this class of materials.
A second goal is to illustrate the effects of forming process on polymers structure and their effect on polymer performance in the final applications.
Risultati di apprendimento attesi
After attending the course and after the final exams the students will:
- know and understand how to apply the mass, momentum and energy conservation principles along with the proper constitutive equation to model simple flow cases;
- know and understand the different possible constitutive behaviors of polymeric solution and melts;
- be able to select the costitutive equation appropriate to each considered case;
- know and understand the extrusion process;
- be able to predict the effects of screw geometry, process conditions, and fluid behavior on the working point of an extruder;
- know and understand the post extrusion processes and their effects to final product performance;
- know and understand the injection molding process;
- be able to estimate the effects of mold geometry, process conditions, and fluid behavior on injection molding process and outcomes;
- be able to autonomously apply the previous knowledge to model complex cases and answer open ended questions.
Basics - An outline of continuum mechanics: concept of a continuum, stress, deformation and deformation rate tensors in a continuum, mass, momentum and energy conservation in solids and fluids; boundary conditions.
Rheology - Phenomenology and description of the newtonian, non-newtonian and viscoelastic behaviour. Simple model flows of newtonian and non-newtonian melts and solutions.
Extrusion - Plasticating extruder: conveying and melting of the solid pellet. Metering extruder: modelling of the flow of a Newtonian and non-newtonian fluid in isothermal and adiabatic condition; discussion of the imposed simplifications; optimal design. Die forming: modelling and design. Die swell; melt instabilities and fracture.
Post extrusion forming - Fiber spinning, Film Blowing
Injection molding - Description and analysis of injection moulding; isothermal newtonian and non-newtonian flow into a cavity; viscous heating in a runner; effects of pressure dependent viscosity; runner and cavity combination; viscous heating in a cavity flow; effect of heat transfer to the cavity walls; cooling of a cavity without flow; shrinkage during cooling and packing; thermal stresses during cooling.
A background of ODE and PDE solving is required.
A background of fluid mechanics and polymer science and technolgy is suggested. However, the basic concepts of these disciplines are presented during the course.
Modalità di valutazione
The examination will consist in an oral discussion on two/three written assignments assigned each student during the course.
The assignments will present a series of problems, some of which with multiple solutions or open solutions. They are aimed at testing:
i) the student's understanding of the course topics;
ii) her/his ability to critically and autonomously apply the acquired knowledge to cases not discussed in class;
iii) her/his ability to present them in a clearly understandable form.
The final oral colloquium will be devoted to the discussion of each student's report and, starting from the report, on the topics of the course.
Middleman, S., Fundamentals of polymer processing, Editore: McGraw-Hill, Anno edizione: 1977, ISBN: 0-07-041851-9
Macosko, C.W., Rheology: Principles, Measurements and Applications, Editore: Wiley-VCH, Anno edizione: 1994, ISBN: 978-0471185758
Tadmor Z., Gogos C., Principles of Polymer Processing, Editore: Wiley-Interscience; 2 edition, Anno edizione: 2006, ISBN: 978-0471387701
Rauwendaal, C., Polymer Extrusion, 4th edition, Editore: Hanser Publications, Anno edizione: 2001, ISBN: 978-1569903216
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Ore di attività svolte in aula
Ore di studio autonome
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