Synthesis, Characterisation And Determination Of Mesophase Transition Of Cyclotriphosphazene Derivatives With Azo Linking Unit

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dc.contributor.authorLoh, Miyeko Lotus Leh Ching
dc.date.accessioned2019-08-27T01:46:34Z
dc.date.available2019-08-27T01:46:34Z
dc.date.issued2017-07
dc.description.abstractA series of intermediates were synthesised via azo coupling reactions to give the alkylated compounds with one azo linking unit, 2a-c and with two azo linking units, 5a-c. These intermediates were subjected to further monosubstitution and hexasubstitution reactions with cyclotriphosphazene to produce a series of final compounds 7a-f. These compounds were characterised using FT-IR (Fourier Transform Infrared), 1D and 2D NMR (Nuclear Magnetic Resonance) spectroscopy and CHN elemental analysis. Intermediates 2d-f and 4a-c were found to be mesogenic with nematic and smectic phases, as determined under the POM (Polarised Optical Microscopy). The endotherms obtained from the DSC (Differential Scanning Calorimetry) showed the respective phase transitions of crystal-mesophase, mesophase-mesophase if any, and mesophase-isotropic phases during the heating cycle; and vice versa during the cooling cycle. The influence of terminal groups and linking groups on mesogenic properties was discussed. Smectogenicity was found to be enhanced with increasing alkoxy chain length. Mono- and hexa-substituted compounds 7a-f were found to be non-mesogenic. It was concluded that the introduction of non-mesogenic side arms resulted in the lack of liquid crystalline properties in 7a-f.en_US
dc.identifier.urihttp://hdl.handle.net/123456789/8674
dc.language.isoenen_US
dc.publisherUniversiti Sains Malaysiaen_US
dc.subjectDetermination of mesophase transition of cyclotriphosphazeneen_US
dc.subjectderivatives with azo linking uniten_US
dc.titleSynthesis, Characterisation And Determination Of Mesophase Transition Of Cyclotriphosphazene Derivatives With Azo Linking Uniten_US
dc.typeThesisen_US
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