Composite materials based on natural bast fibres offer potential commercial and environmental benefits due to the low cost, availiability, and biodegradability of the fibres. However, such benefits cannot be realised without a comprehensive evaluation of processing and properties. This thesis involved a comprehensive evaluation of composites based on two types of natural bast fibre (hemp and flax), and two types of matrix - synthetic (epoxy), and biodegradable (Novamont Mater-Si). The experimental work involved four strands: the effects of growing conditions and fibre processing on the properties of raw bast fibres; the optimisation of a pultrusion process for epoxy-matrix composites; development of a film stacking process for Mater-Bi composites, and a detailed evaluation of the mechanical properties of the composites themselves. Fibre bundles and individual fibre cells were investigated to characterise their structure, with particular focus on compressive kink defects. The kink bands were sectioned using a novel technique of focused ion beam milling, and kinking was found to induce delamination and voiding of the lamellar fibre structure. The defect concentration per unit length was assessed for conventionally-processed fibres and for hemp fibres from plants grown under controlled conditions to assess the effect of wind shear and stem flexure on fibre defect concentration. No effect was found for plant flexure, while industrially processed fibre was found to have increased defect concentration. The loading behaviour of both types of composite was seen to be initially linear with a yield point at 20 - 30 MPa and a transition to nonlinear deformation dominated by damage mechanisms as a result of fibre kinks. Epoxy composites possessed an inital modulus of 30 GPa with a 30 - 60% reduction in modulus after yield. Flax reinforcement was found to increase the modulus of Mater-Bi from 0.1 to 20 GPa and strength from 24 to 169 MPa. Fibre addition was also found to significantly embrittle the polymers.

The dimensions of airborne fibres collected at various stages of fibre processing in mines and mills producing crocidolite, amosite and chrysotile asbestos were measured by using light optical and electron microscopy. Airborne fibres of different asbestos types had markedly different size and shape distributions. For a given asbestos type, airborne fibres collected at various stages of processing differed in their size distributions but the differences were considerably less than between fibre types. Most of the airborne fibres to which miners and millers were exposed were short, thin and thus respirable. The proportions of long fibres in the air of crocidolite and chrysotile mines and mills were small compared to those in amosite mining and milling environments. The physical parameters which best differentiated crocidolite fibres from other asbestos fibre types were aspect ratio, which was higher, and proportions of long thin fibres (0.06 - 0.2 (mu)m in diameter and > 5 (mu)m in length). Median mass of amosite fibres was more than 108 and 13 times higher than the median mass of chrysotile and crocidolite fibres respectively. Median true diameter of amosite fibres was approximately 4 and 3 times higher than median true diameters of chrysotile and crocidolite fibres respectively. Median true length of amosite fibres was more than 4.5 and 1.9 times higher than median true lengths of chrysotile and crocidolite fibres respectively. / The differences in size and shape of airborne fibres have important implications for setting of work environmental standards and explaining differences in health risks associated with different fibre types.

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The purpose of this investigation was to determine the properties that characterise cotton fibres in the various stages in the CPNF process as well as to determine which fibre characteristics a r e required to entangle the fibres to produce a successful CPNF . The criteria adopted in this work for a successful CPNF include: 1. the tensile strength of the fabrics 2. a well-defined pattern 3. absorbency and wicking The properties selected for investigation were 1. the cotton fibre surface (using SEM and DSC analyses) 2. the degree of degradation of the cotton fibre as a result of the CPNF process (using cellulose fluidity measurements) 3. the non-cellulosic content of the fibre (using IR, DSC, and Chemical analyses) 4. fibre friction 5. absorbency and wicking 6. tensile properties Analysis of the results indicates clearly what the fundamental properties of the cotton fibre must be for a successful cotton CPNF to be manufactured. The conclusions also indicate the necessary properties a man-made fibre must have to produce a successful CPNF.

A new technique for measuring the water content of fiber is presented. Tritiated water is added to a pulp/water suspension whereupon the tritium partitions between the bulk water and the pulp. Through this technique a fiber:water partition coefficient is developed, Kpw. This thesis will cover the development of the Kpw procedure and three different case studies. The first study involves comparing Kpw to traditional methods of fiber water content. The procedure provides a value of ten percent for the tightly bound water content of unrefined hardwood or softwood kraft fiber, either bleached or unbleached. If this water is assumed to cover the fiber surface as a monolayer, then an estimate of the wet surface area of fiber can be obtained. This estimate compares well to independent measurements of surface area. Kpw has also been found to be valuable in furthering the understanding of refining. Based on the study, it is proposed that refining occurs in three discrete stages. First, refining removes the primary cell wall and S1 layer while beginning to swell the S2 layer. Next, internal delamination occurs within the S2 layer. Finally, fiber destruction occurs at high refining levels. By using Kpw, the three stages of refining are clearly recognized. Lastly, Kpw is used to study the effect of hornification on bleached softwood kraft fiber. The recycling effects at three refining levels were characterized by Kpw and followed closely the findings of the refining study. At low and high refining levels, the impact of recycling was minimal according to Kpw results, but at 400 mL csf the impact of recycling was much more pronounced. This could be attributed to the closing of internal delaminations within the fiber.

[Truncated abstract] Palynology has been used in a number of criminal cases where pollen and spores (palynomorphs) on clothing has featured as evidence. Pollen and spores are microscopic, generally morphologically unique to a plant genus and often species, resistant to decay, produced in large amounts and are components of soil. These unique features of pollen and spores make palynology a highly valuable forensic tool. Clothing is an excellent collector of pollen and spores as they become trapped in the fabric weave when clothing is brushed against flowering plants, comes into contact with dust, soil or air-borne pollen. Most forensic palynologists have found that palynomorphs from a crime scene may remain on clothing after washing or several days wear. No empirical research has been conducted on the retention of palynomorphs on clothing under differing conditions. Research of this kind is required to provide support for the future presentation and validation of palynological evidence in court. This project examined the relative retention of palynomorphs on clothing that had been worn during a simulated assault in a sheltered garden on the grounds of St George's College, Western Australia. Three replicate control soil samples each were collected from the actual assault scene and the whole garden to provide a baseline palynological profile for comparison to the experimental (Evidentiary) clothing samples. Forty pollen samples from the predominant species of plants in the garden and surrounds were collected, processed and databased as a reference for palynomorph identification. Standard T-shirts and jeans were chosen as the research clothing. During the simulated assault the knees of the jeans and the backs of the T-shirts came into abrasive contact with the soil of the garden for approximately one minute. The clothing then underwent three 'conditions' to simulate 'real life' situations. Three clothing sets were immediately collected after the assault (E1), three sets were worn for a period of three days after the assault (E2) and three sets were washed after the assault (E3). ... The Background clothing samples did not have a profile similar to the research garden but the profiles collected from each set reflected the areas to which they were worn. The number of palynomorphs per gram of garden soil ranged from thousands to tens-of-thousands of palynomorphs. The total number of palynomorphs collected by the E1 samples ranged from 100,000 to millions per clothing item. The E2 samples retained 1000's to tens-of-thousands of palynomorphs and the E3 samples retained 100's to 1000's of palynomorphs. The background clothing samples collected 1000's to tens-of-thousands of palynomorphs. These results confirm that jeans and T-shirts worn during an assault then worn for a period of days, or washed, will still contain pollen and spores characteristic of the assault area. This highlights the importance of investigating police enquiring where and for how long clothing of interest has been worn before and after an event, or if the clothing has been washed since the event. The results of this study will provide forensic palynologists with supportive data for future casework involving clothing.

Indiana University-Purdue University Indianapolis (IUPUI) / Microspectrophotometry is a quick, accurate, and reproducible method to compare colored fibers for forensic purposes. The use of chemometric techniques applied to spectroscopic data can provide valuable discriminatory information especially when looking at a complex dataset. Differentiating a group of samples by employing chemometric analysis increases the evidential value of fiber comparisons by decreasing the probability of false association. The aims of this research were to (1) evaluate the chemometric procedure on a data set consisting of blue acrylic fibers and (2) accurately discriminate between yellow polyester fibers with the same dye composition but different dye loadings along with introducing a multivariate calibration approach to determine the dye concentration of fibers. In the first study, background subtracted and normalized visible spectra from eleven blue acrylic exemplars dyed with varying compositions of dyes were discriminated from one another using agglomerative hierarchical clustering (AHC), principal component analysis (PCA), and discriminant analysis (DA). AHC and PCA results agreed showing similar spectra clustering close to one another. DA analysis indicated a total classification accuracy of approximately 93% with only two of the eleven exemplars confused with one another. This was expected because two exemplars consisted of the same dye compositions. An external validation of the data set was performed and showed consistent results, which validated the model produced from the training set. In the second study, background subtracted and normalized visible spectra from ten yellow polyester exemplars dyed with different concentrations of the same dye ranging from 0.1-3.5% (w/w), were analyzed by the same techniques. Three classes of fibers with a classification accuracy of approximately 96% were found representing low, medium, and high dye loadings. Exemplars with similar dye loadings were able to be readily discriminated in some cases based on a classification accuracy of 90% or higher and a receiver operating characteristic area under the curve score of 0.9 or greater. Calibration curves based upon a proximity matrix of dye loadings between 0.1-0.75% (w/w) were developed that provided better accuracy and precision to that of a traditional approach.

The novel instrumentation of nanomanipulation coupled to nanospray mass spectrometry and its applications are presented. The nanomanipulator has the resolution of 10nm step sizes allowing for specific fine movement used to probe and characterize objects of interest. Nanospray mass spectrometry only needs a minimum sample volume of 300nl and a minimum sample size of 300attograms to analyze an analyte making it the ideal instrument to couple to nanomanipulation. The nanomanipulator is mounted to an inverted microscope and consists of 4 nano-positioners; these nano-positioners hold end-effectors and other tools used for manipulation. This original coupling has been used to enhance the current abilities of cellular probing and trace fiber analysis. Experiments have been performed to demonstrate the functionality of this instrument and its capabilities. Histidine and caffeine have been sampled directly from single fibers and analyzed. Lipid bodies from cotton seeds have been sampled indirectly and analyzed. The few applications demonstrated are only the beginning of nanomanipulation coupled to nanospray mass spectrometry and the possible applications are numerous especially with the ability to design and fabricate new end-effectors with unique abilities. Future study will be done to further the applications in direct cellular probing including toxicology studies and organelle analysis of single cells. Further studies will be directed in forensic applications of this instrument including gunshot residue sampled from fibers.

The National Academy of Sciences recently published a report which calls for improvements to the field of forensic science. Their report criticized many forensic disciplines for failure to establish rigorously-tested methods of comparison, and encouraged more research in these areas to establish limitations and assess error rates. This study applies chemometric and statistical methods to current and developing analytical techniques in fiber analysis. In addition to analysis of commercially available dyed textile fibers, two pairs of dyes are selected based for custom fabric dyeing on the similarities of their absorbance spectra and dye molecular structures. Visible absorption spectra for all fiber samples are collected using microspectrophotometry (MSP) and mass spectra are collected using electrospray ionization (ESI) mass spectrometry. Statistical calculations are performed using commercial software packages and software written in-house. Levels of Type I and Type II error are examined for fiber discrimination based on hypothesis testing of visible absorbance spectra using a nonparametric permutation method. This work also explores evaluation of known and questioned fiber populations based on an assessment of p-value distributions from questioned-known fiber comparisons with those of known fiber self-comparisons. Results from the hypothesis testing are compared with principal components analysis (PCA) and discriminant analysis (DA) of visible absorption spectra, as well as PCA and DA of ESI mass spectra. The sensitivity of a statistical approach will also be discussed in terms of how instrumental parameters and sampling methods may influence error rates.