Saudi Cultural Missions Theses & Dissertations
Permanent URI for this communityhttps://drepo.sdl.edu.sa/handle/20.500.14154/10
Browse
1 results
Search Results
Item Restricted Clicking Towards Sustainability: Synthesis of Poly(isoxazole)s from Biomass via Nitrile Oxide/Yne Polymerisation(Saudi Digital Library, 2023-11-01) Alhathir, Abdulrahman Saad; Clark, AndrewClick chemistry has been a reliable, selective, and simple synthetic method for incorporating heteroatoms in polymer chemistry and material science. Poly(isoxazole)s can be prepared by the polycycloaddition of two clickable monomers, such as nitrile oxides and dialkynes. In addition, the potential of further modifying poly(isoxazole) structures through ring-opening is a promising area of research. However, the synthesis of poly(isoxazole)s from sustainably sourced materials, such as vegetable oils and lignins, has not been well studied. To address this, novel isoxazole-containing model compounds of poly(isoxazole)s derived from renewable stearic acids (C17H35CO2H) and vanillin-based substrates with various chemical structures were initially synthesised using nitrile oxide click chemistry. The reductive cleavage of the N-O bonds in the rings of isoxazole compounds was studied and successfully achieved using several reducing reagents, including Mo(CO)6 and Raney-Ni, for post-polymerisation modification. Subsequently, novel stearic acid- and vanillin-based poly(isoxazole)s were prepared through the click polycycloaddition between dipolarophilic dialkyne monomers and in situ generated aromatic nitrile oxides using step-growth polymerisations. The polymerisation was conducted under copper-mediated and base-mediated conditions. The highest molecular weight polymers were obtained under free-catalyst polymerisation conditions by employing environmentally-friendly solvents such as ethanol and THF. Finally, the post-polymerisation modification of the prepared stearic acid- and vanillin-based poly(isoxazole)s using Raney-Ni conditions resulted in partial success in achieving the intended cleavage reactions and the formation of desired poly(-enaminoketone)s. Overall, this thesis contributes to the understanding of poly(isoxazole) synthesis from renewable sources. The findings highlight the potential of sustainably sourced materials for polymer synthesis and the importance of optimising reaction conditions for desired polymer properties.29 0