Microscopic and Chemical Test of Textile Fibers

Last Updated on 16/11/2022

Testing of Textile Fibers:
Testing is done primarily to test the quality and there are different ways to carry out a test. 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 retardance etc. In this article I will discuss microscopic and chemical test of textile fibers.

microscopic test of textile fibers
Fig: Microscopic test of textile fibers

Various national and international organizations have established standards for textile testing. ISO, AATCC, ASTM are important organizations for testing textile.

Types of Technical Test:

  1. Microscopic test
  2. Chemical test

Microscopic Test of Textile Fibers:

  1. Microscopic test is a technical test that involves identifying the fabric with the help of a microscope with a magnification of minimum 100 power.
  2. The test can easily distinguish between fibers.
  3. The test identifies the natural fibers more easily as compared to manmade ones.
  4. 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.

Microscopic Test for Natural Fibers:


  • It is a single elongated cell. Under the microscope, it resembles a collapsed, spirally twisted tube with a rough surface.
  • The thin cell wall of the fiber has from 200 to 400 convolutions per inch.


  • Under the microscope, the hair like flax fiber shows several sided cylindrical filaments with fine pointed ends.
  • The fiber somewhat resembles a straight, smooth.


  • Under the microscope, wool’s cross section shows three layers-epidermis, cortex and the medulla.


  • It appears somewhat elliptical and triangular in cross section when we see under the microscope.
  • It is composed of fibroin, consisting of two filaments, called brin which is held together by sericin.

Microscopic Test for Manmade Fibers:


  • Rayon fibers have a glass like luster under the microscope and appear to have a uniform diameter when viewed longitudinally.


  • The cross sectional view has a bulbous or multilobal appearance with indentations.
  • These indentations appear as occasional markings.


  • The basic microscopic appearance is generally fine, round, smooth, and translucent.
  • It is also produced in multi-lobal cross-sectional types.


  • Generally, polyester fibers are smooth and straight and the cross-section is round.
    This general characteristics may be altered to achieve certain characteristics.

The methods of manufacturing of the acrylic fibers differ, the appearances vary accordingly.

  1. Acrilan Acrylic: It has a bean-shaped cross section, its longitudinal appearance is straight and smooth.
  2. Orlon Acrylic: It has a flat, nut-shaped cross section.
  3. Creslan Acrylic: It has an almost round cross section.
  4. Mod Acrylics: it is of two types verel modacrylic and SEF modacrylic


  • Spandex fibers are unique in appearance; they appear to be groups of fibers fused together.

Glass Fiber:

  • The fiber is smooth, round, translucent, highly lustrous, and quite flexible.

Chemical Tests of Textile Fibers:

  1. Chemical tests are another technical means of identifying fibers. But chemical tests are not intended for the general consumers.
  2. Different types of chemical tests are undertaken to establish the identity of the fibers used.
  3. These tests give accurate and precise analysis.
  4. The tests are conducted in research laboratories.

Types of chemical test:

Stain Test:
Also known as the Double Barrel Fiber Identification (DBFI), the test is based on the theory that each fiber has its own distinct two-color reaction when treated with stain.

A fiber will turn to a particular color in the presence of dilute acetic acid and to some other specific color when stained in the presence of a mild alkali.

Solvent Test:
The test involves treating the fibers in certain solvents for identifying them. The technical test is becoming difficult to conduct as most of the manufactured fibers and their blends are chemically similar. There is no individual chemical or solvent test for separating or identifying the fibers in combinations

This technical fiber identification test has the following advantages and limitations:


  1. More reliable than the non technical tests.
  2. Used for both man made fibers and natural fibers.
  3. Easily conducted.


  1. Certain manufacturing and finishing processes like mercerizing, affects the appearance of the fibers under the microscope.
  2. Very dark colored fabrics cannot be identified under microscope.
  3. Dye stuffs must be removed from fabrics.

You may also like:

  1. Basic Concept of Textile Testing and Quality Control (TTQC)
  2. Why Textile Testing is Important
  3. List of Basic Tests of Textile Fabric
  4. Different Types of Textile Testing Methods
  5. Classification of Textile Testing: Fiber Testing, Yarn Testing, Fabric Testing

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