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Improving the accessibility of transition metal mediated radical polymerization
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Marathianos, Arkadios (2021) Improving the accessibility of transition metal mediated radical polymerization. PhD thesis, University of Warwick.
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Official URL: http://webcat.warwick.ac.uk/record=b3764596
Abstract
This PhD thesis aims to bring new perspectives on the field of Transition Metal Catalyzed Polymerization methods, by investigating alternative synthetic approaches for the generation of various polymers, many of which having high prospect for industrially related use. For this purpose, two distinctive transition metal catalyzed polymerization methods, namely Catalytic Chain Transfer Polymerization (CCTP) and Copper-mediated Reversible Deactivation Radical Polymerization (Cu-RDRP) were examined under various conditions, and used for the generation of polymers which either have compelling applications or are well-defined. For simplicity, this thesis can be divided into two parts; the first part focuses on the use of CCTP in combination with surfactant-free emulsion polymerizations (Chapter 2 and Chapter 3). The second part which focuses on Cu-RDRP, aims to examine the limits of this controlled radical polymerization method under the simultaneous introduction of oxygen tolerance and either continuous flow chemistry or the use of a bio-renewable solvent (Chapter 4 and Chapter 5).
Initially, the ability of CCTP-derived methacrylic macromonomers to act as stabilizers in surfactant-free emulsion polymerizations was investigated (Chapter 2). Although these macromonomers are highly versatile, studies on their behaviour as stabilizers in emulsion processes had been limited. In Chapter 2, ionic and non-ionic CCTP-synthesized oligomers were compared with a conventionally used surfactant (SDS) for their stabilizing effect on surfactant-free emulsion polymerization of hydrophobic monomers. The effect of the stabilizers (ionic vs non-ionic vs low molar mass surfactants) on the properties of the final product was examined and with the alliance of different characterization methods, a statistical method explaining the particle size variations due to the hydrophobic monomer selection was created.
In Chapter 3, the potential use of this type of macromonomers in industrial applications (e.g. in agrochemical industry) was examined. Specifically, amphiphilic macromonomers obtained through CCTP with varying acid content, were used for the development of stable aqueous dispersions of an active ingredient (AI), namely cyantraniliprole (CYNT). Upon finding the optimum conditions for sufficient CYNT dispersion, the direct application of polymeric coating around the CYNT particles was investigated. For this purpose, surfactant-free emulsion polymerization of a monomer mixture under starved-feed conditions was carried out in the presence of the CYNT dispersion. Finally, the release profile of cyantraniliprole in aqueous media was investigated.
The second part of this dissertation was focused on a different type of Transition Metal Catalyzed Polymerization, namely Cu-RDRP. In this part of the thesis (Chapter 4 and Chapter 5), the limits of this versatile controlled radical polymerization process were examined under various conditions. Specifically, in Chapter 4, the photoinduced Cu-mediated polymerization of different acrylates in a continuous flow reactor was investigated without conventional deoxygenation, hence providing a simplification of the existing continuous flow approaches. Upon optimization, well-defined poly(acrylates) were synthesized with a range of molar masses and low dispersity values. Importantly, although in continuous flow and in the presence of air/oxygen, the synthesized polymers exhibited high end-group fidelity, as confirmed through efficient post polymerization modification. The oxygen tolerant nature of Cu-RDRP was further examined in Chapter 5, this time in batch and with the use of a bio-renewable solvent (CyreneTM), along with the use of very low catalyst loadings. Well-defined polymers with good macromolecular characteristics were obtained, providing an environmentally-friendly alternative synthetic way.
Item Type: | Thesis (PhD) | ||||
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Subjects: | Q Science > QD Chemistry T Technology > TP Chemical technology |
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Library of Congress Subject Headings (LCSH): | Polymerization, Transition metal catalysts, Addition polymerization | ||||
Official Date: | August 2021 | ||||
Dates: |
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Institution: | University of Warwick | ||||
Theses Department: | Department of Chemistry | ||||
Thesis Type: | PhD | ||||
Publication Status: | Unpublished | ||||
Supervisor(s)/Advisor: | Haddleton, David M. | ||||
Format of File: | |||||
Extent: | xxxviii, 252 leaves : illustrations | ||||
Language: | eng |
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