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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

2024

Vol. 18, no 2

226--237

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.

Study of Crystalline and Thermal Properties of Nanocomposites Based on Polyamide-6 and Modified Montmorillonite

Krasinskyi Volodymyr, Dulebova Ludmila, Gajdoš Ivan, Krasinska Oksana, Jachowicz Tomasz

Advances in Science and Technology. Research Journal

2023

Vol. 17, no 6

88--97

The main operational characteristics of polyamide-6-montmorillonite (PA6/MMT) nanocomposites, which determine their fields of application, mainly depend on the crystal structure and crystallinity of the polymer. Therefore, the study of the crystalline behavior of PA6 in such nanocomposites is of considerable scientific and practical importance. In this work, the structure, crystalline, and thermal properties of nanocomposites based on PA6 and modified MMT prepared in a formic acid solution were investigated using the methods of differential scanning calorimetry (DSC) and X-ray Diffraction (XRD). It was established that during the manufacture of PA6/MMT nanocomposites in a solution, the dominant crystal structures are the thermodynamically stable α structures of PA6. The crystallinity degree of PA6 in nanocomposites is about 1.5 times higher than that of the original PA6. It is shown that after additional thermomechanical treatment of nanocomposites on a capillary viscometer at 230°С and a load of 5 kg, the uniformity of the distribution of exfoliated MMT in the polymer matrix increases, as a result of which the crystalline structure of PA6 changes and its glass transition and melting temperatures increase. These changes in the PA6 structure also have a significant impact on the melt flow index and the softening temperature of nanocomposites.