Design of Tightly Intermeshing Co-Rotating Twin Screw Extruders

Potente, H.; Ansahl, J.; Klarholz, B.

doi:10.3139/217.940011

Cited by 61 publications

(49 citation statements)

References 5 publications

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“…Figure 1 demonstrates that the level of dispersive mixing achieved can be increased by reducing the extruder output; in agreement with [16,18,22]. At the same screw speed (peak shear stress) a reduction in output reduces the average DOF within the screw channel increasing the mean shear stress experienced by the polymer/additive [12] thus increasing dispersion via fast rupture mechanism. A reduction in output also increases the residence time, thus increasing the contribution of the slower erosion mechanism [13].…”

Section: Impact Of Extruder Outputsupporting

confidence: 66%

“…Extruder screw speed directly affects the shear rate and the shear stress experienced by the material thus influencing dispersion. While, the throughput governs the specific mechanical energy (SME) input, both of these control the degree of fill (DOF) changing average shear rate and stress experienced by the polymer [12]. It's vital to understand the degree of control these parameters offer over the process/product.…”

Section: Introductionmentioning

confidence: 99%

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Investigating the impact of operating conditions on the extent of additive mixing during thermoplastic polymer extrusion

Stratiychuk-Dear

Looney²,

Oliver³

et al. 2017

AIP Conference Proceedings

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Abstract. Adequate dispersion of the additive in polymer composites is vital to their performance. Dispersion occurs via rupture, erosion and collision induced mechanisms. Organophosphorus salt/PET nanocomposites were manufactured on a co-rotating fully intermeshing pilot scale twin screw extruder to determine the impact of operating conditions on the mixing achieved in order to understand the level of control available over the process. The effect on key dispersion mechanisms is discussed. Dispersion was found to increase with decreasing throughput, increasing screw speed and increasing molecular weight of the polymer. Linear relationships between calculated parameters including specific mechanical energy, degree of fill and specific throughput were also observed. A need for a compromise between achieving the desired level of mixing and maintaining the molecular weight of the polymer is established.

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Section: Impact Of Extruder Outputsupporting

confidence: 66%

Section: Introductionmentioning

confidence: 99%

Investigating the impact of operating conditions on the extent of additive mixing during thermoplastic polymer extrusion

Stratiychuk-Dear

Looney²,

Oliver³

et al. 2017

AIP Conference Proceedings

View full text Add to dashboard Cite

show abstract

“…15,16 Global (plasticating) models, taking into account the whole history of the extruded material from the hopper to the die exit, have also been published. [17][18][19][20] In the present study of such a global model, the software Ludovic was used to predict the flow conditions along the extruder. The direct comparison between measured and computed values is important for assessing the theoretical model and may suggest relevant modifications that may improve the accuracy of its predictions.…”

Section: Introductionmentioning

confidence: 99%

Experimental and theoretical study of twin-screw extrusion of polypropylene

Carneiro

Covas

Vergnes

2000

J. Appl. Polym. Sci.

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The flow of a polypropylene in a self‐wiping corotating twin‐screw extruder was characterized by measuring the pressure, temperature, and residence time along the screw profile. The influence of the operating conditions (feed rate, screw speed, barrel temperature) and screw profile was studied. Flow modeling was performed using the Ludovic© software and measured and calculated pressure, temperature, residence time, and energy consumption were compared. The values of the temperature close to the melting zone were overestimated by the model, which considers instantaneous melting upon the first restrictive screw element. If the program assumes that melting occurs at the screw location identified experimentally, a correct description of the temperatures along the screw profile is produced. The influence of the processing conditions (feed rate, screw speed, barrel temperature, screw profile) is well described by the model. These results put in evidence the importance of including an adequate melting model in the modeling of the twin‐screw extrusion process. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 1419–1430, 2000

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“…The discontinuous geometry of the kneading blocks can be replaced by a screw channel of an approximate pitch. For more details see also [10].…”

Section: Assumptionsmentioning

confidence: 98%

Theoretical and Experimental Investigations of the Melting of Pellets in Co-Rotating Twin-Screw Extruders

Potente

Melisch

1996

International Polymer Processing

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Knowledge of the plasticizing behavior in tightly intermeshing, co-rotating twin-screw extruders is of crucial importance for assessing the compounding process. Experiments were conducted on a laboratory extruder in order to establish the parameters that influence the melting process. Solidified samples of material were taken from the screw and microtome cuts produced from the plasticizing section. These were then assessed on the basis of image analysis. This visualization of the solid and molten phases which are present simultaneously together with the distribution of the two phases made it possible to quantify the reduction that occurs in the amount of solid material over the length of the screw configuration employed.A model is additionally presented for the calculation of the melting lengths and the melting profiles. This works on the basis of individual particles which are uniformly dispersed in the polymer melt. Allowance is made for the temperature increase in the solid material conveying section. A comparison of calculated and experimentally determined melting lengths revealed a satisfactory level of agreement.International Polymer Processing downloaded from www.hanser-elibrary.com by Kungliga Tekniska on August 20, 2015For personal use only.

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Design of Tightly Intermeshing Co-Rotating Twin Screw Extruders

Cited by 61 publications

References 5 publications

Investigating the impact of operating conditions on the extent of additive mixing during thermoplastic polymer extrusion

Investigating the impact of operating conditions on the extent of additive mixing during thermoplastic polymer extrusion

Experimental and theoretical study of twin-screw extrusion of polypropylene

Theoretical and Experimental Investigations of the Melting of Pellets in Co-Rotating Twin-Screw Extruders

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