Textile microscopic analysis

The textile pieces in the Brantley collection were subjected to historical research and microscopic analysis. These were done to verify the information already existing on the collection, to identify those fragments for which information was missing, to classify the fragments as textiles, and to identify the metallic threads that were part of the textiles. 

Microscopical methods are used in the textile industry to investigate raw materials, for product development and analysis of competitor s samples, and to check production and control effects and quality. Typical examples of their use are shown in Table 8.2. Textile microscopy is indispensable in dealing with complaints and analysing damage as well as in avoiding faults and repudiating unjustified claims. Microscopy is, of course, just as important in textile research (for example in the analysis of the fine structure of fibres, surface modifications and investigations on the distribution of dyes and auxiliaries). 

Imprint techniques have been a proven and important method in damage analysis of textiles for a long period of time. It is often advantageous not to investigate the original object under the microscope but rather the negative imprint of its surface ... 

Microscopic examination All fibers have distinguishing features that allow either outright identification or classification into a narrower grouping for specialized analysis. Animal hair fibers, for example, have a characteristic scaled surface. In addition, many textile yarns are blends of two or more fiber types. A simple examination with a normal light microscope can establish this and allow the components of the yam to be separated for more detailed evaluation. The major identifying characteristics are ... 

DRIFT spectroscopy of microscopic amounts of dye mixtures extracted from small textile samples has been reported raw and pretreated data matrices were interpreted with the use of chemomet-rics (PCA, SIMCA, FC) [145]. DRIFTS can readily detect 200 ng quantities of pure, standard dyes. Bridge et al. [42] have qualitatively characterised acid dyes (Cl Acid Red 17, Red 18, Red 44, Red 88, Blue 45 and Yellow 17) applied to wool and nylon. Near-infrared diffuse reflectance spectroscopy was evaluated for its ability to analyse solid antioxidant blends [146]. These opaque materials do not transmit near-IR light. This fast method effectively predicts weight percentage composition with a precision comparable to the currently accepted HPLC method of analysis, and can identify blend types and contaminated materials. 

Recent studies of micro ATR have defined the best experimental conditions for establishing optical contact between the ATR crystal and the sample [25]. This experimental approach has been applied to the analysis of the failure surfaces of adhesively bonded joints. ATR-microscopic measurements have been used for direct measurement and identification of raw materials in textiles coated and impregnated substances on paper [26]. An ATR microscopic probe has been developed which allows one to examine the sample optically through the probe in the microscope. The hemispheric ATR crystal is mounted at the focus of the Cassegrain objective, below the secondary mirror. One can position the crystal in contact with the sample, and run the spectra [27]. In the survey mode, visible light at nearly normal incidence is selected to locate the area of measurement. In the contact mode, low incident angle visible is used to detect contact of the sample to the ATR crystal surface. In the measurement mode, the ATR crystal is slid into position and the incident beam is optimized for total internal reflection. In the Spectra Tech version, all of the available crystals, i.e. ZnSe, Diamond, Silicon, and Germanium can be used. However, Ge and Si are opaque and cannot be used in the survey or contact mode. An optical contact sensor can be used. 

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