Videotutorial Fiber Analysis
In this video you will learn how the fibre type of textile fabrics, yarns or individual fibres can be determined by analysing the fibres through surface observation, melting point determination or observation of the reaction behaviour with reagents. Different methods can be applied for fibre identification. Amongst other things, fibre identification is necessary for textile labelling, which is prescribed by law; as well as for textile export. However, it is primarily relevant for quality control within a company.
Microscopic fibre identification is used to determine whether the fibres present have actually been used for the textile or whether, for example, higher quality fibres have been eked out with cheaper fibres. It can also identify whether foreign fibres are present which have not been mentioned but which must be listed as per Textile Labelling Directive. It can also prove whether there is contamination from other fibres. Fibre identification can make sure that the quality of the textile has been correctly labelled within the framework of the European Textile Labelling Directive. If there is a label, it is checked to determine whether this is correct using the specified components and whether the percentage distribution is correct.
In the method shown, fibres are identified by means of an enlarged longitudinal view using characteristic visual features or type reactions. Microscopic fibre identification takes place as part of textile testing. The chemical separation then takes place in the laboratory. A small material sample is sufficient for identification. For unique identification, it may be necessary to perform solution attempts using different reagents and observe different behaviours of the fibres.
The longitudinal view of the fibres is examined under the microscope. The longitudinal view of cotton fibres exhibits irregular twists when embedded in distilled water. It is more or less strongly twisted and has isolated thickenings. When embedded in diluted sodium hydroxide, the fibres swell, lose their twists and, if they are good condition, exhibit a mushroom-like bulge at the ends.
The longitudinal view of polyester fibres is unstructured and smooth, as for most synthetic fibres. The longitudinal view on its own does not give any indication of the type of synthetic fibre. If the polyester fibres are heated with alcoholic potash, crystals form on the fibres. This is a clear indication of the presence of polyester.