Polymer Processing Plasticizing In Single Screw Extruders Gasparcunha A by Gaspar-cunha A. 9788379474608, 8379474600 instant download after payment.

In polymer processing one of the most important steps is plasticization, which consists of transforming the raw material, initially in the solid state (in the form of granules or powder), into a viscous fluid. In the plastics processing industry, practically all polymers go through a plasticization process, where one or more screws force the solid material to pass through heated areas of a cylinder where it melts [TAD 70, RAU 86, AGA 96, WHI 90, STE 95, TAD 06, GAS 09]. This thermomechanical process occurs in injection molding, blow-molding, single-screw and twin-screw extrusion and even the raw material (in sheet form) used in the thermoforming is manufactured using an extruder.
Due to the unique characteristics of polymers, especially their thermal, physical and rheological properties, the study of the plasticization process is not trivial, and it is therefore necessary to study the influence that these properties may have on the performance of the process. On the other hand, the geometry of the system also plays an important role in this same performance, since, of course, it will not be indifferent to use a single screw extruder, with or without barrier screws and/or mixing sections, or a twin-screw extruder, counter or co-rotating, or even multi-screw extruders. Finally, it is also important to mention that the processing conditions defined in the machine have a decisive influence on the plasticization performance [TAD 70, RAU 86, WHI 90].
From the above, it can be said that the performance of a plasticization process depends on variables related to the properties of the polymers, the geometry of the system and the processing conditions. In order to develop methodologies capable of predicting the behavior of polymer plasticization systems, scientific, experimental and theoretical studies were carried out that allowed to relate the process variables to their performance, thus enabling the development of mathematical models, later transformed into computational models, capable of helping the Polymer Engineer to predict the behavior of the systems [TAD 70, RAU 86, WHI 90, O'BR 92, GAS 09].
This text intends to present the mathematical models developed for the calculation of the performance predictions of single-screw extruders (including barrier screws, mixing sections and grooved cylinders) according to the properties of the polymers, the geometry of the system and the operating conditions. It is also intended that these notes serve to support the Polymer Processing Engineering courses. In this sense, in the following chapters the basic concepts necessary to understand the process, the relevant properties, and how they can be quantified in the models presented, and the mathematical models developed will be presented. In the final part of some chapters, practical exercises will be proposed.