Commonly used textile raw material component identification methods
Commonly used textile raw material component identification methods
1. Hand visual inspection method: This method is suitable for textile raw materials in the form of loose fibers.
(1) Cotton fiber is shorter and thinner than ramie fiber and other hemp craft fibers and wool fibers, and is often accompanied by various impurities and defects.
(2) Hemp fiber feels thicker and harder.
(3) Wool fiber is curly and elastic.
(4) Silk is filament, long and slender, with special luster.
(5) Among chemical fibers, only viscose fiber has a large difference in strength between dry and wet states.
(6) Spandex yarn has very high elasticity and its length can be stretched to more than five times at room temperature.
2. Microscopic observation method: Identify fibers based on their longitudinal and cross-sectional morphological characteristics.
(1) Cotton fiber: cross-sectional shape: round waist, with a mid-waist; longitudinal shape: flat belt-shaped, with natural twists.
(2) Linen (ramie, flax, jute) fiber: cross-sectional shape: round or polygonal, with a middle cavity; vertical shape: horizontal sections and vertical lines.
(3) Wool fiber: Cross-sectional shape: round or nearly round, some with pith; Longitudinal shape: scales on the surface.
(4) Rabbit hair fiber: Cross-sectional shape: dumbbell shape, with pith; Longitudinal shape: scales on the surface.
(5) Mulberry silk fiber: cross-sectional shape: irregular triangle; longitudinal shape: smooth and straight, with vertical stripes.
(6) Ordinary viscose fiber: Cross-sectional shape: zigzag shape, sheath-core structure; Longitudinal shape: longitudinal grooves.
(7) Rich and strong fiber: cross-sectional shape: less tooth-shaped, or round or oval; longitudinal shape: smooth surface.
(8) Acetate fiber: cross-sectional shape: trilobal or irregular zigzag; longitudinal shape: longitudinal stripes on the surface.
(9) Acrylic fiber: cross-sectional shape: round, dumbbell-shaped or leaf-shaped; longitudinal shape: smooth or striped surface.
(10) Polypropylene fiber: Cross-sectional shape: nearly round; Longitudinal shape: smooth surface.
(11) Spandex fiber: cross-sectional shape: irregular shape, including round and potato-shaped; vertical shape: dark surface with unclear bone-shaped stripes.
(12) Polyester, nylon, polypropylene fiber: cross-sectional shape: round or special-shaped; longitudinal shape: smooth.
(13) Vinyl fiber: cross-sectional shape: round waist, sheath-core structure; longitudinal shape: 1 to 2 grooves.
3. Density gradient method: It identifies fibers based on the characteristics of different densities of various fibers.
(1) To prepare a constant density gradient liquid, the xylene carbon tetrachloride system is generally used.
(2) To calibrate the density gradient tube, the precision ball method is commonly used.
(3) Measurement and calculation: The fiber to be measured is deoiled, dried, and deaerated pre-treated. After being made into small balls and put into balance, the fiber density is measured according to the suspended position of the fiber.
4. Fluorescence method: Use ultraviolet fluorescent lamps to illuminate the fibers, and identify the fibers based on the different luminous properties of various fibers and the different fluorescent colors of the fibers. The fluorescent colors of various fibers are specifically displayed:
(1) Cotton, wool fiber: light yellow
(2), mercerized cotton fiber: light red
(3). Jute (raw) fiber: purple brown
(4), jute, silk, nylon fiber: light blue
(5), Viscose fiber: white purple shade
(6). Glossy viscose fiber: light yellow purple shade
(7) Polyester fiber: white light is very bright
(8) Vinyl optical fiber: light yellow purple shade.
5. Combustion method: According to the different chemical compositions of fibers, the combustion characteristics are also different, so that the major categories of fibers can be roughly distinguished. The combustion characteristics of several common fibers are compared as follows:
(1) Cotton, linen, viscose fiber, cupro fiber: close to the flame: do not shrink or melt; contact with the flame: burn quickly; leave the flame: continue to burn; smell: the smell of burning paper; characteristics of the residue: a small amount of gray black or gray white ash.
(2) Silk and wool fibers: close to the flame: curl and melt; contact with the flame: curl, melt, and burn; leave the flame: burn slowly and sometimes extinguish themselves; Odor: the smell of burning hair; Residue characteristics: loose and brittle black particles Or coke-like.
(3) Polyester fiber: close to the flame: melting; contacting the flame: melting, smoking, slow burning; leaving the flame: continuing to burn, sometimes extinguishing itself; odor: special aromatic sweetness; residue characteristics: hard black beads .
(4) Nylon fiber: close to the flame: melting; contacting the flame: melting, smoking; leaving the flame: self-extinguishing; odor: amino smell; residue characteristics: hard light brown transparent beads.
(5) Acrylic fiber: close to the flame: melt and shrink; contact with the flame: melt and smoke; leave the flame: continue to burn and smoke; smell: spicy; residue characteristics: black irregular beads, brittle.
(6) Polypropylene fiber: close to the flame: melt and shrink; contact with the flame: melt and burn; leave the flame: continue to burn; odor: paraffin smell; residue characteristics: gray-white hard transparent beads.
(7) Spandex fiber: close to the flame: melting and shrinking; contacting the flame: melting and burning; leaving the flame: self-extinguishing; odor: peculiar smell; residue characteristics: white gelatin.
(8) Chloropropyl fiber: close to the flame: melt and shrink; contact with the flame: melt, burn, and emit black smoke; leave the flame: self-extinguishing; odor: pungent odor; residue characteristics: dark brown lumps.
(9) Vinyl fiber: close to the flame: melt and shrink; contact with the flame: melt and burn; leave the flame: continue to burn and emit black smoke; odor: unique fragrance; residue characteristics: irregular burnt brown lumps. taUoSFM7a5
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