Museum textiles provide priceless documentation of the activities of people throughout time. They record human interests and serve as resources for students of many disciplines. In New Zealand there are artefacts made from Phormium tenax which are extremely important in terms of providing a record of early New Zealand life and links to our past as both artistic and cultural symbols: they present an insight into the many faceted nature of early Maori culture. However there are some which are clearly in need of preservative treatment. Others may need care in the future for inevitably they are, or will be, subject to degradation during storage, when on display and during cleaning and refurbishing. Conservators, who embark occasionally on restorative treatments designed to reverse or arrest the symptoms of degradation, have begun to address the causes and future fundamental affects of their procedures. However there have been few scientific studies of the properties of the fibres and, therefore, there is little information to help the conservators in their tasks. This study has a twofold purpose. The first aim is to provide a short survey of the literature on Phormium and relate it to other lignocellulosic fibres. The emphasis in the survey is to put the conservation problem in context and to point to those technical articles which may be relevant to someone dealing with ancient materials. Secondly there is a practical study of the impact of heating the fibres in the absence and presence of oxygen and in water. These two agencies are ones which are directly relevant to the conservator.

The object of this study was to identify microscopic differences among six selected cultivars of harakeke traditionally used by Maori in weaving. The cultivars were Arawa, Makaweroa, Paretaniwha, Takaiapu, Takirikau, and Tapamangu. The effectiveness of different microscopy techniques for taking measurements of the dimensions of ultimate fibres using a factorial experimental design was investigated in part A. Constant variables were geographical location, location of specimens along the leaf, season (winter), individual plant, fan, north-facing fan, and age of plant (approximately seven years), and cultivars (Paretaniwha and Tapamangu). Experimental variables were the microscopy techniques used and measurement axis. Techniques selected use on further cultivars in part B were transverse sections of leaf specimens 4 m thick, embedded in Paraplast� and observed using LM, and non-fixed ultimate fibres observed using SEM. In part B the dimensions of ultimate fibres from the six selected cultivars of harakeke were measured, and analysed (ANOVA and Tukey's HSD), and the transverse section shapes of fibre aggregates were observed. Transverse widths of ultimate fibres ranged from 10.15 m (Takaipu) -12.80 m (Paretaniwha). Ultimate fibre lengths ranged from 3735 m (Takirikau) - 4751 m (Makaweroa). The cultivars prizes for muka, Arawa and Makaweroa, had the longest and finest ultimate fibre bundles more uniform in transverse-sectional shape than the other cultivars studied and perhaps this explains their selection for extraction of muka. Takirikau had a high yield of ultimate fibre bundles, and perhaps this makes extraction of muka worthwhile. Paretaniwha differed from the other five cultivars studied having an average number of ultimate fibre bundles per unit width that were narrow and non-uniform in shape, and composed of short, thick, ultimate fibre cells. The microscopic structure of muka from six selected cultivars of harakeke used traditionally for weaving varied and may explain differences perceived by weavers, and that different end uses are preferred for various cultivars.

The object of this study was to identify microscopic differences among six selected cultivars of harakeke traditionally used by Maori in weaving. The cultivars were Arawa, Makaweroa, Paretaniwha, Takaiapu, Takirikau, and Tapamangu. The effectiveness of different microscopy techniques for taking measurements of the dimensions of ultimate fibres using a factorial experimental design was investigated in part A. Constant variables were geographical location, location of specimens along the leaf, season (winter), individual plant, fan, north-facing fan, and age of plant (approximately seven years), and cultivars (Paretaniwha and Tapamangu). Experimental variables were the microscopy techniques used and measurement axis. Techniques selected use on further cultivars in part B were transverse sections of leaf specimens 4 m thick, embedded in Paraplast� and observed using LM, and non-fixed ultimate fibres observed using SEM. In part B the dimensions of ultimate fibres from the six selected cultivars of harakeke were measured, and analysed (ANOVA and Tukey's HSD), and the transverse section shapes of fibre aggregates were observed. Transverse widths of ultimate fibres ranged from 10.15 m (Takaipu) -12.80 m (Paretaniwha). Ultimate fibre lengths ranged from 3735 m (Takirikau) - 4751 m (Makaweroa). The cultivars prizes for muka, Arawa and Makaweroa, had the longest and finest ultimate fibre bundles more uniform in transverse-sectional shape than the other cultivars studied and perhaps this explains their selection for extraction of muka. Takirikau had a high yield of ultimate fibre bundles, and perhaps this makes extraction of muka worthwhile. Paretaniwha differed from the other five cultivars studied having an average number of ultimate fibre bundles per unit width that were narrow and non-uniform in shape, and composed of short, thick, ultimate fibre cells. The microscopic structure of muka from six selected cultivars of harakeke used traditionally for weaving varied and may explain differences perceived by weavers, and that different end uses are preferred for various cultivars.

It has been observed that in certain cases the exposure of dyed fibres to aging techniques results in the strengthening of fibres. This thesis explores the hypothesis that the strengthening is due to radical cross-coupling reactions that could be initiated through metal ion mediated photodecarboxylation. The approaches taken in this research include kinetic experiments (using flash photolysis), examination of possible cross-coupling experiments (using species of opposite charge), and the design and examination of small molecule model systems. A flash photolysis system was developed and used in attempts to determine the rates of photochemical product formation for cobalt(III) amino acid complexes. Lower limits have been established for the rate of product formation in these systems. The lower limits are: 2 x 10⁷ s⁻¹ for [Co(bpy)2(gly)]²⁺; 2 x 10⁷ s⁻¹ for [Co(tpa)(gly)]²⁺; and 5 x 10⁶ s⁻¹ for [Co(tpa)(aib)]²⁺, where bpy is 2,2'-bipyridine; gly is glycinate; tpa is tris(2-pyridylmethyl)amine; and aib is aminoisobutyrate. In past studies, the rates of a series of cobalt(III) amino acid complexes were reported as being the same, and much slower. It is thought that in these cases it may not be the rate of the formation of product that was being measured, but rather the response time of the electronics that was being observed. In this thesis the results obtained for the rate for the aib complex were somewhat lower than those of the gly complexes. This may imply, for the aib complex at least, the rate of the formation of the metallocycle is being observed (and not the response times of the electronics or other limitations of the instrumentation), but the data is poor and there is considerable doubt about this. The steady state photolysis of opposite charged species [Co(bpy)2(gly)]²⁺ and [Co(EDTA)]⁻ is reported. The reactions were carried out on a small scale in deuterated solvent for NMR spectrometry analysis and also on a large scale for the possible isolation and characterisation of the products. Evidence was found for a different reaction occurring when both complexes were present. The exact nature of the product remains elusive. A model system was designed in which a dinuclear ligand would bind to two metal centres and a fibre mimic would be later added. Eight ligands are discussed that could potentially bind two octahedral metal centres. They all had a xylene spacing group linking the two polydentate sites together. Five of the ligands have two bidentate binding sites. The other three had two tridentate sites. The binding sites in three of the bis(bidentate) ligands were based on ethane-1,2- diamine (en). Two of these ligands produced hypodentate monocobalt and sundentate dicobalt complexes. The other two bidentate ligands were based on 2- aminomethylpyridine (ampy). Both of these ligands degraded in the complexation reaction conditions. The binding sites in the tridentate ligands were all based on tacn. Once again, the principal products isolated were hypodentate systems in which only one metal ion was coordinated by the ligands. There is a distinct pattern observed in the xylene spaced ligands to form hypodentate complexes with cobalt(III) metal centred complexes. There is evidence of the di-nuclear species from a reaction with a charcoal catalyst in the bis(bidentate) system. ¹H NMR spectrometry, ¹³C NMR spectrometry, elemental analysis, X-ray crystallography and UV-vis spectroscopy were used to study and characterise the complexes and ligands that were prepared in this project.

It has been observed that in certain cases the exposure of dyed fibres to aging techniques results in the strengthening of fibres. This thesis explores the hypothesis that the strengthening is due to radical cross-coupling reactions that could be initiated through metal ion mediated photodecarboxylation. The approaches taken in this research include kinetic experiments (using flash photolysis), examination of possible cross-coupling experiments (using species of opposite charge), and the design and examination of small molecule model systems. A flash photolysis system was developed and used in attempts to determine the rates of photochemical product formation for cobalt(III) amino acid complexes. Lower limits have been established for the rate of product formation in these systems. The lower limits are: 2 x 10⁷ s⁻¹ for [Co(bpy)2(gly)]²⁺; 2 x 10⁷ s⁻¹ for [Co(tpa)(gly)]²⁺; and 5 x 10⁶ s⁻¹ for [Co(tpa)(aib)]²⁺, where bpy is 2,2'-bipyridine; gly is glycinate; tpa is tris(2-pyridylmethyl)amine; and aib is aminoisobutyrate. In past studies, the rates of a series of cobalt(III) amino acid complexes were reported as being the same, and much slower. It is thought that in these cases it may not be the rate of the formation of product that was being measured, but rather the response time of the electronics that was being observed. In this thesis the results obtained for the rate for the aib complex were somewhat lower than those of the gly complexes. This may imply, for the aib complex at least, the rate of the formation of the metallocycle is being observed (and not the response times of the electronics or other limitations of the instrumentation), but the data is poor and there is considerable doubt about this. The steady state photolysis of opposite charged species [Co(bpy)2(gly)]²⁺ and [Co(EDTA)]⁻ is reported. The reactions were carried out on a small scale in deuterated solvent for NMR spectrometry analysis and also on a large scale for the possible isolation and characterisation of the products. Evidence was found for a different reaction occurring when both complexes were present. The exact nature of the product remains elusive. A model system was designed in which a dinuclear ligand would bind to two metal centres and a fibre mimic would be later added. Eight ligands are discussed that could potentially bind two octahedral metal centres. They all had a xylene spacing group linking the two polydentate sites together. Five of the ligands have two bidentate binding sites. The other three had two tridentate sites. The binding sites in three of the bis(bidentate) ligands were based on ethane-1,2- diamine (en). Two of these ligands produced hypodentate monocobalt and sundentate dicobalt complexes. The other two bidentate ligands were based on 2- aminomethylpyridine (ampy). Both of these ligands degraded in the complexation reaction conditions. The binding sites in the tridentate ligands were all based on tacn. Once again, the principal products isolated were hypodentate systems in which only one metal ion was coordinated by the ligands. There is a distinct pattern observed in the xylene spaced ligands to form hypodentate complexes with cobalt(III) metal centred complexes. There is evidence of the di-nuclear species from a reaction with a charcoal catalyst in the bis(bidentate) system. ¹H NMR spectrometry, ¹³C NMR spectrometry, elemental analysis, X-ray crystallography and UV-vis spectroscopy were used to study and characterise the complexes and ligands that were prepared in this project.