Extrusion single-screw

Borgaonkar H. and Ramani K., Stability analysis in single screw extrusion of thermoplastic elastomers using simple design of experiments, Adv. Polym. Technol., 17, 115, 1998. 

Arastoopour, H., Single-screw extruder for soUd state shear extrusion pulverization and method, US patent, 5,704,555, 1998. 

Elucidation of degradation kinetics for the reactive extrusion of polypropylene is constrained by the lack of kinetic data at times less than the minimum residence time in the extruder. The objectives of this work were to develop an experimental technique which could provide samples for short reaction times and to further develop a previously published kinetic model. Two experimental methods were examined the classical "ampoule technique" used for polymerization kinetics and a new method based upon reaction in a static mixer attached to a single screw extruder. The "ampoule technique was found to have too many practical limitations. The "static mixer method" also has some difficult aspects but did provide samples at a reaction time of 18.6 s and is potentially capable of supplying samples at lower times with high reproducibility. Kinetic model improvements were implemented to remove an artificial high molecular weight tail which appeared at high initiator concentrations and to reduce step size sensitivity. 

Extruders are normally classified by their method of construction, i.e. twin screw or single screw and the operating conditions, i.e. cold extrusion or extrusion cooking. Cold extrusion is used to make liquorice and pasta among other products and so is outside the scope of this work. Extrusion cooking, which is defined as heating the product above 100 °C, has many uses. 

The fundamental processes and mechanisms that control single-screw extrusion are presented in Chapters 5 through 8. These processes include solids conveying, melting, polymer fluid flow, and mixing. The analyses presented in these chapters focus on easily utilized functions needed to assess the operation of the single-screw extruder. The derivation of these relationships will be presented in detail in the appendices for those who desire to explore the theory of extrusion in more detail. 

Fig. 2.15. Reactors for producing these materials include batch, continuously vented, tray reactors, twin-screw extruders, and vented single-screw extruders. These production devices will not be covered in this text because they are of more interest to the manufacturing engineer than the extrusion process engineer.

The following section will now focus on experimental methods for determining viscosity and how the viscosity function relates to analyzing single-screw extrusion processes. 

Gogos, C.G., Zafar, M., Sebastian, D., Todd, D.B., Hyun, K. S., and Spalding, M.A., A Device to Study Solids Compaction and Conveying in Single Screw Extrusion, SPE ANTEC Tech. Papers, 40, 288 (1994)... 

Potente, H., Single Screw Exlruder Analysis and Design, Chapter 5 in Screw Extrusion, White, J. L. and Potente, H. (Eds.), Hanser Publishers, Munich (2002)... 

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