COROTATING

FIG. 18-50 Intermeshing corotating twin screw extruder (a) drive motor, (h) gearbox, (c) feed port, (d) barrel, (e) assembled rotors, (f) vent, (g) barrel valve, (h) kneading paddles, ( ) conveying screws, (/) splined shafts, (k) blister rings, (APV Chemical Machinery, Inc.)... 

Prior to blending, the LCP was dried at 155°C for 5 h. The melt blending of the materials was carried out with a Berstorff ZE 25 x 33D corotating twin-screw extruder at a melt temperature of 290°C, with a screw speed of 200 rpm, and an output of 6.4 kg/h. The extrudate was immediately quenched in a water bath and repelletized. 

With the growth of plastic use in containers and packages, requirements to make them more compatible or useful resulted in new developments occuring and continue to occur. The two major approaches for providing permeability resistance in plastic containers involve chemically modifying the plastics surfaces and, more important from a marketing standpoint, the use of barrier plastics with nonbarrier types to meet cost-to-performance requirements. This is achieved through coextrusion, coinjection, corotation, and other such processes (Chapter 8). 

Example 3. Hydrolysis in an Extruder.69 PET reactive extrusion experiments were carried out on a 25-mm Berstorff ZE25 corotating twin-screw extruder with a barrel length-to-screw ratio of 28 1. The extruder consisted of six barrel sections equipped for heating, cooling, and controlling the temperature of each section of the extruder. Initially reaction extrusion of PET and water was performed with cold water at room temperature injected into the extruder. Typical operating conditions were reaction temperatures of 230-265° C, extruder speeds... 

Cornils B (1999) Modern Solvent Systems in Industrial Homogeneous Catalysis. 206 133-152 Corot C, see Idee J-M (2002) 222 151-171... 

Idee J-M, Tichkowsky I, Port M, Petta M, Le Lem G, Le Greneur S, Meyer D, Corot C (2002) lodiated Contrast Media from Non-Specific to Blood-Pool Agents. 222 151-171 Igau A, see Majoral J-P (2002) 220 53-77 Imamoto T, see Crepy KVL (2003) 229 1-40 Iwaoka M, Tomoda S (2000) Nucleophilic Selenium. 208 55-80... 

These two-phase polymers are generated in an optimized single-stage process using a corotating, close-intermeshing, twin-screw extruder. 

Corotating TSEs are widely applied in the compounding of thermoplastics. The extmder consists of two screws which intermesh each other. The screw concept consists of modules with different screw elements. Eigure 35.26 shows typical examples of screws which are applied in twin-screw extmsion. Eigure 35.27 shows typical screw elements which have been used in TSE applications in mbber compounding. A few attempts to apply corotating TSEs into mbber mixing... 

FIGURE 35.26 Typical screw configurations for corotating twin-screw extmders (TSEs). 

FIGURE 3S.27 Typical screw elements as applied in corotating twin-screw extruders (TSEs). 

Idee JM, Pines E, Prigent P, Corot C. Allergy-Uke reactions to iodinated contrast agents. A critical analysis. Fundam Clin Pharmacol 2005 19 263-281. 

Corotational flows distribute material better than counterrotational flows. 

Muller, K., Skepper, J.N., Posfai, M., Trivedi, R., Howarth, S., Corot, C., Lancelot, E., Thompson, P.W., Brown, A.P., and Gillard, J.H. (2007) Effect of ultrasmall superparamagnetic iron oxide nanoparticles (Ferumoxtran-10) on human monocyte-macrophages invitro. Biomaterials, 28 (9), 1629-1642. 

The Darwin mission will not be carried out until the middle of the next decade. However, the COROT (Convection, Rotation and Planetary Transits) telescope was launched from the Baikonur cosmodrome in December 2006. The satellite, which weighs 630 kg, circles the Earth at a height of about 900 km in a polar orbit. The mission is planned to last 21/2 years, and more than 120,000 stars are to be observed. 

The discovery of planets outside our solar system, using the transit method. For the first time, the search will be directed particularly towards planets which are only slightly larger than the Earth. The first, Corot-Exo-lb, was discovered in April 2007. 

The COROT mission is French-led and involves several European partners as well as one in Brazil. 

The start of NASA s Kepler mission is planned for February 2009 and has goals similar to those of the COROT project, though rather more ambitiousiit is intended to determine the percentage of terrestrial and larger planets there are in or near the habitable zone of a wide variety of stars, and also to determine the distribution of sizes and shapes of the orbits of these planets. 

Casali, C. Janier, M. Canet, E. Obadia, J. F. Benderbous, S. Corot, C. Revel, D. Academic Radiology 1998, 5 Suppl. 1, S214-S218. 

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