Textiles, sample preparation methods

Corrections of the apparent crystallinity values of fibers materials have been carried out by taking into account a disorder parameter k, following Ruland s method. Peculiar care was taken about samples preparation (cutting and pelleting of fibers), data collection and reduction, which will be briefly described. Crystallinity and disorder parameter measurements have been performed on main textile fibers (polyester, polyamide, aramid, polypropylene, cellulosic fibers) and the results will be discussed comparatively, with those got by more conventional x-ray crystallinity determinations. The complementarities of these different approaches will be illustrated with several examples. For instance,... 

IR spectroscopy is a common analytical technique in the textile industry. IR is capable of identifying fibers and their additives, as well as showing quantitative blend ratios and additive contents. The ATR (attenuated total reflection) technique, especially in its multiple form, MIR (multiple internal reflection) is of special importance in this field. The sample preparation is simple and fast the cut out swatches with appropriate surface areas are placed against each side of the MIR crystal, ensuring sufficient and uniform contact across the crystal surface. The internal reflection methods are non-destructive, so that the sample may be saved for other types of analysis, they are, further, methods of surface analysis. This is advantageous in all cases where the finish resides primarily on the fiber surface. In this case, a very strong spectrum of the finish is obtained, with minimal interference from the base fiber (Hannah et al., 1975). 

Near infrared (NIR) spectroscopy has been a useful analytical technique employed for many years in the pharmaceutical, cosmetic and textile industries. Its utility has been enhanced by the addition of multivariate calibration techniques. In addition, the ease of sample preparation and speed of analysis make NIR ideal for use as a quality control method. 

Book topics include practical aspects of spectrometers and spectrometry, sample preparation, chemometrics, and calibration practices reflectance measurements and standard materials measurements. We have placed an emphasis on reflectance and color measurements due to their common usage in today s spectroscopic laboratories. Methods for selecting a measurement technique are included, as well as solar and color measurements. Spectrometry of new materials, ceramics, and textiles are covered by respective experts in their fields. An appendix of practical reference data for UV-VIS, NIR, IR bench top, IR microspectroscopy, and UV Sun Protection Factor (SPF) measurements is included. 

Sample preparation is a critical step in thermal characterization of fibers. Samples of textile cloth, yam or fiber are often studied by cutting the material into small pieces to facilitate their transfer to a small-volume cmcible and establish a reproducible and efficient thermal contact with the interior surface of the cmcible. The results shown in Fig. 10.1 (Steinmann et al., 2013) illustrate the importance of optimization of sample preparation. In this case significant differences arise from the use of clippings (or stripes), knots and bundles and from the choice of cmcible volume. A clear advantage is observed in clipped fiber samples where this method of sample preparation permits... 

The statistical analysis method of discriminant analysis [342] has been combined with NIRA to identify dissimilar textile products. Most textile fibres, yarns, and fabrics have chemical structures which yield complex NIR spectra, and as such these species normally require three or more wavelengths to classify the material. Discriminant analysis is simple to use, rapid, and does not require extensive, time-consuming sample preparation and analysis. Polyester staple fibres of different tenacity levels have different fabric dyeing properties. NIRA method with discriminant analysis successfully identifies and classifies the polyester staple samples by tenacity level and thus provides a quick technique for identification of polyester fibre anticipating quality problems [315]. Mitchell et al [343]... 

Many of the fabric structures from which these samples were taken have been described in other publications (1-3). In experimenting with appropriate methods for preparation of samples for elemental analysis, fibers are of limited value because they cannot be proven to belong to the textile object in the box. For experimental purposes, these fabrics served well as representative brittle, fragile, and minute fibrous samples for preparation and analysis. 

For the separation and determination of inorganics in some biological samples (115,180), textile materials (118), environmental water samples (55,81,129,204,206), plants and food stuffs (112,206), alloys (51,84,128,182,207), and geological samples (89,94,127,207), specific standard methods are followed. Relatively pure real samples or their concentrated extracts can be spotted directly for TLC analysis. However, if the analyte concentration in a complex sample (biological, plant, environmental, food etc.) is low, extraction of the analyte from the sample matrix, cleanup of the extract and concentration of the analyte usually precede TLC. Below are given some examples for the preparation of solutions of real samples ... 

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