Abstract
This project aimed to expand the use of solvent-induced actuators to engineering disciplines with harsh environments, such as automotive, aerospace, and oil industries, and beyond the fields of biomedicine and soft robotics. While polymer-only actuators have been extensively studied in the literature, their weak mechanical properties prevent their use in industrial applications. Consequently, solvent-induced actuators based on natural fibre-reinforced polymers have attracted scientists' attention for their superior mechanical properties. However, their actuation response to water only limits their applicability in engineering fields where various solvents are employed. In this project, to address issues of poor mechanical properties and solvent insensitivities, polymers were reinforced with continuous carbon fibres and bi-layered structures with [0x/90y] lay-up sequences were created. Tailored fibre arrangement controlled the swelling of each layer upon exposure to different solvents. This approach mimicked pinecones' structure and opening and closing mechanisms in dry and humid environments, enabling us to achieve controlled bending of composites in response to solvent absorption. Our methodology involved identifying solvent-sensitive polymers using Hansen solubility parameters, fabricating composites by creating a series of fibrous prepregs via solvent casting, assembling prepregs into [0x/90y] lay-up sequences, and hot-pressing the assemblies, testing the manufactured composites in various fluids, and establishing theoretical models to predict the extent of composites' bending with solvent absorption. Maleated ethylene-propylene co-polymer (MA-EPR)and polyvinyl alcohol (PVA) were chosen for hydrocarbon and aqueous fluids. Fabricated composites demonstrated selectivity to identified fluids, and the model created by combining chemical and engineering theories facilitated good prediction of composite bending during solvent absorption. Additionally, due to how polymers were crosslinked, MA-EPR and PVA composites were found to
possess thermal recycling capabilities, enhancing their and composites' sustainability properties. One possible application of developed actuators is in structural health monitoring to detect damage to engineering structures due to fluid leakage.
| Date of Award | 1 Oct 2024 |
|---|---|
| Original language | English |
| Awarding Institution |
|
| Supervisor | Fabrizio Scarpa (Supervisor) & Neil A Fox (Supervisor) |