62nd International
Intensive Short Course
on
POLYMER RHEOLOGY
and
EXTRUSION

Program Outline

Note: English will be used in all lectures and course notes. However, questions may be asked in German, French, Spanish, or Greek. Dr. Vlachopoulos will translate the questions and will give the answers in English for the benefit of everyone.

Thursday, April 10, 2008

9:00 - 9:30 -- Welcome & Registration

9:30 - 12:30 -- Introduction to Rheology

Unusual rheological phenomena exhibited by polymer solutions and melts. The importance of rheology in polymer processing. Viscosity, melt flow index and melt strength, and their relation to molecular structure. The role of temperature, pressure, additives, and fillers. The Dow Rheology Index for Insite technology polyolefins. Rheology of metallocene polymers.

12:30 - 14:00 -- Lunch

14:00 - 17:30 -- Rheology for Process Optimization

Shear and normal stresses. Viscoelasticity. Stress relaxation. Extensional viscosity. G' and G" measurement and significance in polymer characterization. The role of rheology in mixing and blending. Rheological modifications by blending certain polymers, such as LLDPE and LDPE. Determination of MWD from rheological measurements. Predicting processability from rheology. Viscosity of suspensions. Rheology of wood plastics composites (WPCs). Rheology of some nanocomposites. Problem solving using rheology.

Friday, April 11, 2008

9:00 - 12:30 -- Melt Flow Through Dies, Extrudate Swell, Die Lip Build-up, Sharkskin and Melt Fracture

Unidirectional and multidimensional flows. Pressure drop and frictional heating (viscous dissipation). The mechanisms responsible for extrudate swell. Die lip build-up (drool) causes and remedies. Relation to molecular structure. Causes for the onset of sharkskin and gross melt fracture. The effects of adhesion and slip. The role of additives and processing aids. Recent theories and their application to process improvement.

12:30 - 14:00 -- Lunch

14:00 - 17:30 -- Extrusion and Troubleshooting

Principles of solids conveying, melting, mixing and melt pumping in single screw extrusion. Simple formulas for calculation of Throughput, Power and Torque. Screw design considerations and review of modern designs. Conventional versus barrier screws. Screws with mixing elements. Dies for extrusion and coextrusion. Surging, gels, screw and barrel wear, the role of moisture, interfacial instabilities, weldlines, MD Flow lines, and thickness non-uniformities. Systematic fault diagnosis and troubleshooting.

Lecture Notes

Each participant will receive a copy of the annually updated book of lecture notes on POLYMER RHEOLOGY AND EXTRUSION. This fact-filled book includes copies of the presentation slides, theory, detailed derivations of several important equations and numerous worked-out problems. It is highly recommended for follow-up reading either as a quick information sourcebook or for in-depth study. It is easy to follow with the mathematical level kept to a minimum. Several key references are also given for persons wishing to continue upgrading their knowledge and understanding. It shows how to do simple calculations of shear rate, shear stress, pressure drop, temperature rise due to viscous dissipation, Rabinowitsch and Bagley corrections in capillary viscometry, wall slip velocity, flow throughput in extruders and much more. Whether you want practical problem solving information and troubleshooting tips or you want to understand the importance of recent developments, you will find this book indispensible.

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