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Extrusion Temperature (extrusion + temperature)
Selected AbstractsPreparation of strach-graft-polyacrylamide copolymers by reactive extrusion,POLYMER ENGINEERING & SCIENCE, Issue 10 2003J. L. Willett Graft copolymers of starch and polyacrylamide (PAAm) were prepared by reactive extrusion using a co-rotating twin-screw extruder and ammonium presulfate initiator. Feed rates were 109 g/min to 325 g/min (all components) at a moisture content of 50%, with screw speeds in the range 100 rpm to 300 rpm. Starch/acrylamide weight ratios ranged from 5:1 to 1.3:1. Conversions of acrylamide to PAAm were generally 80% or greater with residence times of 400 seconds or less. Conversion increased with feed rate, suggesting that reaction efficiency was proportional to the degree of fill in the extruder. Grafting efficiencies were in the range of 50% to 80%. PAAm molecular weight increased with increasing acrylamide content, consistent with free radical polymerization kinetics. Extrusion temperature had no significant impact on acrylamide conversion. Graft frequency, as measured by the number of anhydroglucose units per graft, was essentially constant over the starch: acrylamide ratio and temperature range studied. These results show that reactive extrusion offers the potential for rapid production of starch graft copolymers with unsaturated monomers. [source] Investigation of the derived fuel rod formation from auto shredder residue using an extrusion apparatusENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2006Hua-Shan Tai Abstract The objective of this study was to form auto shredder residue,derived fuel (ASRDF) by using an extrusion apparatus, to solve the disposal problems of auto shredder residue (ASR) and to recover the heat value in its combustible content. ASR is the waste material produced by shredding vehicles. In general, these materials contain 20,30% of each vehicle by weight. ASR should be preprocessed into extruded rods before being used for fuel to remove about 20,30% inorganic, incombustible materials and to accommodate easy transportation and storage. The analytical results of ASR indicated the moisture content to be <2%, ash was <20%, and combustibles were nearly 80% by weight. Concentrations of N and S in the ASR were very low, although the chlorine content of ASR was in the range of 1.32,2.79%, which is the main burden of the ASR utilization. The heat content of ASR was about 5000,6000 kcal kg,1 (9000,10,800 BTU lb,1). Particle size had no significant effect on the analytical chemical composition. All the data indicated that ASR had a significant potential use as RDF. Through observations of the appearance and density of the ASRDF rod, we found that better appearance and higher densities could be achieved at higher extrusion temperature and pressure. The heat content of ASRDF was much lower than that of ASR, and it decreased with increasing extrusion temperature and pressure. The reasons for the better appearance, higher densities, and heat loss on the conditions of higher extrusion temperature and pressure may be explained by the proposed die swell ratio and skin,core effect. © 2006 American Institute of Chemical Engineers Environ Prog, 2006 [source] The optimization of the extrusion process when using maize flour with a modified amino acid profile for making tortillasINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2006Jorge Milán-Carrillo Summary Maize with a modified amino acid profile, i.e. greater amounts of lysine and tryptophan than normal, is known as ,quality protein maize' (QPM). The objective of this work was to find the best combination of extrusion process variables to produce QPM flour for making tortillas. QPM grits were mixed with lime and water and had a moisture content of 28%. The single screw extruder operation conditions were selected from factorial combination of three process variables: extrusion temperature (ET, 70,100 °C), lime concentration (LC, 0.1,0.3% of the maize weight) and screw velocity (SV, 80,250 rpm). Response surface methodology was used as an optimization technique. In vitro protein digestibility (PD); total colour difference (,E) of the flours, and tortilla puffing (TP) were chosen as response variables. A graphical method was used to obtain maximum PD, TP and minimum ,E. The optimum combination of process variables was: ET = 85 °C/LC = 0.21%(w/w)/SV = 240 rpm. Tortillas from QPM flour had similar chemical composition, physicochemical and sensory properties to tortillas from commercial nixtamalized maize flour; however, the former had the highest (P , 0.05) available lysine content and were therefore better nutritionally. [source] Reactive extrusion to synthesize intumescent flame retardant with a solid acid as catalyst and the flame retardancy of the products in polypropyleneJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2008Yuan Liu Abstract Reactive extrusion and solid acid catalysis technologies were adopted in the pentaerythritol,melamine phosphate (PER-MP) reaction to synthesize intumescent flame retardant, melamine salt of pentaerythritol phosphate (MPP), which was applied in flame retardant polypropylene (PP). This environment-friendly synthesis method provided a solution to the problems of conventional methods. On one hand, reactive extrusion in a twin screw extruder can effectively mix and transfer viscous materials that usually results in a tough stir in a conventional reactor, and achieve a continuous synthesis process. On the other hand, the solid acid, silicotungstic acid (STA) serving as a catalyst, can maintain a satisfactory conversion even with a low extrusion temperature and a short residence time, thus effectively suppressing foaming in the process of the reaction. Furthermore, without removal like other catalysts in general chemical reactions, STA was kept in produced MPP to constitute a synergism flame retardant system, therefore further improved the flame retardancy. LOI and UL94 test showed that the STA-catalyzed MPP (by reactive extrusion) possessed much better flame retardancy in PP when compared with the noncatalyzed MPP (by reactive extrusion), as well as present commercial MPP (by POCl3 method). In our investigation, the catalytic and synergistic effects of STA, as well as the related factors of the reactive extrusion affecting the conversion of the PER-MP reaction, flame retardancy and mechanical performance of the corresponding flame retardant PP, were systematically investigated. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008 [source] THE EFFECT OF EXTRUDED FLOUR AND FERMENTATION TIME ON SOME QUALITY PARAMETERS OF IDLIJOURNAL OF FOOD QUALITY, Issue 1 2000KULWINDER KAUR ABSTRACT The effects on idli characteristics of fermentation time and substituting rice with differing proportions of rice flour extrusion-cooked under different conditions were studied. The specific gravity, pH and viscosity of batter and idli characteristics such as expansion, compression force and sensory attributes were measured and described using regression to fit a response surface analysis. Fermentation time showed the most pronounced effect on specific gravity, pH and aqueous dispersion viscosity of batter and taste scores of idli. Substituting rice flour with extruded rice flour at different levels were observed to have significant effect on expansion and appearance scores of idlis. The textural scores and compression force was significantly affected by extrusion temperature. The formulation containing rice substituted by 30% extruded rice flour extruded at 175C and fermented for 24 h produced idlis with highest expansion and overall acceptability. [source] Morphology development of PC/PE blends during compounding in a twin-screw extruderPOLYMER ENGINEERING & SCIENCE, Issue 1 2007Bo Yin The morphological development of a polycarbonate/polyethylene (PC/PE) blend in a twin-screw extruder was studied using a scanning electron microscope (SEM). The effects of extrusion temperature, viscosity ratio (the ratio of the viscosity of the dispersed phase to that of the matrix), and the screw configuration on the morphology of the PC/PE blend during the extrusion were discussed in detail. It was found that the morphology of the dispersed particles and the interfacial adhesion between the dispersed phase and matrix were both influenced by the extrusion temperature. The dispersed phase had a spheroidal shape and a small size during the high temperature processing, and an irregular shape and a large size when it was processed at low temperature. The PC phase with a lower viscosity was easier to disperse and also to coalesce. Therefore, the deformation of the low-viscosity dispersed phase during the processing was more intense than that of the high-viscosity dispersed phase. By comparing the effects of the different screw configurations on the morphology development of the PC/PE blend, it was found that the melting and breaking up of the dispersed phase were mainly affected in the initial blending stages by the number of the kneading blocks. While a kneading block with a 90 degree staggering angle was used, the size of the dispersed particles decreased and the long fibers were shortened, the large particles were drawn by the additional kneading zone. Finally, all of these structures were completely changed to the short fibers. POLYM. ENG. SCI., 47:14,25, 2007. © 2006 Society of Plastics Engineers [source] Numerical analysis of polymer melt flow in the nipping regionPOLYMER ENGINEERING & SCIENCE, Issue 4 2002M. Takase In the extrusion coating process, it has never been revealed how a polymer melt flows near the nipping region and how the cooling process occurs. We created a numerical simulation program for the polymer melt flow near the nipping region using the finite element method. Numerical results showed the effects of many individual factors (e.g. line speed, melt thickness, extrusion temperature, shear-thinning property, etc.) on the cooling process and polymer melt flow near the nipping region. It was found that a polymer melt buildup that can be observed between two calender rolls in the sheet forming process also formed in the extrusion coating process, and that the amount of polymer melt buildup (bank) depended upon the coating condition. It was found that not only line speed and melt thickness contribute to the extrusion coating process significantly, but also the rheological property has an effect on the process. [source] Rheological behavior of highly filled ethylene propylene diene rubber compoundsPOLYMER ENGINEERING & SCIENCE, Issue 5 2000M. G. Markovic The rheological behavior of highly filled ethylene propylene diene rubber (EPDM) compounds was studied with respect to the effect of curative system, grafted rubber, shear rate, temperature and die swell using a Monsanto Processability Tester (MPT) to gain an understanding of the molecular parameters that control the surface finish. All systems show pseudoplastic behavior. At a particular shear rate, shear viscosity increases with blend ratio. The dependence of flow behavior on extrusion velocity indicates a surface effect. The extrudate die swell and maximum recoverable deformation are related by a linear relationship, which is independent of sulfur/accelerator ratio, extrusion temperature and shear rates and blend ratio. The principal normal stress difference increases nonlinearly with shear stress. Activation energy decreases with shear rate in most cases. The faster relaxing system produces extrudate of better surface quality. [source] High Strength Lead-Free Composite Solder Materials using Nano Al2O3 as ReinforcementADVANCED ENGINEERING MATERIALS, Issue 11 2005X. Zhong High strength light weight lead-free composite solder materials containing varying amount of nano-alumina particulates were synthesized by powder metallurgy process employing different extrusion temperatures. The presence of nano Al2O3 particulates not only enhanced strength and improved dimensional stability but also reduced the weight of the solder alloy matrix. Fairly uniform distribution of the nano-alumina particulates was observed in the composites. [source] | |||||||||||||