scholarly journals Compounding of Short Fiber Reinforced Phenolic Resin by Using Specific Mechanical Energy Input as a Process Control Parameter

2021 ◽  
Vol 5 (5) ◽  
pp. 127
Author(s):  
Robert Maertens ◽  
Wilfried V. Liebig ◽  
Peter Elsner ◽  
Kay A. Weidenmann

For a newly developed thermoset injection molding process, glass fiber-reinforced phenolic molding compounds with fiber contents between 0 wt% and 60 wt% were compounded. To achieve a comparable remaining heat of the reaction in all compound formulations, the specific mechanical energy input (SME) during the twin-screw extruder compounding process was used as a control parameter. By adjusting the extruder screw speed and the material throughput, a constant SME into the resin was targeted. Validation measurements using differential scanning calorimetry showed that the remaining heat of the reaction was higher for the molding compounds with low glass fiber contents. It was concluded that the SME was not the only influencing factor on the resin crosslinking progress during the compounding. The material temperature and the residence time changed with the screw speed and throughput, and most likely influenced the curing. However, the SME was one of the major influence factors, and can serve as an at-line control parameter for reactive compounding processes. The mechanical characterization of the test specimens revealed a linear improvement in tensile strength up to a fiber content of 40–50 wt%. The unnotched Charpy impact strength at a 0° orientation reached a plateau at fiber fractions of approximately 45 wt%.

Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 153
Author(s):  
Katarzyna Lisiecka ◽  
Agnieszka Wójtowicz

The aim of the study was to examine the effect of fresh vegetable addition on processing efficiency, and to ascertain the energy and water consumption during production of potato-based snack pellets. The extrusion-cooking process with a modified single screw extruder was applied at variable screw speeds and amounts of vegetable additives. A mixture of potato flakes, potato grits and starch was used as a basic recipe. The potato composition was supplemented with fresh pulp of onion, leek, kale and carrot in amounts of 2.5–30.0% as replacement of a related amount of potato starch. The water consumption, as well as processing indicators: the production efficiency, the specific mechanical energy (SME), and the total SME requirements during snack pellets processing at the laboratory scale were evaluated. As a result of this work, we found that the amount of applied vegetable additives had little impact on both processing efficiency and SME depending on the screw speeds applied. Moreover, we saw increased processing efficiency with increased screw speed during extrusion. Of particular note, maximum value of processing efficiency was observed if fresh onion was used as an additive at the highest speed screw. Furthermore, the lowest specific mechanical energy consumption was noted for extrudates supplemented with fresh onion addition processed at the lowest screw speed. The most important limiting of water consumption during processing without negative effects on processing efficiency and quality of the final snack pellets was observed if 20% to 30% of fresh vegetables were used in the recipe. We believe that application of fresh vegetable pulp limited the energy requirements by mitigating the drying process of additives.


2014 ◽  
Vol 10 (3) ◽  
pp. 503-510 ◽  
Author(s):  
Gurkirat Kaur ◽  
Savita Sharma ◽  
Baljit Singh

Abstract Rice flour, wheat flour and flour in combination (rice:wheat::50:50) were used to prepare modified flour using co-rotating twin screw extruder. The effects of barrel temperature, feed moisture and screw speed on product responses (specific mechanical energy[SME], expansion ratio and bulk density) were studied using response surface methodology. Extrusion variables were barrel temperature (125, 150 and 175°C), moisture content (14, 16 and 18%) and screw speed (300, 400 and 500 rpm). Expansion ratio was directly affected by barrel temperature, whereas increase in temperature decreased SME and bulk density. Feed moisture had positive effect on bulk density only, i.e. it increased with increase in moisture. Increase in screw speed was directly related to SME and expansion ratio. The higher R2 values showed that the model developed for the response variables appeared adequate for predictive purposes.


2003 ◽  
Vol 9 (2) ◽  
pp. 101-114 ◽  
Author(s):  
H. Doğan ◽  
M. V. Karwe

Response surface methodology (RSM) was used to analyse the effect of temperature, screw speed, and feed moisture content on physicochemical properties of quinoa extrudates. A three-level, three-variable, Box-Behnken design of experiments was used. The experiments were run at 16-24% feed moisture content, 130-170°C temperature, and 250-500 rpm screw speed with a fixed feed rate of 300 g/min. Second order polynomials were used to model the extruder response and extrudate properties as a function of process variables. Responses were most affected by changes in feed moisture content and temperature, and to a lesser extent by screw speed. Calculated specific mechanical energy (SME) values ranged between 170-402 kJ/kg which were lower than those observed for other cereals, most likely due to high (7.2%) fat content of quinoa. High levels of feed moisture alone, and in combination with high temperature, resulted in poor expansion. The best product, characterised by maximum expansion, minimum density, high degree of gelatinization and low water solubility index, was obtained at 16% feed moisture content, 130°C die temperature, and 375 rpm screw speed, which corresponds to high SME input. It was demonstrated that the pseudo-cereal quinoa can be used to make novel, healthy, extruded, snack-type food products.


2016 ◽  
Vol 20 (2) ◽  
pp. 125-131 ◽  
Author(s):  
Magdalena Kręcisz

AbstractThe objective of the paper was to determine the impact of the rotational screw speed and the level of moisture of raw material on the efficiency and energy consumption of the extrusion-cooking process. Measurement of the extrusion-cooking process efficiency (Q) was carried out through determination of the extrudates mass and energy consumption was determined with the use of a specific mechanical energy (SME). Based on the research results it was found out that the factor which significantly decides on the measured values was a rotational screw speed. Along with the increase of this parameter the energy consumption and extrusion-cooking process efficiency increased during processing of corn grits. Extrusion-cooking process efficiency depended also on the level of moisture of raw material. At lower moisture of raw material the efficiency decreased along with the increase of the screw speed and above 18% of the moisture level it increased. Reverse relation was reported during testing the energy consumption of the extrusion-cooking process.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
The-Thiri Maung ◽  
Bon-Yeob Gu ◽  
Gi-Hyung Ryu

AbstractTo investigate the effect of process parameters during high-moisture extrusion on system parameter (specific mechanical energy, SME) and product physical properties, blend of soy protein isolate, wheat gluten, and corn starch (50:40:10 w/w) was extruded using co-rotating twin screw extruder equipped with cooling die at 55 and 65% feed moisture, 150 and 170 °C barrel temperature, 150 and 200 rpm screw speed. The hardness and chewiness of products increased as all the extrusion process parameters became low. Among the tested range of process parameters in this study, a combination of high moisture (65%), high barrel temperature (170 °C), and low screw speed (150 rpm) generated the low SME input (less energy consumption) with high texturization degree of meat analogs. Layer and fibrous structure formation of the samples were influenced by variations in process parameters, primarily feed moisture and barrel temperature.


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