What is Fiber Identification?
The fundamental structure of fabrics is fibers. The identification of fibers is often the first task when an unknown fabric has to be analyzed. The identification of textile fibers is an important component to the textile industry, forensic science, fashion designers, and the automotive industry, among others. The chemical identification of fibers based on the solubility, stain and burning tests is presented. Of course, when testing composition for any fabric, fiber identification is necessary first. There are many methods available for identification of the structural, physical, and chemical properties of fibers. Various methods are used for fiber identification like microscopic methods, solubility, heating and burning method, density and staining etc. End-use property characterization methods often involve use of laboratory techniques which are adapted to simulate actual conditions of average wear on the textile or that can predict performance in end-use. The actual identification, however, varies with industry and method. Changes in textile technology create a constant need to improve identification methodology.
Requirements for Fiber Identification Tests:
- Preparation of test specimen
- Apparatus for microscopic examination
- Reagents used for chemical tests
- Other tools and equipment
Different Methods of Textile Fibers Identification:
- Handle/Feel Test
- Visual Examination
- Burning test
- Twist on Drying
- Floatation Test
- Microscopic analysis
- Chemical Analysis
Basically fiber identification tests are two types; non-technical tests and technical tests.
Non Technical Test:
Non-technical test are three types. They are-
- Feeling test
- Burning test
- Stain test
Above fiber identification tests are described below:
1. Feeling test:
The feeling test requires perception if it is to be of any value. Skilled perception is acquired only after handling many different fabrics over a period of time. Limitations of this test become apparent when examining and comparing fabrics of different fiber content.
2. Burning test:
The burning test is the simplest test for fiber identification. A Bunsen burner is all it needs. However, caution should be exercised in order to avoid confusion caused by fiber blends and fiber finishes. To recognize the composition of fabrics by the burning test, the sample of fiber, yarn of fabric should be moved slowly towards a small flame and the reaction to heat carefully observed. One end of the sample should be put directly into flame to determine its burning rate and characteristics. The burning odor should be noted and the characteristics of the ash such as amount, form, hardness and color should be examined.
3. Stain test:
For uncolored fabrics, staining or dyeing can provide a quick identification of unknown fibers in a sample including the blend samples. DuPont Fabric Dyestain #4 is a common stain widely used in textile testing labs. The unknown sample strip, measuring 2.5 x 10 cm (1 x 4 inches), is boiled with a multifiber standard in a 1% DuPont Fabric Dyestain #4 solution at pH 4.5 at a liquor ratio of 1 : 20 for 10 min.
After rinse and drying, the color of the sample strip is checked against the multifiber standard to identify the unknown fiber. Depending very much on the number of fiber types on the multifiber standard, many commercially available textile fibers can be positively identified.
You may also like: Methods of Identification of New Textile Fibers
Technical Tests
There are certain technical tests performed for identifying various fibers. These tests require high technology laboratory equipment and are much more reliable than the non technical fiber tests. Technical tests require high skilled personnel and technical know how of handling chemicals and their accurate analysis. These tests are very valuable for those fabrics that are a blend of different yarns and also have certain special properties including flame retardant etc.
Types of Technical Test:
- Microscopic test
- Chemical test
a) Microscopic test:
- Microscopic test is a technical test that involves identifying the fabric with the help of a microscope with a magnification of minimum 100 power.
- The test can easily distinguish between fibers.
- The test identifies the natural fibers more easily as compared to man made ones.
- Synthetic fibers are very similar in appearance and the increase in the number of varieties, makes it a little tough to distinguish the fibers even under a microscope.
b) Chemical test:
- Chemical tests are another technical means of identifying fibers. But chemical tests are not intended for the general consumers. Different types of chemical tests are undertaken to establish the identity of the fibers used.
- These tests give accurate and precise analysis.
- The tests are conducted in research laboratory
References:
- Identification of Textile Fibers Edited by Max M. Houck
- Fabric Testing Edited by Jinlian HU
- The Substrates – Fibres, Yarn and Fabric by Mathews Kolanjikombil
- Handbook of Textile Fibre Structure Volume 1: Fundamentals and Manufactured Polymer Fibres Edited by S. J. Eichhorn, J.W.S. Hearle, M. Jaffe and T. Kikutani
Founder & Editor of Textile Learner. He is a Textile Consultant, Blogger & Entrepreneur. He is working as a textile consultant in several local and international companies. He is also a contributor of Wikipedia.
