POLİ(ETİLEN-ARD-MALEİK ANHİDRİT)/POLİ(ETİLEN GLİKOL) KARIŞIMI TEMELLİ TABAKALI SİLİKAT NANOKOMPOZİTLERİN HAZIRLANMASI VE KARAKTERİZASYONU

Abstract

ABSTRACT

PREPARATION AND CHARACTERIZATION OF POLY(ETHYLENE-ALT-MALEIC ANHYDRIDE)/POLY(ETHYLENE GLYCOL) BLEND BASED LAYERED SILICATE NANOCOMPOSITES

Mustafa Levent BOZDAĞ

Master of Science, Department of Chemistry Supervisor: Assoc. Prof. Dr. Serap KAVLAK June 2024, 97 pages

Polymer/layered silicate nanocomposites, an important class of polymer-based nanomaterials, can provide significant effects on the structural, thermal and mechanical properties of the polymeric materials into which they are incorporated. Blends of various polymers with functional groups prepared with other polymers with different properties provide great advantages as new materials with their structure-properties, intra- and intermolecular interactions. Polymer blends can also be used in the preparation of polymer/layered silicate nanocomposites like polymers. Thus, new and versatile polymeric nanomaterials can be developed with an easy and low-cost method.

In this work, it was aimed to prepare and characterize polymer blend/layered silicate nanocomposite materials using poly(ethylene-alt-maleic anhydride) (poly(E-alt-MA)) and poly(ethylene glycol) (PEG) polymers, which have functional groups and were selected due to their important properties that enable them to be used in biomaterial applications. Polymer blends and polymer blend/layered silicate nanocomposites consisting of poly(E-alt-MA) and PEG with different molecular weights and organically modified montmorillonite clay, used as nanomaterials at 1%, 4% and 8% by weight, were prepared by solution mixing and solution casting/solvent evaporation methods. The structures of the prepared polymer blends and polymer blend/layered silicate nanocomposites were investigated by ATR-FTIR spectroscopy and XRD techniques and the formation of nanocomposite structures was clarified. It was observed that the nanocomposites had a considerably exfoliated structure at low clay percentage (1%), while they generally had an intercalated structure at higher clay percentages (4 and 8%). The chemical structures of the nanocomposites and the interaction/compatibility of polymer blends with organically modified montmorillonite were interpreted by comprehensive spectral analysis of the characteristic bands of the groups in the structures.

The effects of different percentages of nano additive on the thermal and dynamic mechanical properties of polymer layered silicate nanocomposites were investigated using TGA, DSC and DMA techniques. Although it is generally seen that the thermal stability in nanocomposites is quite close to or higher than that of the polymer blend, higher thermal stability, which increases with the increase in clay percentages, has been observed especially in nanocomposites prepared with PEG with 8000 molecular weight. Melting temperatures and enthalpy values for polymer blends and nanocomposites were also interpreted comparatively. The dynamic mechanical properties and thermal transitions of the materials were investigated with various parameters and the effects of the nano additive were interpreted.

In line with the data obtained, it was evaluated that the compatibility between polymer blends and clay was more affective in polymer blend/layered silicate nanocomposites containing PEG with an 8000 molecular weight. As a result of this study, new nanomaterials with functional groups were obtained through the production and characterization of polymer blend/layered silicate nanocomposite structures, and their structural, thermal and dynamic mechanical properties were elucidated.

Keywords: Polymer blend, layered silicate, nanocomposite, structure-property relationships, thermal properties