If you are a lab technician working in a textile lab, you need to know fiber analysis from quantitative and qualitative aspects. Fibers are a base composition of textiles. Full knowledge of the fibers contributes to the textile lab’s work on developing qualified textile products. This article will guide you in learning about AATCC 20: Fiber Qualitative Analysis.
What is AATCC?
The American Association of Textile Chemists and Colorists, or AATCC, is a standard used in the United States for laboratory analysis of textile materials. This technique allows us to distinguish between the fiber blends based on their morphology and burning properties. The AATCC 20 standard provides the morphological structure of fibers that differ from one another in particular.
What is AATCC 20?
The AATCC 20 standard provides a test method for the morphological structure of fibers that differ from others.
Fiber Composition Test method (AATCC 20 Test Method)
This standard describes the physical, chemical, and microscopic techniques for identifying textile fibers used commercially in industries. Fibers may be examined in row form used in the construction of cloths. Composition is determining the qualitative number and ratio of fibers within a fabric. The largest sector of the textile industry that aids in fabric creation is fiber composition. This standard is used to identify generic fiber types defined by textile fiber products.
How are fibers classified? The AATCC 20 test method applies to the fibers including:
- Natural fibers
- Synthetic fibers
- Protein fibers
AATCC 20 describes the number of procedures for microscopical examination, solubility in a solvent, melting point, and refractive index used to identify the combination of fiber types. Some procedures are more effective for certain fibers for identifying natural and synthetic fibers than other techniques.
The following steps are used to analyze the content of fibers in testing fabric qualitatively according to the AATCC 20 test method.
Visual Analysis
In this step, the lab technician performs the visual examination to check the type of fabrics (Knit, Woven, Denim, Twill, etc.). Fabric types indicate the construction of fibers in fabrics. We can also check the presence of elastane fibers in the inner side of yarns or within the yarns. Elastane fiber is added to cloths to give the stretch and it can be visualized in a single yarn and separated easily. Elastane comes in one or two forms. When two elastanes are twisted together, the strength of the fabric is boosted. Most versatile, low-weight, high-strength fibers are in single yarn form and can be separated manually.
- Knit fabric
Knit fabric has only one yarn in the construction of fabric. The fabric is reduced within the disclosing of fibers when yarn is revealed. When it comes to yarn construction, this is the simplest type utilized in knit clothing.
fiber construction of knit fabrics- Woven fabric
Woven fabric has two sidewise yarns used in the fabric’s construction. One side of woven fabric is the warp yarn, and the other is called Weft yarn. Both warp and weft yarn are interconnected in the formation of cloths. Woven fabric is the most selling type of fabric. Every piece of fabric is included in the knit and woven categories.
weft and warpBurning Test
This procedure is hazardous due to the flammability of different laboratory chemicals and other apparel products. So, when performing a burning test, put the sample into the safe shelf or fume hood, which is resistant to flam. Wear proper gloves, goggles, and other safety materials to prevent incidents.
Pick the fibers with a tweezer and perform the test. Concentrate on the burning of fiber to check their behavior and color on burning. All the fibers have different burning behaviors, which are different from each other.
Natural fibers and synthetic fibers show unique characteristics when burning. Natural fiber (Cotton, Linen, Hemp, etc.) does not melt during burning and produces a paper-like burning smell. Natural fiber converts into fine ash after burning, which has no beads. Synthetic fibers have different characteristics in burning. Synthetic fibers like Polyester, Nylon, and Acrylic show melting during burning and produce beads. Nylon manmade fiber produces a tire-like burning smell, easily differentiating it from other fibers. All the fibers have a unique smell, differentiating them during the burning test.
For Example:
Wool fiber produces a hair-like burning smell.
Polypropylene produces a very Petroleum odor smell.
The smell of burning rubber is a familiar odor.
Acrylic, Polyester, and nylon have a unique smell that can be recognized with experience.
For Example:
Wool fiber: It produces hair-like burning smell.
Polypropylene: It produces a very Petroleum odor smell.
Microscopic Analysis
Microscopic examination is helpful to characterize the fiber’s morphology. It must be used with caution on man-made fibers since they are frequently used for the modification of fibers.
The identification of fibers depends upon the experience and familiarity with fiber modifications. Otherwise, the chances of mistakes increase with time due to the wide variation of fibers’ appearance.
We make two types of slides to analyze fibers on a microscope in microscopic analysis.
- Longitudinal View
- Cross Section View
Longitudinal View
Take the representative yarn to examine the fibers’ appearance. If the sample is loose, only one yarn will be taken. In case they are woven, we take yarns from one side in knit and both sides (Warp and Weft). Open the fiber by twisting and cutting it from the portion in which it opens clearly. Now take the slide, add liquid (Liquid Paraffin) to the slide, and spread the fiber yarn properly and smoothly. Put the slide cover on it and clean the stage of the microscope. Pick the slide and fix it on the microscope stage in good manners. Adjust the light of the microscope according to the view to analyze fibers. Move the stage and analyze all the fibers that are counted under the slide cover.
Cross-Section View
Natural fibers show a wide variation in cross-section view. A sufficient amount of fibers should be examined to cover the range of appearance of fiber structure. Cross-section slides one such type: Stainless steel plate drilled with 0.09 cm diameter holes. Microtome is also used to make cross-section slides.
In the cross-section view, we take fibers and fix them into the slide used to analyze. Cut the fibers from the upper and lower sides in the cross side with a sharp blade or sterilized cutter. Now examine the slide under adjustable light and view of the microscope. Move the microscope stage and analyze the bead’s shape of fiber which can be easily distinguished by their morphology.
Related Resources
AATCC 20A Fiber Fineness Integrated Tester YG (B) 002(002-I)