There are different types of textile fibers used in the apparel and various types of yarns.Therefore it is necessary to learn the different methods to identify different textile fibers.
There are some different tests which can be used for the identification of the textile fibers such as burning test, microscopic test, solubility test, optical test, density test etc. We would be discussing the basic tests like burning, feeling, microscopic and chemical tests of identifying the textile fibers. Non technical tests are feeling tests and burning tests.
These tests are useful and simple to perform and also provide ready identification under certain circumstances.
- Microscopic Identification: Positive identification of many natural fibers is possible using the microscope
2. Solubility: The chemical structure of polymers in a fiber determines the fiber’s basic solubility characteristics
3. Heating and Burning Characteristics: The reaction of fibers to heat from an open flame is a useful guide in the identification of fibers.
4. Density or Specific Gravity: Fiber density may be used as an aid in fiber identification
5. Staining: Fibers have differing dyeing characteristics and affinities dependent on the chemical and morphological structure of the fiber.
Structural, Chemical and Physical Identification:
The various methods are:
- Optical and Electron Microscopy: Optical microscopy (OM) has been used for many years as a reliable method to determine the gross morphology of a fiber in longitudinal as well as cross-sectional views.
- Elemental and End-Group Analysis: The qualitative and quantitative analysis of the chemical elements and groups in a fiber may aid in identification and characterization of a fiber.
- Infrared Spectroscopy: Infrared spectroscopy is a valuable tool in the determination of functional groups within a fiber.
- Ultraviolet-Visible Spectroscopy: The ultraviolet-visible spectra of fibers, dyes, and finishes can provide clues concerning the structure of these materials, as well as show the nature of electronic transitions that occur within the material as light is absorbed in various wavelengths by unsaturated groups giving an electronically excited molecule.
- Nuclear Magnetic Resonance Spectroscopy: Nuclear magnetic resonance (NMR) spectroscopy measures the relative magnitude and direction (moment) of spin orientation of the nucleus of the individual atoms within a polymer from a fiber in solution in a high-intensity magnetic field.
- X-Ray Diffraction: X-rays diffracted from or reflected off of crystalline or semicrystalline polymeric materials will give patterns related to the crystalline and amorphous areas within a fiber.
- Thermal Analysis: Physical and chemical changes in fibers may be investigated by measuring changes in selected properties as small samples of fiber are heated at a steady rate over a given temperature range in an inert atmosphere such as nitrogen.
- Molecular Weight Determination: Molecular weight determination methods provide information concerning the average size and distribution of individual polymer molecules making up a fiber.
- Mechanical and Tensile Property Measurements: Mechanical and tensile measurements for fibers include tenacity or tensile strength, elongation at break, recovery from limited elongation, stiffness (relative force required to bend the fiber), and recovery from bending.
- Specific Gravity: The specific gravity of a fiber is a measure of its density in relation to the density of the same volume of water, and provides a method to relate the mass per unit volume of a given fiber to that of other fibers.
- Environmental Properties: Environmental properties include those physical properties which relate to the environment in which a fiber is found. Moisture regain, solvent solubility, heat conductivity, the physical effect of heat, and the electrical properties depend on the environmental conditions surrounding the fiber.
- Chemical Properties: The chemical properties of fibers include the effects of chemical agents including acids, bases, oxidizing agents, reducing agents, and biological agents such as molds and mildews on the fiber and light- and heat-induced chemical changes within the fiber.