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The research reported in this thesis has been divided into five separate categories - Synthesis of dialkali metal silanediolate and siloxanediolate salts, - Synthesis of siloxane copolymers using interfacial condensation polymerisation, - Synthesis of silicon-organic copolymers using interfacial condensation polymerisation, - Investigation into the analysis of polymers using size exclusion chromatography, and - Theoretical investigation into TMDSC analysis of polymers. / Thesis (PhDAppliedScience)--University of South Australia, 2000.

Natural-synthetic hydrid biomaterials have been isolated from the growth of Alcaligenes latus and Pseudomonas oleovorans in the presence of diethylene glycol (DEG). A. latus could cometabolise DEG with 10 g/L glucose, while DEG was consumed by P. oleovorans with 20 mM sodium octanoate or octanoic acid. The presence of DEG in bioprocessing systems for the production of short chain length (scl-) and medium chain length (mcl-) PHAs consequently lowered cell viability and PHA yield. Cell morphology was slightly changed, but the PHA inclusion bodies apparently were not. DEG affected the composition of the mclPHA which was confirmed to be polyhydroxyoctanoate (PHO) with a significant increase in the C8 component. Gas chromatography-mass spectrometry (GC-MS) was used to quantitatively monitor DEG in the system and revealed its cellular adsorption. Intracellularly, the DEG significantly decreased the molar weight of the mclPHA and sclPHA. P1PH NMR, 2-D COSY and HSQC spectra confirmed that the polymer samples consisted of PHA chains terminated by DEG. Similar to the cultivation of P. oleovorans with DEG, the presence of PEG200 and PEG400 also had an effect on cell growth, PHO yield and cell viability. Furthermore, a hybrid copolymer of PHO-PEG200 was synthesised. The synthesis of these natural-synthetic hybrid copolymers could lead the way for a wide variety of PHA-PEG copolymers with a range of bioactive properties. All thermal properties of PHB were higher than those of PHB-DEG. This may be due to a combination of lower PHB molecular weight and termination of the chains by DEG, i.e. ???DEGylation???. However, PHB-DEG was more elastomeric when compared to PHB, showing properties similar to its copolymer with 20 mol% 3-hydroxyvalerate. Contact angles revealed that the PHB-DEG film was slightly more hydrophilic than PHB. Despite the large difference in their respective proportions, the comparatively small DEG component exerted an influence on chain confirmation, such that solvent casting under humid conditions apparently induced self-assembly and formed a disordered microporous film. DEGylation of PHO also had noticeable effects on the physiochemical properties of the biopolymer. A major decrease in molecular weight, together with the termination of hydrophobic PHO chains with hydrophilic end-groups resulted in changes to its thermal properties when compared to PHO. In comparison to PHO, solvent cast films of PHO-DEG were apparently less flexible, but more hydrophilic.

The synthesis of amine end-functionalised polymers by controlled free radical techniques has been investigated with a focus on methods that provide primary amino end-functionalised polystyrene. The aim of these investigations was to provide precursors to block and graft polyolefins and polyesters by interchain coupling reactions. The approaches investigated involved developing strategies for the synthesis of phthalimido-functional polymers which can be quantitatively deprotected to yield the desired amino-functional polymers. Initially synthesis by atom transfer radical polymerisation (ATRP) was explored. A number of approaches based on ??-functionalisation (end-group substitution) and ??-functionalisation (functional initiator) were examined. A novel ATRP initiator, N-bromomethylphthalimide, provided the most promising results but still had limited applicability because of its low solubility in polymerisation media. The problems encountered with the ATRP approaches prompted an exploration of techniques based on reversible addition fragmentation chain transfer (RAFT) approach. Novel phthalimidomethyl RAFT agents (trithiocabonates, xanthates) were synthesized. The activity and scope of the new RAFT agents was investigated in polymerisations of styrene, n-butyl acrylate, Nisopropylacrylamide, N-vinylpyrrolidone (trithiocarbonate) and vinyl acetate (xanthate). The syntheses of ??-phthalimidomethylpolystyrene were successfully scaled up and hydrazinolysis afforded a range of ??- aminomethylpolystyrenes of low polydispersity and controlled molecular weight. The syntheses of primary amino-functional polymers using the pthalimidofunctional RAFT agents necessitated the development of a convenient method for conversion of trithiocarbonate groups to inert chain ends. Thermolysis proved a most simple and efficient method of achieving this for both polystyrene and poly(n-butyl acrylate). Thermolysis also provided a means of further characterising the mechanism of the RAFT process. A simple and efficient method for amino end-group analysis was developed that involved in-situ derivatisation with trichloroacetyl isocyanate followed by 1H NMR analysis. The method was shown to be a suitable method for determining a wide range protic end-groups (NH2, OH, COOH) in synthetic polymers. Finally, metallocene polyolefin based coupling trials largely with controlled amino-functional polystyrene were conducted as an initial investigation into the production of high value added grafted polyolefins (and polyester). The grafting trials were carried out on a small scale with a view to directing future experiments.

In recent times, it was divulged that highly ordered honeycomb structured porous films from a variety of polymers could be fabricated by breath figures (water droplets) templating technique. In contrast to existing macroporous fabrication techniques, this technique is simple, more versatile and very cost effective. Amphiphilic block copolymers composed of a hydrophobic and a hydrophilic block were employed in this research to examine the process of porous film formation and the outcome of films generated using breath figure technique. A customized film casting system, established according to the casting parameters affecting the outcome of films was used to generate honeycomb structured porous films for the studies. The casting method best suited to generate highly ordered honeycomb structured porous films and the procedures to manipulate the size of the pores in films generated from amphiphilic block copolymers were also investigated and identified. Analyses into the formation process of the honeycomb structured porous films revealed that the airflow casting method where the cast of polymer solution was supplied with a flow of moist air was the most suitable method to generate highly ordered honeycomb structured porous films from amphiphilic block copolymers. Variations to the casting conditions of the airflow casting method such as the rate of moist airflow could only provide limited alterations to the size of pores on films generated. However, changes to the chemical system of the casting solution such as the concentration and the molecular weight of polymers in the polymer solvent was more prominent in manipulating the size of pores in the generated films. On the other hand, any extreme variations to either the physical conditions or the chemical system could devastate the hexagonal arrangement of pores in these films. In the synthesis of amphiphilic block copolymers in this research, RAFT polymerization technique was used to generate the hydrophobic polymer block followed by the subsequent chain extension polymerization of the hydrophilic polymer block. The polymerization 'process, especially the hydrophilic chain extension polymerization, was investigated in details. It was established that there were significant dependence on the composition of the initial polymer block used, particularly the molecular weight and the type of chain transfer (RAFT) end group in the hydrophobic polymer chain. Incompatible RAFT end group and high polymer molecular weights of the initial block usually lead to slower rate of subsequent chain extension coupled with increased terminations. These copolymers generated were usually bimodal in molecular weight distributions and broad in polydispersity indexes. Honeycomb structured porous films generated from one of these amphiphilic block copolymers were assessed as scaffoldings for cell culture to regenerate cells. In particular, the effects of cellular attachments and proliferations on the honeycomb porous structures were investigated. The assessment of these honeycomb structured porous films indicated that not only were these films not cytotoxic but they also enhanced the quantity of cellular proliferation (2.7x) when used as cell culture substrate compared to standard non-porous polystyrene cell culture surfaces. Finally, this research had shown a simple way to generate a new class of highly ordered porous material that could be customized individually for a wide range of applications. The synthesis of amphiphilic block copolymers to generate these films could be achieved by RAFT polymerization with a board selection of polymers choices according to applications. A porous cell substrate such as honeycomb structured porous films could enhance cellular growth when used as a cell culture substrate.

Thesis (Ph. D.)--Ohio University, June, 1987. / Title from PDF t.p.

Thesis (Ph.D.)--McMaster University, 2002. / Advisor: H.D.H. Stöver. Includes bibliographical references. Also available via World Wide Web.