| Summary: | Cellulose and chitin are considered to be the most abundant, sustainable and environmentally-friendly polymers. They are, however, not utilized for large-scale applications due to their poor solubility in most traditional solvents, which makes them difficult to extract and shape into a desired product. Ionic liquids can effectively dissolve cellulose and chitin with less environmental impact than the traditionally used solvents. In this thesis, a manufacturing method has been developed for regenerating cellulose and chitin fibres with good mechanical properties and multi functional properties, using ionic liquids as environmentally benign solvents. In the first part, the study focused on the dissolution of cellulose, regenerating continuous cellulose fibres through dry-jet wet spinning, and characterising fibres' properties. In the second part, the study focused on imparting multi-functionality on cellulose fibres, by dispersion of electrically conducting particles such as carbon nanotubes and carbon black. An experiment was designed with different extrusion and winding velocities to determine the factors affecting fibres' conductivities during fibre spinning. This study provided useful guidelines for improving the degree of nanotube dispersion in cellulose fibres, electrical conductivity of cellulose composite fibres and their potential for use in other applications, such as conducting textiles and implantable electrodes for stimulation of tissues. In the third part, the study focused on producing high modulus cellulose fibres from an optically birefringent solution of cellulose. The resulting fibres demonstrated high level of alignment of cellulose chains along the axis direction. This study has immense potential to reshape the composites industry by introducing sustainable, environmentally benign and renewable fibres with enhanced mechanical performance. In the last part, the same manufacturing method for cellulose was used for chitin in order to demonstrate the wider scope of the technique. This study will be potentially useful for medical applications of chitin fibres in tissue regeneration and for wound sutures.
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