The stain test is another chemical test for the fiber identification process. Besides, I have already written about the solubility test which is a chemical testing method. This type of test shows the natural shades of the fiber. All the fibers do have not the same natural color and it can find out by treating the fibers with a drop of zinc chloro-iodide reagent.
Procedure Of Stain Test To identify The Textile fibers:
- At first, different natural fibers are taken for the test.
- A few fibers are placed on the microscopical slide.
- A drop of zinc chloro-iodide reagent is applied to the fiber and covered with a coverslip taking care to avoid bubbles.
- Examine the fibers for staining.
- By the observation, we will find the following results-
- Hemp, Ramie, and cotton stain violet.
- Flax stain brownish violet.
- Jute stain brown.
- Many other fibers stain shades of yellow-brown including silk.
- Warm a few fresh fibers on a microscopical slide with a drop of acid Phloroglucinol reagent.
- Woody fibers such as unbleached jute stain deep magenta because of the presence of Lignin.
So, after observing the test sample we can decide about the fiber. It is the most common process to know the natural shade of the fiber. Also, we can carry out density tests, drying twist tests, and others to identify the fibers.
Textile fibers play an important role in the apparel or clothing industry. Besides, different textile fiber has a various chemical composition and differ in their physical and chemical properties. The color of the fiber also depends on the growing country and the soil where it grows or the region from where it collects.
Finally, it needs to perform a stain test to be sure about the color of the fiber.