scholarly journals Effect of the Intensive Plasticizing Zone Design on the Effectiveness of Corotating Twin-Screw Extrusion

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Emil Sasimowski ◽  
Łukasz Majewski

The aim of this study was to investigate the effect of a new intensive plasticizing and mixing screw zone design on the effectiveness of the corotating twin-screw extrusion process for talc-filled polypropylene. The study determined the effect of the angle between the trilobe kneading elements forming the intensive plasticizing and mixing zone of the screws, the screw rotational speed, and the polypropylene/talc filling ratio on the characteristics of the extrusion process in a corotating twin-screw extruder EHP-2x20. The paper describes the experimental design and obtained results as well as the developed empirical models for selected variables of the extrusion process.

Polymers ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1460 ◽  
Author(s):  
Sasimowski ◽  
Majewski ◽  
Grochowicz

The aim of the study was to determine the effect of the application of processing screws with a modified test segment in a corotating twin-screw extruder on selected properties of talc-filled polypropylene extrudate. The test segment was built of trilobe kneading elements and its design modifications refered to changing the distance between the kneading elements and the angle of positions of kneading elements that are relative to each other. The performed tests included the production of extrudate with various degrees of talc-filling using five design solutions of the test segment and then measurements of selected properties, such as tensile strength, elongation at maximum tensile stress, and melt flow rate. Structural studies using scanning electron microscope (SEM) and differential scanning calorimetry (DSC) were also carried out. The study includes not only the description of experimental results but also the determination of empirical models describing the dependence of the properties of the obtained extrudate on the conditions of the extrusion process and the design features of the test segment.


2013 ◽  
Vol 80 (3) ◽  
Author(s):  
Thelma G. Manning ◽  
Joseph Leone ◽  
Martijn Zebregs ◽  
Dinesh R. Ramlal ◽  
Chris A. van Driel

In order to eliminate residual solvents in ammunition and to reduce the emissions of volatile organic compounds to the atmosphere, the U.S. Army ARDEC has teamed with TNO in developing a new process for the production of solventless propellant for tank ammunition. To reduce the costs of solventless propellants production, shear roll mill and continuous extrusion processing was investigated. As described in this paper JA-2 a double base propellant cannot be processed without solvent by the extrusion process. An alternative JA-2 equivalent propellant was defined. The aim of this work is to demonstrate the manufacturing of this propellant by solventless continuous twin screw extrusion processing while maintaining gun performance characteristics of conventional JA-2 propellant. This is elucidated by explicitly researching the relationship between interior ballistic properties of the gun propellant and utilizing a continuous manufacturing process. Processing conditions were established, and the propellant was manufactured accordingly. The extruded propellant has the desired properties, which resulted in a comparable gun performance as the conventional JA-2 propellant.


Extrusion ◽  
2014 ◽  
pp. 111-120 ◽  
Author(s):  
John R. Wagner ◽  
Eldridge M. Mount ◽  
Harold F. Giles

2012 ◽  
Vol 204-208 ◽  
pp. 4088-4092
Author(s):  
Ming Ming Zhang ◽  
Xiao Huan Liu ◽  
Chun Peng Wang ◽  
Li Wei Jin

The blend composite materials of bio-ethanol byproduct-Poly(lactic acid) (PLA) were produced by a twin-screw extrusion process. Effects of bio-ethanol byproduct (BEB) contents and different compatibilizers on properties of composite materials were investigated. The research showed that with the increase of contents of bio-ethanol byproduct, the mechanical properties decreased. The mechanical properties of composites were improved by adding the compatibilizers, especially the polypropylene grafted maleic anhydride (PP-MAH). When the PP-MAH content was 2.5%, the mechanical properties of the composite materials were superior to others.


2006 ◽  
Vol 45 ◽  
pp. 436-441 ◽  
Author(s):  
P.A. McGuire ◽  
S. Blackburn ◽  
E.M. Holt

A mathematical model has been derived to describe the pressure drop along the conveying and reverse sections of a partly full, fully intermeshing co-rotating twin-screw extruder. The model extends previous work on single screw extrusion, whereby the Benbow-Bridgwater model of paste rheology is combined with a force balance on a plug of paste. Experiments to verify the model have been carried out using a laboratory scale twin-screw extruder fitted with a hydraulic feeder and a modified barrel section allowing the collection of pressure data at numerous points along the extruder. Initial results suggested that the model was able to correctly predict the trends observed but underestimated the absolute values of the pressure. This was attributed to a change in the rheology of the paste due to viscous heating effects. Further experimental work was carried out to determine the relationship between the rheological parameters and temperature; this allowed a temperature correction to be made to the initial data after which the agreement with the predictions was greatly improved.


1988 ◽  
Author(s):  
Dilhan M. Kalyon ◽  
Alexandros D. Gotsis ◽  
Costas G. Gogos ◽  
Christos Tsenoglou

2019 ◽  
Vol 8 (1) ◽  
Author(s):  
Nahemiah Danbaba ◽  
Iro Nkama ◽  
Mamudu Halidu Badau

In this study, seventeen (17) composite blends of broken rice fractions and full-fat soybean, formulated using response surface methodology and central composite design within a range of barrel temperatures (100-140 °C), initial feed moisture content (15-25%) and soybean composition (8-24%), were extruded with a twin-screw extruder and the expansion and color indices were optimized. The results indicated a significant (p<0.05) effect of extrusion conditions on the responses. Fitted predictive models had coefficients of 88.9%, 95.7%, 97.3%, 95.4% and 95.2%, respectively, for expansion index, bulk density, lightness, redness and yellowness. The p-value and lack-of-fit tests of the models could well explain the observed variability and therefore could be used to establish production setting for the twin-screw extruder. The optimum extrusion conditions were found to be 130 °C (barrel temperature), 20% (feed moisture level) and 23% feed soybean composition and optimum responses in terms of bulk density, expansion index, lightness, redness and yellowness chroma indices were 0.21 g cm-3, 128.9%, 17.1, 3.13 and 24.5 respectively. This indicates that optimum conditions can be established in twin-screw extrusion cooking of broken rice fractions and full-fat soybean composite blends that can result in product of low bulk and maximum expansion with a satisfactory light yellow product color that can be used to produce products that valorize broken rice and reduce qualitative postharvest loss.


2011 ◽  
Vol 393-395 ◽  
pp. 1203-1211
Author(s):  
Bing Du ◽  
Yan Li Jiao ◽  
Zhi Qiang Huang ◽  
Lian Kai Mao ◽  
Yuan Yuan Fan ◽  
...  

In order to increase the extraction rate of flavonoids from mungbean skin, twin-screw extrusion process was used as a pretreatment method. After optimizing conditions of twin-screw extrusion process, effects on ethanol extracting flavonoids were studied. Results revealed that the best extrusion conditions were: screw speed at 268r/min, extrusion temperature at 115~120°C, feed moisture at 17% and feeding rate at 726g/min. Under these conditions, the optimum condition for ethanol extraction of flavonoids was: using 38% ethanol solution at a material-liquid ratio of 1:20 at 77.5 °C with 2.5 h. The average extraction rate of flavonoids from mungbean skin was 3.14%, comparing to rate of un-extruded material 2.07%, extraction rate raised by 51.5%. This pretreatment can destroy the density structure of mungbean skin which has great effect on the increase of extraction rate of flavonoids.


Sign in / Sign up

Export Citation Format

Share Document