Basics test methods for fabric testing
Some test methods are common for all kinds of fabric testing and give basic ideas regarding fabric characteristics.
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| Basic fabric testing / Identifications |
Microscopy- Optical/visual identification test
Optical tests or showing fabric by microscope are the simplest fabric tests.
With the use of a microscope, the technician can see the fabrics from a close and magnifying view which is valuable for certain fibres to identify particular shapes and sizes of fibres.
However, this test method is slow and consumes more time because not much more information can be obtained about the cross-sections by viewing from the top and preparing cross-sectional samples takes great skill and time.
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| Visual Identification of the fabric |
Density test by the physical separation method
The density measurement test is based on the materials' physical properties regarding the water. The density test is done by observing a simple test of preparing a liquid in which the fibres will either sink or float. The porous fibres and fibre blends will skew the density results.
In this test, Various liquids are used to cover a spread of working densities depending on the density of the test material.
The density gradient column has necessitated the observing of the level to which a test specimen will sink in a column of liquid, the density of which increases uniformly from top to bottom. The column should be about 40–50 mm high and normally graduate from 0 at the top to 100 cm at the bottom. Up to three such columns can be positioned in a water bath controlled at 23 ± 1°C. A valuable attribute of this method is that the columns, when prepared, can be accurately calibrated with glass beads of known density.
Chemical test by chemical extraction
Chemical tests for fabric are comparatively cheap and simple methods. (However, it is the more complex and wider variable test.
In this test, the number of elements that can be detected in fibres is limited. (Therefore, for more accurate analysis another piece of equipment is needed.)
The solubility of the textile fibre is derived from a fabric sample by specific chemical reagents. These reagents are definitive using specific fabric identification.
Following are the solubility of the fibres under various chemical circumstances and their consequences.
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| Fabric test with chemical |
Staining test
Staining tests are used to estimate changes in fibre structure from one process to another.
In case of the changing of the fibre structure, the dye shade will be different from batch to batch. A characteristic that can be obtained from dyeing is whether the fibre is hydrophobic or hydrophilic because hydrophilic fibres are easier to dye.
The staining method can be used to group fibres into three groups. The first is cellulosic, the second is protein-based, and the third is artificial fibres.
The process is not suitable for deep-dyed samples because the chemical finishes can interfere with the process.
When fibres are white or off-white or when colour can be stripped from fibres, staining techniques may be used as a part of identification. Specially prepared mixtures of dyes are used to stain the fibres for a specified time and at a specified temperature. After staining, the fibre, yarn or fabric pieces are dried and then compared with a known sample.
Questions -
- What is microscopy–an optical/visual identification test?
- What is a density test?
- How density test is done by the physical separation method?
- Why the chemical test is done on fabric?
- How the chemical test is done by chemical extraction?
- What is the staining test?
References
Booth, J. E. :. (n.d.). Principles of textile testing an introduction to physical methods of testing textile fibres, yarns, and fabrics. London: National Trade Press Ltd,1961. from https://www.abebooks.co.uk/Principles-Textile-Testing-Introduction-Physical-Methods/19989810376/bd
Cenote, M. (2015). Google Books. In The SAGE Guide to Key Issues in Mass Media Ethics and Law (pp. 847–858). SAGE Publications, Inc.
Ferreiro López-Riobóo, J. I. (2015). Long-term (2001–2012) study of a proficiency testing scheme for textiles. Accreditation and Quality Assurance, 20(4), 239–245. https://doi.org/10.1007/s00769-015-1128-1
TEXTILE VALUE CHAIN. (2020, May 5). Textile Testing and quality control. TEXTILE VALUE CHAIN. https://textilevaluechain.in/in-depth-analysis/articles/textile-articles/textile-testing-and-quality-control/
Writer - DSPAT Team
