New materials from waste and renewable oils
Sellars, Andrew B.
The work presented in this thesis represents the chemical modification of waste and renewable vegetable oils to yield monomers for polyurethane, azide-alkyne click and nitrile-oxide click polymerisations. Chapter 1 provides a brief introduction to use of waste materials for new products, following on to a more detailed overview of triglyceride chemistry, finishing with an introduction to ‘Click’ chemistry.\ud \ud Chapter 2 discusses the optimisation studies of acid catalysed ring-opening of epoxidised cocoa butter followed by polyurethane synthesis. Percentage of ring-opening was found to be influenced by the amount of phase-transfer catalyst, concentration of reaction and equivalents of acid. Mechanical properties (Young’s Modulus (YM), Tensile strength (TS) and Elongation at break (EoB)) were determined and thermal analysis (TGA, DSC) measured on cocoa butter based polyurethanes both with and without food-safe dyes as an alternative more environmentally friendly renewable oil source for polyurethane synthesis.\ud \ud Chapter 3 focuses on the use of azide-alkyne click chemistry to produce renewable polymers from dimeric fatty amides (capable of H bonding) with increasing linker length and azide functionality. Samples were synthesised from purified oleic acid and linoleic acid and cheaper, more commercially available rapeseed oil and soybean oil. Thermal properties (TGA, DSC) of copper mediated and thermally produced polymers were analysed and mechanical properties (YM, TS and EoB) of thermally produced polymers were also investigated showing increasing linker length increased elongation and decreased tensile strength and also showed the importance of H bonding between polymer chains drawn.\ud \ud Chapter 4 expands on azide-alkyne click polymerisation by synthesis of a range of monomers containing both azide and alkyne units therefore capable of homopolymerisation. Increasing chain length, azide functionality and hydrogen bonding possibilities were again tested using the same four starting materials as Chapter 3 as well as increasing cross-linking possibilities and results were found to compare with those established in Chapter 3.\ud \ud Chapter 5 concentrates on using nitrile oxide-alkyne click polymerisations as an alternative and safe method of producing renewable polymers derived from vegetable oils. Two approaches were used for polymerisations, base mediated and thermal mediated polymerisations with polymers produced subjected to thermal analysis (TGA, DSC).\ud \ud Chapter 6 describes the experimental and chemical analysis of the key reactions and processes described in the thesis.
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