Procedure Of Solubility Test for Fiber Identification | Chemical Test

Solubility Test

Fiber identification is a difficult task but if we know the characteristics of that fiber then it is easy to identify the fiber. Another thing is that, if anyone wants to know the name of an unknown fiber then what can we do? The simple answer is that we can carry out various types of fiber identification tests. Textile fiber can be identified by physical tests, chemical tests, burning tests, density tests, and many more tests.

Here, I like to give a chemical test procedure which is a solubility test. It is a common testing procedure for all types of fiber. I think it will help to identify the fiber.

The procedure of Solubility Test for Fiber Identification:

Followings are the solubility testing procedure:

• Firstly, if we want to carry out the test, we have to maintain the room temperature and place a small sample of the fiber in a watch crystal, test tube, or 50 ml beaker and cover it with test solvent. Here, 1 ml of solvent is necessary for 10 ml of fiber.
• Secondly, if the test performs at the boiling point of the solvent then first bring the solvent to a beaker for boiling on an electric hot plate in a vertical hood.
• Thirdly, the hot plate temperature adjusts to maintain slow boiling and keep watch so that the solvent does not boil dry. Then the fiber sample drops into the boiling solvent.
• After that, if the test carries at some intermediate temperature then a beaker of water is heated on a hot plate. Therefore, adjusts the temperature with a thermometer.
• Then, place the fiber sample in the test solvent in a test tube. After that, immerse it in the heated water bath.
• If the fiber dissolves completely then softens to a plastic mass or remains insoluble.
• Finally, compare the observation data to the standard data to identify the fiber by the solubility test.

Solvents of Different Fiber

The following table shows the different solvents for identifying textile fibers in the solvent test. They are-

Serial Number	Fiber	Solvents Chemicals
01.	Wool and Silk	Sodium hypochlorite (5% chlorine, 25°C)
02.	Silk	Cold 70% Sulphuric acid
03.	Cellulosic Fiber	75% Sulphuric acid (at 25°C)
04.	Viscose	Sodium zincate (cotton insoluble)
05.	Acetate, Triacetate	Glacial acetic acid (at 25°C)
06.	Acetate, Triacetate	Cold acetone
07.	Triacetate (acetate insoluble)	Methylene chloride (at 25°C)
08.	Nylon 6, Nylon 6:6	Hydrochloric acid (1:1Xat 25°C)
09.	Nylon 6, Nylon 6:6	Formic acid (at 25°C)
10.	Acrylic	DMF cold
11.	Nylon 6	DMF at a boil (Nylon 6:6 insoluble)
12.	Acrylic	Ammonium thiocyanate (70% solution at a boil)
13.	Polyester	Meta cresol, 95°C
14.	Polyester	Chloro-phenol (at a boil)
15.	Polypropylene	Meta xylene (at a boil)

So, that’s all about the solubility test. It is a common testing process. I will discuss the solubility testing procedure for individual fiber in my next blog.