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Identifier

000466045

Title

Μελέτη της κρυστάλλωσης σε Bottlebrush συμπολυμερή

Alternative Title

Crystallization in Bottlebrush copolymers

Author

Μαρκοζάννε, Γεωργία Α.

Thesis advisor

Αναστασιάδης, Σπύρος

Reviewer

Χρυσοπούλου, Κυριακή
Βαμβακάκη, Μαρία

Abstract

Polymer brushes are a class of polymers that have attracted considerable research interest because of their properties and their wide range of applications. In the present work, the crystallization of bottlebrush copolymers, a subclass of polymer brushes, which consist of (poly 2 (dimethylamino ethyl methacrylate) PDMAEMA, as the backbone and methoxy poly(ethylene glycol) mPEG, as the side chains was studied. In the first part of work, the thermal and structural characterization of the PDMAEMA (M.W. : 44000 g/mol) and mPEG (M.W. : 500, 1000, 2000 and 5000 g/mol) homopolymers was investigated using Differential Scanning Calorimetry (DSC), Small and Wide Angle X-ray Diffraction (SAXS-WAXS), Thermogravimetric Analysis (TGA) and Fourier Transform Infrared Spectroscopy (FTIR). In the same way, mPEG homopolymers, which were appropriately functionalized to have Bras a ligand, were characterized, as well. The bromination process of these homopolymers is necessary to assist the binding of mPEGs as side chains to the backbone of the bottlebrush polymers. In the second part of this work, the study of bottlebrush polymers, which have PDMAEMA as backbone and PEG of the same molecular weight as side chains (single brushes) that carry Bras a counter ion was performed. Four different single brushes, one for each mPEG molecular weight, were studied in order to investigate the effect of grafting as well as the PEG molecular weight on the crystallinity and the overall thermal properties of the mPEGs, utilizing DSC, the structural properties of the bottlebrush copolymers were studied using SAXS-WAXS. Subsequently, the study of three series of bottlebrush copolymer (mixed brushes), with PDMAEMA as backbone and mixture of mPEG500/mPEG1000, mPEG500/mPEG2000 and mPEG500/mPEG5000 as side chains in a wide range of compositions of the two mPEGs, was carried out. The investigation purpose of this study was to investigate whether a mixture of mPEGs of different molecular weights as side chains can affect further their crystallinity. The investigation of the crystallinity in these systems was carried out using DSC, as well. For the mixed brushes, the mechanism of crystallization of the mPEGs was investigated through isothermal crystallization kinetic measurements using the DSC technique, whereas their structure was studied using SAXS-WAXS. In addition, ATR-FTIR was utilized to verify the chemical stability of the single and mixed brushes following the repeated DSC cooling and heating cycles. 4 Further than the effect of the molecular weight and the composition of the side chains on the copolymer crystallinity, the effect of the size of the counter ion was investigated, as well using PF6 which is larger in size than Br^-.

Language

Greek

Subject

Crystallinity

PDMAEMA

Polymer brushes

Structure

Thermal properties

mPEG

Δομή

Θερμικές ιδιότητες

Κρυσταλλικότητα