Polymers were synthesised containing the methanoanthracene (MA), methanopentacene (MP) and benzomethanoanthracene (BzMA) units to investigate their properties as gas separation membranes. For each monomer type, polymers were successfully synthesised using Tröger’s base (TB) chemistry and cast as free standing films from low-boiling point solvents. Gas permeability tests revealed high selectivities for most of the technologically significant gas pairs. Most interestingly, MA/dimethylethanoanthracene co-polymer, MP-TB and BzMT-TB polymers all show a high degree of selectivity in the separation of a number of technologically significant gas pairs when compared to other state-of-the-art polymers. In particular MP-TB has very high selectivity for the N2/O2 gas pair. Synthetic routes to MP-TB and BzMA-TB involve fewer steps and are significantly cheaper to implement compared to other state of the art TB polymers and high performance PIMs that provide data above the Robeson upper bounds due to their high permeability and selectivity. Co-polymers of MA were synthesised in 1:1, 4:1 and 9:1 ratios. Gas permeability data demonstrated that properties correlate with the monomer composition. Results indicate that inclusion of methano-bridged units into the polymers increased the rigidity of polymer chains, leading to smaller pore widths and improved selectivities compared to polymers such made from more flexible structural units. The first chapter of this thesis introduces the concepts of microporosity, permeability and membrane separation, and describes a number of polymers that have demonstrated properties of interest for separating gas mixtures. Chapter two describes the synthesis and gas permeability data of MA-TB polymer and a series of copolymers incorporating MA. Chapter 3 describes the synthesis of polymers containing the MP structural unit and describes the performance of MP-TB as a membrane for gas separation. Chapter 4 describes a number of polymers synthesised using the BzMA structural unit and chapter 5 reports the synthesis of a number of larger units derived from BzMA including benzomethanotetracene, benzomethanopentacene and dibenzomethanopentacene. Permeability data for TB polymers synthesised from BzMA-type monomers is reported in these chapters.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:738901 |
| Date | January 2017 |
| Creators | Williams, Rhodri John |
| Contributors | McKeown, Neil ; Cowley, Michael |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/28924 |
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