Measuring the residence time distribution in a twin screw extruder with the use of NIR‐spectroscopy

Laske, Stephan; Witschnigg, Andreas; Selvasankar, Ramesh Kumar; Holzer, Clemens

doi:10.1002/app.39919

Cited by 13 publications

(8 citation statements)

References 22 publications

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“…On the other hand, twin-screw extruders are commonly used in modern industry [ 5 , 10 , 11 , 12 , 13 ]. Such extruders can be divided based on the relative rotational direction of their screws into two types: co-rotating and counter-rotating twin-screw extruders.…”

Section: General Remarksmentioning

confidence: 99%

The Modelling of Extrusion Processes for Polymers—A Review

2020

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Extrusion processes are widely used in industries that aim to produce advanced solutions for increasingly sophisticated demands in the plastic, food, and pharmaceutical sectors. Though the process has been in use since the 1930s, limited information is available on the analytical computation of extrusion. Generally, production has been carried out based on empirical experience and trial-and-error approaches. The development of industrial operations is, however, best addressed by modelling the processes involved, and the flow of polymer melts and fibers in extruders has been subjected to some previous studies. Also included an overview of design of a die as well as challenges in sheet/film production. This article systematically and critically reviews the literature related to the process design, machine design, process parameters, flow models, and flow analysis of extrusion with a focus on modelling the extrusion of composite materials.

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Section: General Remarksmentioning

confidence: 99%

The Modelling of Extrusion Processes for Polymers—A Review

2020

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“…In contrast, content uniformity of an API–matrix mixture can be improved by broadening the residence time distribution (RTD). Back mixing due to pressure gradients, dispersion by mixing elements, and wall adherence of material on the screw and barrel wall cause nonplug flow behavior during extrusion, resulting in a broader RTD . For reinforced polymers, the mechanical properties strongly depend on distribution of the filler, without damaging the matrix polymer chains .…”

Section: Introductionmentioning

confidence: 99%

“…Fluorescence spectroscopy was utilized as well, with tracers such as perylene and anthracene . Other measurement techniques include UV–vis , ultrasonic and near‐infrared (NIR) spectroscopy, NIR chemical imaging , and conductivity . In the latter publication, qualitative video analysis was performed to study flow phenomena caused by certain screw elements using glucose syrup with dark‐colored spherical particles in a translucent extruder .…”

Section: Introductionmentioning

confidence: 99%

In‐line measurement of residence time distribution in melt extrusion via video analysis

Wahl

Hörl

Kaiser

et al. 2017

Polymer Engineering & Sci

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Residence time distribution (RTD) is an important factor in melt extrusion as it strongly influences the product quality. It can cause degradation of the active pharmaceutical ingredient (API), which can be reduced by shorter mean residence times, and the content uniformity, which can be improved by broadening the RTD caused by axial mixing. In our study, we developed an inline video analysis that to date has mainly been applied offline. For extrusion, hydrophilic polymer and a surfactant were used as a molten matrix, in which an API was embedded. The video analysis consisted of four steps: (1) segmentation of the image to mask the strands, (2) calculation of average color values for the segmented pixels of each frame, (3) fitting of the obtained color curve with an analytical solution, and (4) calculating several RTD measures (e.g., the minimal and mean RT) for better comparison of the results. The RTD measures were responses in the design of experiments (DoE), which included the process parameters screw design, screw speed, and throughput. This analysis clearly showed that screw design had the strongest effect on the RTD measures. The results suggest that video analysis is a suitable tool for inline RTD measurements. POLYM. ENG. SCI., 58:170–179, 2018. © 2017 Society of Plastics Engineers

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“…Due to the above mentioned reasons, NIR spectroscopy has been widely used for nondestructive measurements in a variety of domains, such as food, [13,14] pharmacy, [15,16] petrochemical, [17,18] and chemical engineering. [19][20][21] Recently, chemometrics and machine learning methods further push forward the development of NIR spectroscopy, [22][23][24][25] which help to extract feature information from the spectra and serve as a basic tool for classification or regression. [26,27] A series of studies exist in the literatures that characterize the dispersion state using NIR spectroscopy.…”

Section: Introductionmentioning

confidence: 99%

In‐line characterization of dispersion uniformity evolution during a twin‐screw blending extrusion based on near‐infrared spectroscopy

Zhang

Lei

et al. 2020

Polymer Engineering & Sci

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Properties of an immiscible polymer blend have been proved to be closely related to dispersion uniformity of the minor phase. At present, dispersion uniformity is difficult to evaluate during the blending process, resulting in hysteretic feedback. Aiming at this problem, this work utilized near‐infrared (NIR) spectroscopy to in‐line characterize dispersion uniformity evolution during a twin‐screw extrusion. A multichannel NIR measurement system was set up and applied to evaluate the blending process of polypropylene and polyolefin elastomer (POE). Based on the NIR spectra collected at different positions of the extruder, five prediction models of POE content were established using the light gradient boosting machine algorithm. Dispersion uniformity was characterized through the fluctuation of the predicted content. The evolution of dispersion under such processing parameters was consistent with scanning electron microscopy.

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Measuring the residence time distribution in a twin screw extruder with the use of NIR‐spectroscopy

Cited by 13 publications

References 22 publications

The Modelling of Extrusion Processes for Polymers—A Review

The Modelling of Extrusion Processes for Polymers—A Review

In‐line measurement of residence time distribution in melt extrusion via video analysis

In‐line characterization of dispersion uniformity evolution during a twin‐screw blending extrusion based on near‐infrared spectroscopy

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