Summary: | This thesis describes the conventional free radical and RAFT polymerisation in supercritical carbon dioxide (scC02) expanded phase and polymerisation of isoprene towards the synthesis of squalene. Chapter 1 gives a general introduction to the methods employed in this thesis. This chapter is consisted of two parts: polymerisation techniques and polymerisation in SCC02. Since the main technique used in this work includes reversible addition fragmentation chain transfer (RAFT), atom chain transfer polymerisation (ATRP) and catalytic chain transfer polymerisation (CCTP), a thorough description of these methods are provided. Furthermore, as SCC02 is used, its features and applications are described. Chapter 2 provides a description of the experimental process and the analytical techniques adopted in this project. The high pressure vessels are described in detail. Chapter 3 explores the free radical polymerisation (FRP) with a conventional chain transfer agent (CTA) - dodecyl mercaptan (DDM) in scC02 expanded phase. The molecular weight effect on this system is discussed. Polymerisations were conducted with various monomer/scCO2 ratios, temperatures and pressures. A range of monomers are explored, including methyl methacrylate (MMA), styrene, vinyl acetate (VAc), vinyl pivalate (VPi) and acrylic acid (AA). The morphology and appearance of the products are also discussed. This work is extended to controlled/pseudo-living radical polymerisation using RAFT as control agent. The reactions are conducted with different target molecular weights. The polymerisation kinetics and end-group functionality are examined. Finally, the thermal stability of products is compared with the DDM terminated polymers. Chapter 5 describes the synthesis of poly(isoprene) (PI) to replace squalene/squalane for cosmetic applications. The reactions are conducted in both conventional solvents and scC02 expanded phase. Different polymerisation techniques are used, including CCTP, RAFT, ATRP and RATRP. The CCTP process is successfully scaled up and the products are hydrogenated to yield squalane for application tests. Chapter 6 summarises the research presented in this thesis and overall conclusions are provided.
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