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Screw Extrusion as a Scalable Technology for Manufacturing Polylactide Composite with Graphene Filler

Kaczor Daniel, Bajer Krzysztof, Raszkowska-Kaczor Aneta, Krasinska Oksana, Domek Grzegorz, Szroeder Paweł

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 2

226--237

EN

The use of carbon nanomaterials as fillers in the process of obtaining polymer composites by extrusion poses many problems. The high agglomeration ability and low bulk density of carbon nanomaterials do not allow to easy production of composites characterized by very good dispersion of the filler in the polymer matrix, which is required to obtain a high-quality product. The advantage of this type of fillers is that the improvement of the composite properties can be achieved even at a low degree of filling. In this article, we describe a method for obtaining polylactide composites with a nanofiller in the form of graphene nanoplatelets. To overcome the difficulties associated with the use of graphene, we divided the process of obtaining composites into two stages. In the first stage, we made a masterbatch containing 25 wt.% graphene, from which, in the second stage, we obtained target composites containing from 0.1 to 2 wt.% graphene. A twin-screw extruder was used in both stages. The tested filling levels had no significant impact on the recorded processing parameters. The composites obtained by the described method are characterized by good dispersion of graphene. However the graphene agglomerates can be observed in the polymer matrix. Composites were tested by SEM, FTIR, DSC and MFR methods. Mechanical tests such as static tension, three-point bending, impact strength showed that the addition of 0.5 wt% of graphene improves tensile strength by 10 %, Young's modulus by 19 % and both flexural strength and flexural modulus by 15 %. The carbon filler has an impact on crystallization process of the polymer matrix by acting as a nucleating agent.

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Screw Extrusion as a Scalable Technology for Manufacturing Carbon Nanotube-Filled Polylactide Composites

Kaczor Daniel, Bajer Krzysztof, Raszkowska-Kaczor Aneta, Domek Grzegorz, Schroeder Paweł

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 3

99--110

EN

The bottleneck in the widespread use of carbon multiwall nanotube polymer composites is the lack of manufacturing technology that can be used on an industrial scale. In this article, we describe a two-step composite manufacturing technology based on screw extrusion that produces composites characterizing with good dispersion of carbon nanotube filler in polylactide matrix. The first stage involved the fabrication of highly filled masterbatches of 25 wt% of carbon nanotubes. In the second stage, by screw extrusion of the masterbatch mixture with neat polymer, we obtained homogeneous composites with the target filler concentration. The resulting composites with nanotube content ranging from 0.1 to 2 wt%. Mechanical tests including static tension, tensile strength, tensile modulus, three-point bending and impact strength has shown that optimal concentration of the carbon nanotube filler is ranged between 0.5 and 1 wt%. Samples were examined also by SEM, FTIR-ATR, DSC and MFR methods.

3

Introduction to modelling the correlation between grain sizes of feed material and the structure and efficiency of the process of co-rotating twin-screw extrusion of non-flammable composites with a pla matrix

Fiedurek Kacper, Szroeder Paweł, Macko Marek, Raszkowska-Kaczor Aneta, Borowicz Marcin, Puszczykowska Natalia

Acta Mechanica et Automatica

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2022

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Vol. 16, no. 4

301--308

EN

Co-rotating twin-screw extrusion is an energy consuming process that is generally not fully optimised to a specific polymer. From the point of view of the efficiency of the extrusion process, the starting material should be characterised by small grain sizes in comparison to the screw channel area, small surface area to volume ratio and small internal friction between the pellets. To develop a model describing the effect of polylactide (PLA) grain size on the extrusion efficiency, a series of experiments with a twin-screw extruder were carried out during which the energy consumption; torque on shafts and temperature of the melt on the extruder die were monitored. As feed material, both the neat PLA with different grain sizes and the PLA with expandable graphite fillers and phosphorous-based flame retardants were used. Morphology and dispersion quality of the composites were examined using scanning electron microscopy (SEM); flammability, smoke production, mass loss and heat release rates were tested using cone calorimetry; and melt flow rate was determine using a plastometer. Moreover, the thermal properties of the obtained composites were determined using differential scanning calorimetry (DSC). The results show that the choice of the starting material affects both the efficiency of the extrusion process and the flame retardancy properties of the composite materials.

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Influence of extruder plasticizing systems on the selected properties of pla/graphite composite

Kaczor Daniel, Bajer Krzysztof, Domek Grzegorz, Madajski Piotr, Raszkowska-Kaczor Aneta, Szroeder Paweł

Acta Mechanica et Automatica

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2022

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Vol. 16, no. 4

316--324

EN

Twin-screw extrusion is a crucial method for the direct inserting of carbon micro- and nanomaterials into a polymer matrix using a dry procedure. The study aimed to determine the influence of the parameters of the twin-screw extruder plasticizing system on the dispersion homogeneity and distribution of graphite filler in the polylactide polymer matrix and overall quality of the composite. As a filler, a graphite micropowder with a 5 μm lateral size of platelets was used at concentration of 1 wt.%. Three configurations of screws with different mixing intensity and various types segments were considered in the extrusion experiments. Morphology and chemical structure of the obtained composites were examined using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy – attenuated total reflectance (FTIR-ATR) and Raman spectroscopy. Differential scanning calorimetry (DSC) and melting flow rate measurements (MFR) were used to asses thermal and rheological properties of the composites. Samples of the polylactide/graphite composites were also subjected to mechanical tests. The results show that the selection of the mechanical parameters of twin-screw extruder plasticizing system plays a key role in the preparation of the homogeneous PLA/graphite composites. Incorrect selection of the screw geometry results in poor mixing quality and a significant deterioration of the mechanical and thermal properties of the composites. Optimised mixing and extrusion parameters can be the starting point for the design of efficient twin-screw extruder plasticizing system for fabrication of PLA composites with carbon nanotube and graphene fillers.

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Nowy aparat do oznaczania tlenu i dwutlenku węgla w Laboratorium Badawczym "Polimer"

Raszkowska-Kaczor Aneta, Kaczor Daniel

Laboratorium - Przegląd Ogólnopolski

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2021

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nr 3

22--26

PL

W artykule omówiono możliwości użytkowe, parametry techniczne oraz zastosowanie nowo zakupionego w Laboratorium Badawczym "Polimer", należącym do Łukasiewicz - Instytutu Inżynierii Materiałów Polimerowych i Barwników, analizatora do oznaczenia przenikalności tlenu i dwutlenku węgla do badania folii płaskich i opakowań 3D. Omówiono schemat działania urządzenia oraz jego praktyczne zastosowanie. Zaprezentowano wyniki badań przenikalności tlenu i dwutlenku węgla dla wybranych, dostępnych na rynku laminatów o różnym składzie.

EN

The article discusses the usability, technical parameters and application of an analyser newly purchased by the Research Laboratory "Polymer", belonging to the Łukasiewicz Research Network - Institute for Engineering of Polymer Materials and Dyes, for determining the permeability of oxygen and carbon dioxide for testing flat films and 3D packaging. The operational scheme of the device and its practical application ore discussed. The test results of the permeability of oxygen and carbon dioxide for selected laminates of various compositions available on the market are presented.