Identification method of various fibers
One hand, visual method
It is based on the appearance, color, feel, and tensile properties of the fiber to identify the fiber, which can be separated from the natural fiber and chemical fiber. For example, the length of the natural fiber is poor, the chemical fiber length is generally more tidy. In natural fiber, cotton fiber is short and thin, often with various impurities and defects. Hemp fiber feel rough. Wool fibers are curly and elastic. Silk is a long, slender, with a special luster.
Chemical fiber, viscose fiber between dry and wet strength, high elongation, high elastic spandex. By using these features, they can be distinguished. Other chemical fiber due to appearance features are similar and in a certain extent can be artificially set, so it is difficult to use hand eye measurement to be distinguished.
Two, combustion experiment method
Combustion method is a quick and easy way to identify the large class of textile fiber. He is based on the different characteristics of the fiber to roughly distinguish between fiber. Identification method is a wisp of unknown fiber, with a pair of tweezers clamping, slowly close to the flame, observation of fibers near the flame, contact with the flame, leaving the flame burning, and the burning sends out the smell and combustion residues characteristic, rough fiber identification.
Acetate fiber: near the fire that melts and contracts. When the fire is burning, the burning rate is slow. Acetate fiber is also a regenerated cellulose fiber, but after the esterification of acetic acid has been a semi synthetic fiber, so it has a pungent sour taste of vinegar. Ashes to black, not only loose and brittle. Not burn into lumps.
Polyester: when burning, melting and curling smoke burning, flame yellow. When burning, the fragrance is sent out, the ashes are dark brown glass balls, and can be broken by hand.
Polyamide (nylon): in case of fire, and the other side melting, a slow burning, burning smokeless or slightly white smoke, a small flame, blue. When burning with celery fragrance. Ashes are light brown glass balls and are not easily broken.
Such as: close to the flame shrink rapidly, away from the fire is extinguished. Burning with a pungent chlorine smell. Ashes for amorphous black lumps.
Vinylon: when burning shrink rapidly, but slow burning. Flame is very little, there is black smoke. When burning with aldehyde flavor. Ash brown amorphous lump, can crush.
Pan: in case of fire melting while burning, burning speed is very slow. Flame is white, very bright. Sometimes there is a little black smoke, and the smell of fish. Ashes for small black hard sphere, crisp fragile.
Using combustion method to identify the fiber is simple and easy, but it is not easy to judge the blended products. Fabric is woven from the warp and weft direction (that is, straight and transverse direction) each extraction of a yarn respectively burning
Combustion method is only applicable to single component fibers, yarns and fabrics, and for the components of hybrid fiber, yarn and fabric, and after flame retardant or other finishing of fiber and textile, due to combustion characteristics change, is often difficult to use combustion were identified.
Three, microscope observation method
Microscope observation method is to use ordinary biological microscope to observe the shape of the transverse and longitudinal surface of unknown fiber, which is a kind of method used in the identification of fiber.
The morphological characteristics of natural fiber is more unique, such as wool surface with scales and cotton fiber with natural distortion, hemp fiber with cross section vertical stripes, silk section is a triangle, and chemical fiber cross section for the approximate circular must be verified with the use of other methods.
Identification method of several new type textile fiber fabric
At present, in the production of textile development utilization of a number of new regenerated fiber and other textile fiber blended, interleaving, to produce a variety of new textile fabric, the fabric components identification, we usually will weave fabric of warp and weft yarn spun out after, then the yarn untwisting the demolition of the fiber, differential analysis of the situation is as follows:
(1) to do longitudinal fiber film, under a microscope observation of longitudinal fiber morphology, can clearly distinguish whether it contains cotton and wool, the soybean protein fiber longitudinal form is with irregular trench and island shaped concave and convex, the surface is not smooth, the groove of the Tencel fiber, modal fiber, bamboo fiber, and viscose based chitin fiber and longitudinal surface morphology is different, also can distinguish between the initial.
(2) using the chip to make the section of the yarn, observing the cross section of the yarn under the microscope, it is easy to determine whether the cotton fiber, silk, Tencel fiber, Modal fiber, soybean protein fiber.
(3) modal fiber cross-section shape is similar to the round the waist and a smooth and skin and core layer, the and cotton fiber cross-section shape for a waist circular cavity is significantly different, and the vinylon fiber cross-section shape for skin and core layer of the round the waist is significantly different, can be distinguished.
(4) of Tencel fiber cross sectional shape is a circle, and polyester, acrylic similar; soybean protein fiber cross-section shape is flat dumbbell shaped and round the waist, similar to those of vinylon; silk cross-section shape is a triangle, and section is similar to the triangle of chemical fiber; these can then combustion method and dissolution method to distinguish and judge the cellulose fiber and plant protein fiber or chemical fiber.
(5) of bamboo fiber and viscose fiber cross-section shape although relatively similar, for zigzag, it is difficult to distinguish. Therefore, it can be used by coloring method and combustion method to distinguish, and by comparing their tensile properties to distinguish, the tensile breaking strength of bamboo cellulose is higher than that of viscose fiber, tensile elongation at break is smaller than that of viscose fiber; viscose chitin fiber and viscose fiber cross section, although the form are relatively similar, the edge is serrated, but viscose chitin fibre cross-sectional area of core layer have obvious small voids, and viscose fiber cross-section shape is sawtooth shaped, skin core layer. Then combustion method is verified and the ash color is slightly different, bamboo plain the ashes of fiber and viscose chitin fibre is gray and viscose fiber gray and white.
Four, solubility test method
Dissolution method is to use the fiber in different chemical reagents in the dissolution characteristics of different principles to identify fiber. It is suitable for all kinds of fiber and its products, widely used. In addition to the qualitative analysis of fiber varieties, it can be used for the quantitative analysis of all kinds of blended yarns, fabrics and two component fibers. This method is more accurate, reliable, and commonly used in other ways to make a preliminary identification, and then dissolved to be confirmed. But in the experiment, it is necessary to control the concentration, temperature and time of the chemical reagent, so as to obtain a more accurate result.
According to the above situation, the fiber identification procedure is the first to be a little unknown fiber finishing, can be used to burn the fiber is divided into cellulose fiber, protein fiber and synthetic fiber three categories. The cellulose fiber and protein fiber have different morphological characteristics, and they can be identified by microscope. Synthetic fiber is generally used to identify the dissolution method.
We are exposed to some groups of two or three fiber blended fabrics, which requires us to do fiber qualitative identification, and use appropriate methods for sample pretreatment, and then use the appropriate solvent to dissolve a fiber blended variety, the remaining fiber cleaning, drying, weighing and calculation.
For example: cotton cloth weight 1.0 g, with 75% of the sulfuric acid solution to cotton, insoluble is polyester, weighing 0.6 g, then the cloth containing 40% cotton, polyester containing 60%.
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