Single Screw Extrusion Process Research Articles

Analysis on the Effect of Elevated Loading of Reclaimed Spent Bleach Earth on Physico-Mechanical Properties of PLA Polymer Composite in Single Screw Extrusion Process

Wood has found widespread use in various applications, however, this extensive usage has resulted in adverse environmental effects, such as contributing to global warming. To mitigate these impacts, there is potential in utilizing reclaimed spent bleach earth (SBE) as an alternative source for biocomposite materials. While polylactic (PLA) polymer is biodegradable, it exhibits limited mechanical properties. This study aims to explore the feasibility of incorporating SBE into polymer matrices. Different filler loading percentages for the PLA/SBE composite (0 wt.%, 10 wt.%, 20 wt.%, 30 wt.%, and 40 wt.%) and extruder temperatures (170°C and 180°C) were considered. The SBE powder underwent characterization using techniques including Particle Size Analysis (PSA), X-Ray Diffraction (XRD), and Field Emission with Energy Dispersive X-Ray (FESEM-EDX). Characterization data revealed that SBE particles ranged in size from 40.24 μm to 51.37 μm and exhibited a crystalline structure. Density of the SBE/PLA composite directly correlated with composition, whereas tensile strength and Young's modulus displayed an inverse relationship. Moreover, varying the temperature by 10°C did not result in significant property changes. The connection between properties and SBE filler loading was evident through alterations in density and Young's modulus values. Furthermore, the composite's behavior shifted from ductile to brittle. Examination of surface fractures through fractography established a link between composite properties, filler loading, and temperature. Images of all samples displayed well-dispersed structures without significant voids. In conclusion, ANOVA analysis indicated that filler loading significantly impacted strength properties. These findings serve as a valuable addition to the existing database, which is currently limited in its coverage of SBE/PLA polymer composites, particularly in applications like packaging.

Optimization of Single Screw Extrusion Processing Variables and Soy and Rice Flour Blend Formulations based on Physical Properties of Extrudates

Background: Extruded cereals and snacks are mainly carbohydrates. Most adults require more protein above RDA by restricting carbohydrates for many health benefits. A wide variety of soy protein-rich extrudates can be produced by blending with rice flour. However, optimum extrusion processing variables (i.e., screw speed, die temperature, and product formulations) are required for maximum retention of nutrients with desired product characteristics. Objective: The objective of this study was to optimize the extrusion operating conditions and soy flour and rice flour blend formulations for developing protein-rich cereal-like extrudates. Methods: Twenty formulations using CCRD with the combinations of soy flour content (43-77%), die temperature (123-157°C), and screw speed (250-350 rpm) were extruded using a single screw extruder. The physical properties (expansion ratio, density, porosity, hardness, crispness, color, and water solubility index) of extrudates were determined. The regression models and 3-dimensional response surface models were developed for each property of extrudates using RSM. Numerical and graphical optimizations were conducted based on the desirability to determine an optimum condition. Results: The regression models were able to predict the physical properties of extrudates with an accuracy of 75-90%, depending on their properties. The 3-dimensional response surface models indicated that the soy flour content, die temperature, and screw speed affected the physical properties of extrudates significantly (p < 0.05). Soy flour content (50-55%), die temperature (140-145°C), and screw speed (290-320 rpm) were very effective for the desired quality of soy flour and rice flour blend extrudates. Conclusion: The optimum condition is expected to be very useful for soy protein and rice flour blend extruded cereal-like product development commercially within the experimental range.

Optimisation of extrusion process parameters to make ABS-PC filament for 3D printing using Taguchi-GRA technique

ABSTRACT This paper attempts to optimise the single screw extrusion (SSE) process parameters for extruding Acrylonitrile-butadiene-styrene (ABS) and Polycarbonate (PC) blend filament, having improved tensile strength and melt flow rate. The melt flow and mechanical properties of ABS-PC blend filament are highly reliant on the SSE process parameters. Thus, optimising the process parameters to fabricate the blend filaments with high performance has become essential. Grey relational analysis has been integrated with the Taguchi method to optimise the SSE process parameters by evaluating the grey relational grades in terms of the performance index. Experimentation has been carried out according to Taguchi’s L9 orthogonal array (OA), which has been designed considering three SSE process parameters, i.e. screw rotation, blend composition and chamber temperature. The co-continuous structure and compatibility between the phases of the blend obtained at ABS:PC 50:50 by wt%. Micrographs and thermographs support the results. The tensile strength of the 3D printed ABS:PC 50:50 by wt.% composite specimen has improved by 38.02% as compared to virgin ABS.

The influence of calcium carbonate and its modifications on the extrusion process and selected functional properties of polypropylene cast films

The purpose of the article was to determine the influence of calcium carbonate and its modification (with stearic acid) on selected properties of composite polypropylene films and their processing. Polypropylene composites containing, respectively, 5, 10, 20 and 30 wt% filler, were made in twin-screw extrusion process with cold granulation. Films, on the other hand, were produced in single-screw extrusion process (an extruder with a screw with diameter d = 20 mm and ratio l/d = 24) using a flat head (so-called cast films) and a chill roll type cooling and pull-back device. The pull-back rotational speed was selected so as to obtain films of a thickness of approx. 120 µm, irrespectively of the composite being processed. The assessment of the effect of the addition of applied fillers on the magnitude of the melt volume-flow rate (MVR) of polypropylene and the processing characteristic of extrusion process was made (the flow resistance and the variations in volumetric flow rate were determined). It was demonstrated how variations in the processability of polymeric material determined the correction of extrusion process setup parameters (pull-back system speed). The processability of composite films under extensional flow conditions was also determined by evaluating the extensional viscosity (ηE) of the composites. The strength values of composite films were determined under static tension conditions and in puncture tests. The effect of the content and modification of CaCO3 on the film haze and gloss was also assessed. The investigation carried out has demonstrated a direct effect of the addition of calcium carbonate and its modification on the processability and selected functional properties of composite films. The study has also proved that stearic acid is an effective modifier of processing properties, not only in shear flow conditions, but also under extensional flow conditions – smaller ηE values are exhibited by films containing modified calcium carbonate.

Experimental and Numerical Analysis of Single Screw Extrusion Process for Thermoplastic PBX Based on PVT Properties

Much of surplus ammunition stockpile inevitably requires demilitarized processing technology in the explosives industry. For the safe waste treatment and recycle, the thermoplastic polymer bonded explosive (PBX) can effectively reduce the military cost and non-conforming products. In addition, the thermoplastic PBX has excellent application prospect as the future explosive due to the good mechanical properties and insensitivity. However, for high solid content, most of thermoplastic PBXs still maintain a considerable viscosity even in high-temperature melting state, rendering traditional casting process unsuitable. In this study, a measuring method was adopted to accurately obtain the correlation of Pressure-Volume-Temperature (PVT) for the simulative materials of thermoplastic PBX at first. The equations of state for PVT and viscosity model were then created, which are of great significance in single screw extrusion. An experiment system of single screw extrusion was designed to implement the molding process considering the poor liquidity problem of the thermoplastic materials. Excellent molding stability (ρ<0.5 % variation) was achieved for the extrusion system. Moreover, a numerical investigation was also performed. Good agreements were yielded by comparing the simulation data and experimental results. The effects of operational parameters, i. e., the entrance pressure, barrel temperature and rotation speed on molding process of the thermoplastic materials were investigated in detail. The wall shear stress decreases with the feed inlet well sealed whereas the maximum temperature rise increases a little due to limited thermal diffusion. Either increasing temperature or decreasing rotation speed is beneficial to overall process safety. However, production cycle and attainable molding density also need to be considered at the same time. Furthermore, the process parameters should be optimized on the basis of the PVT and viscosity properties of material in practice. The investigations above can be a better guidance for the development and implementation of thermoplastic PBXs molding process.

Conversion of Industrial Food Wastes Cranberry Pomace into Foods Blending with Rice Flour Using Single-screw Extrusion Process

The main objective of this study was to convert the cranberry pomace into value-added extruded cereals/snacks blending with rice flour using a single screw extruder based on the physicochemical properties of extrudates because utilization of the byproduct cranberry pomace would be necessary for the growth of cranberry juice processing industries and the extruded snacks/cereals with higher fiber and antioxidant and less carbohydrate would be required to fulfill the consumers’ demand. The six different formulations by blending 0, 5, 10, 15, 20 and 25% cranberry pomace with 100, 95, 90, 85, 80 and 75% of rice flour, respectively, were extruded using a single screw extruder. The temperature (150℃), screw speed (270 rpm), feed rate (20 Kg/hr) and feed moisture content (35%) were constant during extrusion. The physicochemical properties of the extrudates were characterized to determine the desirable formulations. The results indicated that radial expansion ratio (1.11-1.67), the solid density (0.71-0.76 g/mL), piece density (0.20-0.63 g/mL), porosity (14.49-72.38%), hardness (23-157.73 N), crispness (4.17-13.5), moisture content (3.22-4.39%), water activity (0.14-0.36) and the water solubility (7.07-30.80%) of rice flour and cranberry pomace blend extrudates were varied depending on the combinations of the rice flour and cranberry pomace. The results revealed that up to 20% cranberry pomace could be added with 75-80% rice flour to develop high fiber and antioxidant with less carbohydrate cereal/snack products. The utilization of cranberry pomace combining with rice flour through extrusion process can provide a unique opportunity to generate healthier snacks and cereals that have higher fiber and antioxidant and low carbohydrate.

Influence of the parameters of the extrusion process on the properties of PLA composites with the addition of graphite

The main purpose of the work is to determine the influence of the screw diameter on the parameters of the single screw extrusion process, such as power consumption, torque, throughput, the actual temperature of the melt on the extruder die, as well as phase s with the use of a laboratory single-screw extruder.. The research was carried out with the use of various plasticizing systems. Two types of graphite: pre-expanded and normal grade with different grain sizes were used in the research. Flammability tests of the obtained composites were carried out using cone calorimeter.

Can filaments, pellets and powder be used as feedstock to produce highly drug-loaded ethylene-vinyl acetate 3D printed tablets using extrusion-based additive manufacturing?

Personalized medicine, produced through 3D printing, is a promising approach for delivering the required drug dose based on the patient's profile. The primary purpose of this study was to investigate the potential of two different extrusion-based additive manufacturing techniques – fused filament fabrication (FFF) and screw-based 3D printing, also known as direct extrusion additive manufacturing (DEAM). Different ethylene-vinyl acetate (EVA) copolymers (9 %VA, 12 %VA, 16 %VA, 18 %VA, 25 %VA, 28 %VA, and 40 %VA) were selected and loaded with 50% (w/w) metoprolol tartrate (MPT). Hot-melt extrusion was performed to produce the drug-loaded filaments. These filaments were used for FFF in which the mechanical and rheological properties were rate-limiting steps. The drug-loaded filament based on the 18 %VA polymer was the only printable formulation due to its appropriate mechanical and rheological properties. As for the highest VA content (40 %VA), the feeding pinch rolls cause buckling of the filaments due to insufficient stiffness, while other filaments were successfully feedable towards the extrusion nozzle. However, poor flowability out of the extrusion nozzle due to the rheological limitation excluded these formulations from the initial printing trials. Filaments were also pelletized and used for pellets-DEAM. This method showed freedom in formulation selection because the screw rotation drives the material flow with less dependence on their mechanical properties. All drug-loaded pellets were successfully printed via DEAM, as sufficient pressure was built up towards the nozzle due to single screw extrusion processing method. In contrast, filaments were used as a piston to build up the pressure required for extrusion in filament-based printing, which highly depends on the filament's mechanical properties. Moreover, printing trials using a physical mixture in powder form were also investigated and showed promising results. In vitro drug release showed similar release patterns for MPT-loaded 3D printed tablets regardless of the printing technique. Additionally, pellets-DEAM enabled the production of tablets with the highest VA content, which failed in FFF 3D printing but showed an interesting delayed release profile.

Experimental study of energy performance of grooved feed and grooved plasticating single screw extrusion processes in terms of SEC, theoretical maximum energy efficiency and relative energy efficiency

Experimental results of SEC, energy efficiency, backpressure and melt temperature in GFE and GPE as functions of PUT, rotational screw speed and die restriction are analyzed. For GFE, five screws are analyzed: two conventional, two barrier and one with a double-flighted feed zone. The polymer, motor drive, control system, die, screw diameter and length and temperature profile are the same. The differences in the results can be attributed to the PUT. Results show that the differences in the geometry of the GFE screws affect the extruder operational windows but do not significantly affect the SEC as a function of throughput. GPE shows higher productivity with a lower pressure requirement, SEC and melt temperature compared to GFE configurations. When the SEC of heaters and motor drive is compared between GPE and GFE technology, the behavior of the heater bands is similar but the motor drive energy is more efficiently used in GPE. A novel approach to the ηmax and ηr in polymer extrusion is proposed, obtaining between 54.2% and 84.2% for maximum efficiency and 61.3%–86.2% for relative efficiency, depending on the PUT and the die restriction.

Single Screw Extrusion Processing of Enriched Snacks at Various Levels of Brewers Spent Yeast and Soybean Meal

In the current years, the significance of a healthful diet, dietary composition, and food quality has been gradually heightened because of more and more conscious of the health-promoting constituent of foods by consumers. Thus, the study examined the production of enriched ready-to-eat snacks through extrusion from composite non-wheat based cereal flour of yellow maize. All raw materials were obtained from local markets across Ondo and Osun states markets after which they were sorted, cleaned, dried and milled into a powder. Samples were formulated in the following ratios (yellow maize/ defatted soy flour/ brewers’ spent yeasts): 35:30:10 (YMDS), 35:25:15 (YMDD), 35:20:20 (YMDB), 35:10:30 (YMDF) and they were compared with a wheat-based market snack which was the control. The functional, proximate, minerals, antioxidant and sensory properties of the snacks were analysed using standard methods. Results on dry basis established that an increase in brewers’ spent yeast substitution in the formulation significantly (p≤ 0.05) increased protein (23.07 - 26.84%) and carbohydrate (43.26 – 74.73 %) contents. While crude fibre (5.50-6.69%), ash (8.71-8.86%) and fat contents (13.37-17.85%) significantly increased with defatted soy substitution (p ≤ 0.05). However, total phenol, ascorbic acid, and total flavonoid contents also increased significantly with defatted soy flour substitution. Finally, no significant difference (p≤ 0.05) among all the sample appearance, taste, aroma, and texture (crispness) and sample (YDMF) favourably compared with a market snack in the sensorial properties evaluated and was generally more accepted.

Impact of the Pretreatment of Grains on the Interparticle Porosity of Feed Material and the Torque Supplied During the Extrusion of Brown Rice

The objective of this work was to evaluate the effects of drying, grinder type, and moistening conditions on the interparticle porosity of feed material and the torque supplied to the screw during the single-screw extrusion processing of brown rice. The grains were dried at 60 °C up to moisture contents of 9 and 6% and then milled using two grinder types (disc and roller). The milled products were moistened at levels to produce extruded snacks (11 and 14%). Irrespective of drying the grains, lower particle diameters in the fine and coarse fractions, and narrower distributions were obtained by grinding brown rice in a roller mill than in a disc mill. The disc mill products presented lower interparticle porosity and generated higher torque values than the roller mill products. A reduction in grain moisture from 9 to 6% only decreased the interparticle porosity of disc mill products and increased the torque. An increase in feed moisture from 11 to 14% only increased the interparticle porosity of roller mill products and decreased the torque regardless of grain moisture. This work contributed to understanding the impact of the morphology of the particles in the torque variability during the extrusion processing of brown rice. Few published works correlate physical properties of the feed material with extrusion dependent variables. In the present study, feed materials with high interparticle porosity were produced with roller mill and when extruded they generated low variabilities in the torque.

Global Modeling of Single Screw Extrusion with Slip Effects

Abstract An extensive study is presented on the polymer melt flow with slip effects in a single screw extrusion process. Fully three-dimensional non-Newtonian FEM computations are performed to design the screw pumping characteristics and the die characteristics which may be implemented into the composite model of the process. ANSYS Polyflow software is applied to model the melt flow in the extruder. An analysis is performed for the flow of polymers with slip effects both in the screw (on the screw and barrel surfaces) and in the die. Screw pumping characteristics and die characteristics are calculated and modeled for various power law indices, and various slipping parameters. The effect of slipping on extruder operation is discussed.

A finite-element technique for flows in the single screw extruder using a partial periodic unit

It is of great importance to understand and predict screw characteristics (SC) during the single screw extrusion process for the extruder design and the operation optimization. In order to simulate SC effectively, we introduce the concept of a partial rotational fraction for a partial periodic unit of helical geometry in the metering section of the single screw extruder. In this work, the partial rotational fraction has been implemented with the finite element. We report that simple and accurate computation can be achieved at low computational cost in obtaining the three-dimensional flow field and three-dimensional screw characteristics in terms of material properties with the proposed partial period unit concept in the single screw extruder.

Preparation and application of macromolecules with a fluorescence effect in polymer processing

ABSTRACTIn this study, 9-anthracenemethyl methacrylate (AMMA) and styrene (St) as monomers and benzoyl peroxide as an initiator were used to synthesize P(St-co-AMMA), a macromolecule tracer with a fluorescence effect, via free radical copolymerization. A fluorescent online detection device was built on the basis of the principle of fluorescence online detection by using the single-screw extrusion platform of a torque rheometer to explore the effect of the amount of macromolecular tracer and screw speed on the residence time distribution of polystyrene in single-screw extrusion. Fourier transform infrared spectroscopy, 1H-NMR, thermal stability, fluorescence properties, and rheological properties show that the resulting product P(St-co-AMMA) has a degree of thermal stability, fluorescence, and rheological properties similar to polystyrene, so this product can be used to characterize the residence time distribution during single-screw extrusion. The amount of macromolecular tracer P(St-co-AMMA) does not affect the residence time distribution of polystyrene during single-screw extrusion processing, meanwhile, the minimum residence time decreases and the residence time distribution becomes narrow as the screw speed increases, that is, the axial mixing capacity of the single-screw extruder decreases as the screw speed increases.

Dimensionless analysis of three-dimensional residence time distribution in single-screw extrusion processes

It is of great importance to understand and predict Residence Time Distribution (RTD) during a singlescrew extrusion process for extruder design and operation optimization purposes. RTD depends on the extruder geometry, operating conditions, and material properties of non-Newtonian fluids. This paper presents the proper dimensionless parameters and RTD for the three-dimensional circulatory flow. These dimensionless parameters were expressed in terms of physical and geometrical parameters such as flow rate, pressure gradient along down channel direction, aspect ratio, helix angle, and power-law index. RTD computations and analysis were based on the finite element method. This dimensionless parameter study is found to be very useful for extruder designers to understand and to predict the RTD systematically.

3D printing of shape memory polymer (SMP)/carbon black (CB) nanocomposites with electro-responsive toughness enhancement

In this work, a simple approach to 3D printing of carbon black based shape memory polymer nanocomposites (SMP/CB) with toughness improving capabilities during programing stage using electrical stimulus is reported. Conductive SMP/CB nanocomposites, consisting of commercial SMP filled with conductive CB nanoparticles, were fabricated using solvent casting and single screw extrusion processes. Subsequently, material extrusion (ME) technique was used to 3D print dog bones type IV specimens for tensile test and electrical stimulus. It was found that SMP/CB electrical conductivity can be tuned by the filler fraction. In addition, electrical current passing through SMP/CB nanocomposites causes temperature increments and changes on material strength condition. Temperature profiles at various electrical current levels are reported. Moreover, Young’s modulus and toughness of the 3D printed specimens subjected and not subjected to electrical current are presented. It was observed that conductive SMP/CB specimens responded to electrical current stimulus by increasing their toughness four times higher than with no current applied during tensile test. This paper is a reference for rheological and conductive properties of SMP/CB nanocomposites fabricated by ME 3D printing process.

Uogolniony model uplastyczniania tworzyw polimerowych w procesie wytlaczania

A procedure of general modeling of polymer melting in extrusion process has been presented. The procedure is independent on the type of extrusion, and does not require any knowledge of melting mechanism. The procedure involves modeling the two-phase flow (fluid/solid) as a single-phase flow in which the material, depending on the flow conditions, is solid or fluid. Cross-WLF rheological model has been used, which defines the solid polymer as a high viscosity fluid, while the polymer melt as a low viscosity fluid. The problem has been solved for single screw extrusion process as a three-dimensional, non-isothermal, non-Newtonian flow using CFD (Computational Fluid Dynamics) software. Melting progress is defined by the temperature distribution which determines the regions of solid and fluid.

Optimization of single screw extrusion process for producing fish feeds based on vegetable meals and evaluation of nutritional effects using a juvenile Piaractus mesopotamicus model

Optimization of extrusion process for producing extruded feeds based on vegetable meals using a single screw extruder was study. Also growth performance of extruded feed obtained in optimal conditions using a juvenile P mesopotamicus model was evaluated. In order to study the simultaneous effect of blend moisture (M) and extrusion temperature (T) on expansion (E), bulk density (BD), water absorption index (WAI), water solubility index (WSI), and floatability (F) a central composite design (32) was used. The levels of each variable were: T: 160–180–200°C and M: 14–16–18g/100g. A multiple response optimization of physical properties of experimental extruded feed (E, F, BD and WSI) was performed using the Derringer’s desirability function. The global desirability function value was 0.8805, and the obtained optimal conditions were 181.5°C and 15.8g/100g of moisture content. Experimental extruded feed (EF) obtained at such conditions presented the following physical properties: E: 2.23±0.03, F: 99.0±1.0%, BD: 270.9±13.8g/L, and WSI: 12.9±1.5g/100g. Crude protein content of EF was higher than that of control feed (CF). However, no significant difference for crude lipid (∼37.9g/kg) and total starch content was found. Gelatinized starch for EF (430.5±7.0g/kg) was higher than that obtained for CF (378.9±6.7g/kg), corresponding to 97.0±2.1 and 88.1±2.2% of degree of gelatinization, respectively. Chemical score of CF was 93.3%, lysine being the limiting amino acid. However, in the case of EF no limiting amino acid was found. Both diets presented a predominance of unsaturated fatty acids of C18 series (C18:1 and C18:2 (n–6)). EF showed higher content of oleic, linolenic, cis-11-eicosenoic and di-homo-γ-linolenic acid than CF. Nevertheless, only for CF, eicosapentaenoic acid, docosapentaenoic, and docosahexaenoic acid were detected. Significant differences in final fish body weight, weight gain, specific growth rate, and condition factor were not detected between dietary treatments after 120days of feeding trial. Extrusion using a single screw extruder in optimal process conditions could be used to obtain fish feed based in vegetable meals and good physical properties with proper growth performance on juvenile P. mesopotamicus.

Preparation of High Modulus Poly(Ethylene Terephthalate): Influence of Molecular Weight, Extrusion, and Drawing Parameters

Poly(ethylene terephthalate) (PET) which is one of the most commercially important polymers, has for many years been an interesting candidate for the production of high performance fibres and tapes. In current study, we focus on investigating the effects of the various processing variables on the mechanical properties of PET produced by a distinctive process of melt spinning and uniaxial two-stage solid-state drawing (SSD). These processing variables include screw rotation speed during extrusion, fibre take-up speed, molecular weight, draw-ratio, and drawing temperature. As-spun PET production using a single-screw extrusion process was first optimized to induce an optimal polymer microstructure for subsequent drawing processes. It was found that less crystallization which occurred during this process would lead to better drawability, higher draw-ratio, and mechanical properties in the subsequent SSD process. Then the effect of drawing temperature (DT) in uniaxial two-stage SSD process was studied to understand how DT (&lt;Tg or close to Tg or close to Trec) would affect the crystallization, draw-ratio, and final mechanical properties of PET. The designed process in current work is simulated to an industrial production process for PET fibres; therefore, results and analysis in this paper have significant importance for industrial production.

Modelling the Peak Elongation of Nylon6 and Fe Powder Based Composite Wire for FDM Feedstock Filament

In the present work, to increase the application domain of fused deposition modelling (FDM) process, Nylon6–Fe powder based composite wire has been prepared as feed stock filament. Further for smooth functioning of feed stock filament without any change in the hardware and software of the commercial FDM setup, the mechanical properties of the newly prepared composite wire must be comparable/at par to the existing material i.e. ABS, P-430. So, keeping this in consideration; an effort has been made to model the peak elongation of in house developed feedstock filament comprising of Nylon6 and Fe powder (prepared on single screw extrusion process) for commercial FDM setup. The input parameters of single screw extruder (namely: barrel temperature, temperature of the die, speed of the screw, speed of the winding machine) and rheological property of material (melt flow index) has been modelled with peak elongation as the output by using response surface methodology. For validation of model the result of peak elongation obtained from the model equation the comparison was made with the results of actual experimentation which shows the variation of ±1 % only.