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Identifier

000464661

Title

MXenes: σύνθεση και ανάπτυξη πολυμερικών νανοσύνθετων υλικών

Alternative Title

MXenes: synthesis and development of polymer nanocomposite materials

Author

Θώμος, Αλέξανδρος Γ.

Thesis advisor

Αναστασιάδης, Σπύρος

Reviewer

Χρυσοπούλου, Κυριακή
Στυλιανάκης, Μηνάς

Abstract

Nanocomposite polymers have been the focus of interest in the research community in recent years due to their improved properties compared to their precursors. In the present work, nanohybrids in different compositions containing polyethylene oxide (PEO) of different molecular weights and MXenes were synthesized under different time and temperature conditions. The first part of the work concerned the synthesis of MXenes, which are new and promising materials for use in various applications. The synthesis started from the MAX precursor material by chemical etching using HCl and NaF. Initially the synthesis was based on conditions defined in the literature and then the effect of temperature and time on the reaction was studied to optimize the conditions. All materials were characterized in terms of structure, morphology and elemental composition by X-ray diffraction (XRD), scanning electron microscopy coupled with elemental analysis by X-ray energy dispersive spectroscopy (SEM/EDX) and transmission electron microscopy (TEM) through which the synthesis of high quality and purity materials was confirmed. In the second part of the work, the synthesis of the nanohybrids was carried out, by first determining the appropriate way of their preparation. Then the polymers of different molecular weights were mixed with MXene from the different successful syntheses at different compositions at different compositions, to study how the structure and thermal properties of the nanocomposites are affected. In all cases, the nanomaterials exhibited an interference structure whose characteristics, as evidenced by XRD measurements, are not strongly affected by the factors investigated. Furthermore, Differential Scanning Thermodynamic Composition (DSC), used to study the thermal properties, showed a strong effect of composition mainly on the crystallinity percentage of PEO, while the critical melting and crystallization temperatures remain relatively stable. Finally, the presence of MXene in the nanocomposite appears to lead to increased thermal stability as it creates an additional decomposition step at a higher temperature, but both decomposition steps appear to be affected by increasing the percentage of MXene.

Language

Greek

Subject

Crystallization Temperature and Decomposition temperature

Intercalated structure

Melt Temperature

Nanocomposites materials

PEO

Thermal properties

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