Abstract Fleece garments are very popular nowadays. This is reflected in forensic fibre cases where fleece garments and especially black colored items are frequently encountered. For this study 201 ...black and dark colored fleece garments were collected from co-workers, friends, family and shops. The constituent fibres were analyzed with common methods used in forensic fibre analyses: microscopy (bright field, polarized light, fluorescence); microspectrophotometry (MSP-visible range); infrared spectroscopy (FTIR) and comparison microscopy. Almost all fleece fabrics were made of 100% polyester fibres. The most abundant fibre type involved polygonal polyester fibres. The appearance of typical fleece-features was explored. It was found that fleece fibres would shed easily, resulting in many long polyester fibres. In many cases these fleece fibres showed typical “mushroom-ends” and in some cases a few thicker fibres that originated from the inner “base layer” of the fleece fabric were also found providing a second fibre type that can be lost from fleece fabrics. Most of the black fleece fabrics could be discriminated with the analytical techniques, the discriminating power DP was found to be 0.9985. This was despite the fact that most of the absorption spectra showed similar features in the visible range. They were denominated as TYPE 1 MSP-spectra and displayed 2 absorption bands at 450 nm and 600 nm.
Abstract One hundred and twenty dyed polyester samples were examined with plane polarized light on their dichroic behaviour by optical light microscopy (OLM) and microspectrophotometry in the visible ...range (MSP Vis). It was found that most of these disperse dyed polyester fibres possess a strong dichroism, which fall into two broad categories. Either a decrease of intensity (hypochromic effect) or a change of hue (hypsochromic or bathochromic shift of absorption bands) is noted. These dichroic effects are related to the orientation of the dye structure with respect to the polymer chains.
The effect of changes in the surface structure of glossy polyester filaments from poly(ethylene terephthalate) in terms of its micro-topography, molecular and supermolecular structure of the fibre ...surface layers on selected fibre surface and volumetric properties has been assessed. The performed tests and measurements have shown that the change in the general surface characteristics of PET fibres (micro-topography and hydrophilicity) results in very beneficial changes in both their volumetric (dyeability) and surface properties (wettability, pilling, oil-soil removal and electric properties).
The paper deals with sensibility of sandy soils shear strength parameters on the size of spread foundation. Minimal, intermediate and maximal values of shear strength parameters of 5 classes of sandy ...soil (SW, SP, S-F, SM and SC) introduced in the old Slovak Technical Standard STN 731001 had been used to design model spread foundation, similar with this one, posted by Orr (2005). The foundation has square shape, thickness 0.8m, founded in the depth D = 1.5m. The foundation is loaded by centrically acting vertical permanent load G = 900kN and variable load Q = 600kN. Underground water level is at foundation base. The spread foundation was designed by design approaches mentioned in Eurocode 7, Part 1 (DA1-C1; DA1-C2; DA2 and DA3) and also by the old and new Slovak Technical Standard STN 73 1001.
Electroless copper plating on polyester fibres was investigated in this work to develop functional textiles. The surface modification of copper plated polyester fibres was characterised by the ...scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction and X-ray photoelectron spectroscope. A possible mechanism of electroless copper plating on polyester was proposed. The results showed that copper particles with high purity were uniformly deposited of polyester fibres and the copper film had a rather perfect crystal structure, demonstrating that electroless deposition was a suitable technique for the uniform deposition of copper.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The effect of extrusion temperature profile in the melt-spinning process of as-spun linear aliphatic-aromatic co-polyester (AAC) fibres upon their mechanical properties and process productivity was ...modelled by using factorial experimental designs. After the viscoelastic and morphology characteristics of the polymer were considered using Differential Scanning Calorimetry and Melt Flow Index (MFI), the rheological data were used to determine the enhanced melt-spinning temperature of the six heating zones in the process. Tensile strength, elongation at break, modulus and fibre productivity (g/min) of the melt-spinning process have been quantitatively assessed as responses to polymer grades and extrusion zone temperature. The optimisation of mechanical properties and productivity helps in understanding and controlling the most desired properties in the produced fibre. It has been noted that the die head temperature (spinning temperature), the polymer grade and their interaction are the most significant factors affecting the mechanical properties. Analysis of the fibre productivity shows that the polymer grade and its interaction with the die head temperature is significant in terms of influencing the output of the melt-spinning process, which could be related to the polymer molecular weight and polymer structure. There is an interaction between polymer grade and feeding zone temperature which is related to the material supply action in the feeding zone. The friction between the screw and the material is affected by heating action, which affects the moisture content and the molten material rheology. By adjusting the extrusion temperature profile and selecting the more applicable spin-able polymer grade through a statistical forecasting model, the combination of the cost related to material grade and processing cost controls the fibre production cost. The fibre made of low MFI grade has better structure and mechanical properties than that made of the higher MFI grade, and the former will be preferred for future work. With previous work related to the effects of extrusion temperature profile on the fibre structure, the present paper will help in developing the production process of biodegradable linear AAC fibres.
One hundred and twenty dyed polyester samples were examined with plane polarized light on their dichroic behaviour by optical light microscopy (OLM) and microspectrophotometry in the visible range ...(MSP Vis). It was found that most of these disperse dyed polyester fibres possess a strong dichroism, which fall into two broad categories. Either a decrease of intensity (hypochromic effect) or a change of hue (hypsochromic or bathochromic shift of absorption bands) is noted. These dichroic effects are related to the orientation of the dye structure with respect to the polymer chains.
Using statistical experimental design, the effects of multi-stage hot drawing process on thermal shrinkage and crystallographic order of linear aliphatic-aromatic co-polyester fibres were ...statistically analyzed. Thermal shrinkage and fullwidth half-maximum (FWHM) of an X-ray scattering profile of the fibres have been quantitatively assessed, and the direction of increasing or decreasing the significant process parameters has been characterized. It has been found that the number of drawing stages, drawing temperature and relaxing stage ratio affect the shrinkage and crystallographic order together. Plate temperature and the interaction between drawing stages and drawing temperature or drawing ratio have an effect on thermal shrinkage; Spin finish application and relaxing temperature have an effect on crystallographic order. The data analysis has been characterized with regard to the relationship between the studied factors statistically analyzed and the scientific reasons suggested. Factorial statistical analysis simulates the combination of drawing process parameters and the selected as-spun environmentally friendly biodegradable fibre.
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