scholarly journals MATERIAL MOVEMENT WITHIN A SINGLE-SCREW EXTRUDER

2021 ◽  
pp. 421-429
Author(s):  
A.S. Dorokhov ◽  
M.G. Zagoruiko ◽  
A.M. Maradudin ◽  
I.A. Bashmakov

In present-day economic conditions, extrusion is one of the advanced feedstuffs and food production processes involving intensive manifold heat and force action. During extrusion, the main function is performed by a compression mechanism which includes a forcing screw unit built into the cylinder (cowling). The forcing mechanism performs the task of transferring material while concurrently compressing it up to a required pressure and increasing the material’s temperature due to compression and friction against the cowling's sides. In our view, the first technique is appropriate when a material which is moving within the compression area is in viscous-flow state. The second technique is optimal for theoretical description of areas of loading, transportation, and compression (melting) where the working pressure is maintained.

Author(s):  
Dr. G. Kaemof

A mixture of polycarbonate (PC) and styrene-acrylonitrile-copolymer (SAN) represents a very good example for the efficiency of electron microscopic investigations concerning the determination of optimum production procedures for high grade product properties.The following parameters have been varied:components of charge (PC : SAN 50 : 50, 60 : 40, 70 : 30), kind of compounding machine (single screw extruder, twin screw extruder, discontinuous kneader), mass-temperature (lowest and highest possible temperature).The transmission electron microscopic investigations (TEM) were carried out on ultra thin sections, the PC-phase of which was selectively etched by triethylamine.The phase transition (matrix to disperse phase) does not occur - as might be expected - at a PC to SAN ratio of 50 : 50, but at a ratio of 65 : 35. Our results show that the matrix is preferably formed by the components with the lower melting viscosity (in this special case SAN), even at concentrations of less than 50 %.


2012 ◽  
Vol 550-553 ◽  
pp. 1513-1521
Author(s):  
Sirirat Thothong ◽  
Klanarong Sriroth ◽  
Rattana Tantatherdtam ◽  
Amnat Jarerat

To improve the miscibility of native rice starch granules and poly(butylene adipate-co-terephthalate)(PBAT), rice starch was hydrolyzed by a mixture of α-amylase and amyloglucosidase. The obtained porous rice granular starch was then mechanically blended with PBAT by single screw extruder. Many pits and holes on the surface of starch granules were observed by scanning electron microscopy (SEM). The rough surface of the rice starch granules improved the compatibility of the polymers in the blends, which consequently increased the tensile strength and the elongation at break. In addition, SEM also revealed that the porous granules were homogeneously distributed in the polymer matrix with no appearance of gaps.


2018 ◽  
Vol 204 ◽  
pp. 00008
Author(s):  
Heru Suryanto ◽  
Alfian Widi Rahmawan ◽  
Solichin ◽  
Sahana Rizki Tata ◽  
Uun Yanuhar

The development of materials engineering has led to many significant discoveries one of which is biocomposite with its diverse applications. The addition of reinforcing materials in biopolymers improves the composite properties. This study aimed at investigating the effect of adding nanoclay on the tensile strength, morphology, functional group, and structure of extruded biocomposites with cassava starch matrix. This experimental research involved different concentrations of nanoclay i.e. 0%, 2.5%, 5%, 7.5%. The extrusion process was performed using a single screw extruder at 120°C. The samples were characterized by tensile testing, XRD, and SEM. The biocomposite reinforced with 5% nanoclay had the highest tensile strength of 10.8 MPa. The highest diffraction peak at 2θ of 19.4° appeared in the sample added with 5% nanoclay. The addition of excessive amounts of nanoclay can hinder the formation of exfoliated structures.


2013 ◽  
Vol 30 (1) ◽  
pp. 223-242
Author(s):  
M. A. Morcos ◽  
B. M. A. Amer ◽  
H. K. El-Manawaty ◽  
M. M. H. Zakzouk

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