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This study was an investigation of the complex industrial PTFE polymerisation. Ex- periments were devised within the operating conditions to investigate the solubility of tetrafluoroethylene (TFE) in the hydrocarbon wax added to the polymerisation. Over the polyrnerisatlon pressures, the solubility of TFE in the wax varied from 5.6x10-2 mol dm-3 (1000 kPa) to 11.2x10-2 mol dm-3 (1310 kPa). The solubility was decreased by the pres- ence of ammonium perfluorooctanoate (APFO), a trend also observed for nitrogen. Four polytetrafluoroethylene (PTFE} polymerisations were performed to ascertain the effect of varying quantities of wax on the dispersion and polymer particles produced. No significant difference in molecular weight, particle size or particle crystallinity was observed. It has been proposed that the role of the wax is to aid solubilisation of TFE in the aqueous phase and it does play a pivotal role in the nucleation or growth mechanism of PTFE. It is theorised that PTFE particles change from rods to cobble-stone particles via a roll-up mechanism. Statistical analysis of the particle shapes and size was performed from electron microscopy images. No evidence for a roll-up mechanism was observed. The rate of polymerisation was investigated through a novel experimental procedure and the 1 st-order rate constant with respect to TFE was found to be of the order of 1 x 10-3 s-1. The addition of nitrogen to the autoclave reduced the rate of polymerisation substantially. 2,3,4,5,6-pentafluorostyrene (PFS) was chosen to develop a polymerisation recipe with the aim to mimic the PTFE polymerisation. A reproducible aqueous synthesis was developed and used to test fluorinated surfactants with and without the presence of wax. A method of determining the kinetics of polymerisation using gas chromatography-mass spectrometry was created. The addition of wax reduced the rate of all polymerisations as PFS was preferentially soluble in the wax over the aqueous phase.

This thesis reports the synthesis of polycaprolactone via ring-opening polymerisation of ϵ-caprolactone using alcohol/tin octanoate as the initiator/ catalyst system. The projects in this thesis aimed to investigate the polymerisation when it was conducted by the use of microwave heating and to develop new synthetic approaches for the synthesis of 3 dimensional structural polymers. Chapter 1: The fundamentals of ring opening polymer chemistry is discussed which is the polymerisation methodology employed in this thesis. In addition, the theory and background of microwave heating mechanism and application is also provided. Chapter 2: This chapter discusses the synthetic methods, equipment and characterisation techniques that are used in this thesis. Chapter 3: The practical work concerned with bulk microwave-assisted ring-opening polymerisation is discussed with the focus on the synthesis of linear polycaprolactone, using CEM reactor (microwave) which is operated at 2.45 GHz and an oil bath (conventional) to generate the energy input to the reaction. The investigation of the polymerisation kinetics, control characteristics, process optimisation and the effect of microwave on the reaction are also discussed in this section. This work clearly demonstrated that the polymerisations require a shorter cycle time when microwave heating was used and this has been as a result of the selective heating of certain reaction components. Chapter 4: The synthesis and characterisation of star polymers using both microwave and conventional heating is reported in this chapter. 3- and 4- arm star materials were successfully produced and again reaction times were shown to be reduced in the microwave reactions. Chapter 5: The investigation of a new synthetic approach for the synthesis of highly branched polycaprolactone is contained in this chapter. The branching copolymerisation reactions were conducted by polymerising ϵ-caprolactone in the presence of a di-lactone. The molecular structures of the polymers were also characterised by various methods which confirm the branched architecture.

Molecular imprinting is a technique for the preparation of synthetic molecular receptors capable of the selective recognition of given target molecules. Molecularly imprinted polymers (MIPs) offer several unique advantages over existing methodologies in analytical techniques such as facile preparation, low cost and superior stability. In recent times, applications of MIPs have been pursued in several areas including separation methods, ligand binding assays, catalysis and chemical sensors.

This thesis focuses on the use of both atom transfer radical polymerisation (A TRP) and reversible addition fragmentation chain transfer (RAFT) polymerisation for the synthesis of controlled-structure poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC}-based copolymers for biological applications. A TRP was used to prepare various fluorescent PMPC homopolymers, statistical copolymers and PMPC-poly(2-diisopropylamino)ethyl methacrylate) (PDPA) block copolymers. (Co)polymers were terminally labelled using a rhodamine 6G-functionalisecl ATRP initiator and statistical copolymers were prepared by copolymerising approximately one unit of either rhodamine 6G methacrylate, rhodamine B acrylate or the commercially available fluorescein-O-methacrylate per PMPC chain. Labelled copolymers prepared using the fluorescent methacrylic comonomers exhibited relatively low polydispersities for mean degrees of polymerisation up to 200. A post-polymerisation functionalisation technique was also used to attach commercially available thiol-reactive dyes to (co)polymers containing a central disulfide bond. Con focal microscopy studies revealed that efficient staining of human dermal fibroblast (HDF) cells was achieved within one hour incubation. Depending on the nature of the fluorescent label, organelle specificity was also observed: rhodamine labelled (co)polymers selectively stain the mitochondria, while fluorescein-labelled copolymers were distributed throughout the cellular matrix. MTT assays indicated negligible toxicity for all the (co)polymers after 24 h incubation at 37°C. Finally, uptake inhibition studies indicated that the internalisation pathway of the rhodamine-labelled polymers is energy-dependent and relies on recognition of the PC groups the (co)polymer chains by scavenger receptors on the cell surface. RAFT polymerisation was used to synthesise a series of PMPC macro-chain transfer agents (CTAs) using a range of RAFT CTAs. These syntheses were all well controlled with low polydispersity macro-CT As of varying molecular weights produced. After purification, selected PMPC macro-CTAs could be chain-extended with DPA to produce a series of pH-responsive amphiphilic diblock copolymers. By tailoring the relative block compositions and varying the preparation method, either spherical micelles, cylindrical (or worm-like) micelles or polymcrsomes could be produced. Using pH-induced self-assembly, it was only possible to form spherical micelles (PDPA DP:'S 59), polymersomes (PDPA DP ~ 77), or a mixture of the two phases (POP A DP = 67). Using both thin film rehydration and solvent-exchange techniques, it was also possible to form worm-like micelles. This was the major nano-structure observed when the PDPA DP was 67. Incubation of selected copolymers with HDF cells confirmed negligible cytotoxicity for all the copolymers, irrespective of end-group, DP or morphology. Moreover, it was also possible to deliver rhodamine B octadecyl ester to the HDF cells. These preliminary studies suggest that the internalisation kinetics may depend on the morphology of the nano-structures. Finally, the use of PMPC macro-CT As as steric stabilisers for the aqueous emulsion polymerisation of DPA was investigated. Using several PMPC25 macro-CTAs, a series of PMPC-PDP A nanolatexes were synthesised, for which the mean hydrodynamic diameter increased systematically with PDPA DP. The most stable formulations consisted of POP A DPs above 250. It was possible to encapsulate rhodamine B octadecyl ester during the synthesis of a PMPC2s-PDPA250 nanolatex and deliver it to HDF cells without causing significant toxicity (cell viability> 80 % after 24 h incubation at 37°C). Cross-linking such nanolatexes was achieved by addition of a small amount of dimethacrylate comonomer during the latex synthesis. This resulted in pH-responsive microgels that swelled on lowering the solution pH below approximately 6.5. Incorporation of a disulfide bond into the cross-linker made it possible to cleave the cross-links, causing the copolymer microgels to dissolve molecularly in acidic solution.