Rheology of Polymers
Holders: Assist. Prof. Slemenik Perše Lidija
Subject description
Prerequisites:
Non-metallic materials (basics of polymers – thermal properties, mechanical properties, time-dependent properties of polymers and polymer composites); Strength of Materials and Fluid dynamics.
Content (Syllabus outline):
INTRODUCTION: Basic rheological parameters, Material functions in time and frequency domain, Basic flow regimes, Effect of molecular weight on mechanical and rheological properties
RHEOMETRY: Instruments for determination of rheological properties, Geometries of sensor systems, Methods for determination of rheological properties of melts and solids, Calculation of rheological parameters
YIELD STRESS: Engineering examples of polymers with yield stress, Equations for rheological behaviour of materials with yield stress, Determination and prediction of the behaviour of polymers with yields stress
VISCOELASTICITY: Creep and relaxation – relation between stress and strain, Energy absorption, Mechanical models for prediction of viscoelastic behaviour during creep and relaxation, Explanation of the general stress-strain state of viscoelastic materials using material functions; Linear and non-linear behaviour of materials, Practical meaning of linear theory of viscoelasticity, Determination of stress limit
TIME DEPEDENCY of MECHANICAL PROPERTIES: Relaxation time, Thixotropy, Physical aging, Mechanical spectra
EFFECT of TEMPERATURE on RHEOLOGICAL and MECHANICAL PROPERTIES of POLYMERS: Temperature tests, Determination of phase transitions with dynamic moduli, Degradation
RHEOLOGICAL MEASUREMENTS of POLYMER MATERIALS: Selection of the proper rheological method, Interpretation of the results of rheological measurements, Relation of rheological properties with the structure of polymer; Relation of the rheological properties of melt with process parameters of polymer processing, Influence of viscoelastic properties on the polymer product during processing (Dye swell effect, Weisenberg effect, melt fracture, yield stress, ...), Influence of time dependent properties on the performance (mechanical properties) and life-time of polymer products (gears, seals, valves, ...)
SPECIAL APPLICATIONS of RHEOLOGICAL PROPERTIES of POLYMERS in MECHANICAL ENGINEERING – examples
Discussion and summary
Objectives and competences:
Goals: The course objective is to acquaint the students with the rheological and time-dependent behaviour of polymer materials and their composites, and with the material functions describing their behaviour in the time and frequency domains.
Competences:
- understanding the rheological behaviour of liquid- and solid-like polymers and composites,
- understanding the time-dependent behaviour of polymers and composites,
- mastering the research methods, procedures and processes, development of ability to do critical and self-critical evaluations,
- the ability to use the knowledge in the practice,
- the development of communication skills, especially for communication in the international environment,
- cooperativeness, teamwork (in the international environment).
Intended learning outcomes:
Knowledge and understanding
The students attain the knowledge on the rheological behaviour of synthetic and bio-polymeric materials. They understand the specialties of rheological and time-dependent behaviour of polymer melts and solid polymeric structural materials and the advantages offered by these materials in science and engineering. They master the mathematical approaches used to describe the behaviour of time-dependent materials in the time and frequency domain, as well as the prediction of life of products made from these materials.
Usage
The knowledge assimilated in the course will benefit the students in all disciplines of engineering using polymeric materials and corresponding composites. This knowledge is of special importance to technologists and design engineers.
Reflection
The theoretical knowledge acquired in the course and the experience gained in experimental practicum executed in the laboratory environment and partially on real objects in the industrial environment can be transferred directly and used for various research, development and practical purposes in the field of design and processing technologies.
Transferrable skills – related to more than one course
Using the modern professional literature and practical work with modern laboratory, measuring and software equipment.
