FIBER RECOGNITION IN HOME CONDITIONS
This section describes the methods of identifying the fibers most commonly found in textiles, the identification methods have been compiled with a view to the possibility of using them at home. However, you should be aware, that the textile industry uses raw material mixtures for the production of a wide range of products and that the identification of such products at home is difficult or even impossible. Products from single-component raw materials, which can be identified with high probability by simple methods, they mainly contain the so-called. continuous filaments. Determining this fact is quite simple (see p. 1). Raw material mixtures are generally found in products made of staple fibers. In this case, home-made identification goes towards finding, that there is no fiber in the mixture that is particularly sensitive to the specific stain removal procedure (this is usually the case with acetate and polyvinylchloride fibers, e.g.. Care).
Methods of research
1. Yarn testing "against the light"
This test determines whether the yarn is made of filaments, or cut. The presence of fibrils protruding along the axis of the yarn indicates the presence of staple fibers. The yarn when folded several times slightly taut on the finger shows a shine, when it is made of continuous filaments.
2. Yarn tearing
2.1. Wet yarn tearing. This test makes it possible to distinguish man-made cellulose fibers (e.g.. viscose) from cotton. The yarn is well moistened with water halfway along a certain length and then stretched until broken. In the case of cotton, the break will be in the dry place of the yarn; a rupture in a wet area indicates the presence of viscose fibers.
2.2. Yarn tearing "dry". This method is used to distinguish cotton fibers from flax fibers. The yarn stretch is stretched to break and the ends are observed. In the case of flax fibers, the ends form a fairly long stiff "mustache", under these conditions cotton forms a tight strand.
3. Trying to smoke
A properly conducted smoking test helps to distinguish between the various groups of textile raw materials, how: cellulose fibers (Cotton, len, viscose and others), protein (wool, natural silk, Wipolan), synthetic fibers (e.g.. polyamide, polyester, poliakrylonitrylowe i in.). This test is particularly suitable for identifying spontaneously occurring textile raw materials (not in mixtures). The test is performed as follows: a length of yarn that has been folded several times is placed for a moment in as little flame as possible, holding the yarn perpendicular to the flame, then it is taken out and fixed:
3.1. How quickly the yarn burns. Rapid burning indicates the presence of cellulose fibers.
3.2. The nature of ash. Stands out:
- "fly" ash, it is that, which disintegrates after blowing - occurs with cellulose fibers;
- ash with a granular consistency (slag), crushable in fingers - occurs with protein fibers;
- a residue in the form of a hard toplin, not crushed in fingers - occurs with synthetic fibers.
3.3. Smell. The well-known smell of burnt paper and the smell of burnt hair can be clearly distinguished here. The first indicates the presence of cellulose fibers, the second - protein fibers (the most common wool, but also natural silk). The results of the smoking tests are shown in the table below.
4. Chemical action
The yarn, taut in the fingers, is treated with a drop of a reagent. Yarn breakage or weakening indicates the presence of certain types of fibers. On the page 116 gives a way of identifying fibers that can be used by individual users of textile products, who have the most available and popular reagents in the household, like acetone and formic acid. The determination of the solubility of the fibers in acetone allows the presence of acetate and polyvinylchloride fibers to be determined, thus the fibers most sensitive to agents used to remove stains in textiles. The solubility of the fibers in formic acid along with the negative effect of acetone indicates the presence of polyamide fibers.
|*) Polyester fibers can be distinguished from polyacrylonitrile fibers by attempting to dissolve in dimethylformamide (DMF) at elevated temperature (ok. 55°C). Under these conditions, polyacrylonitrile fibers dissolve.|