Natural fibers
Natural fibers
Natural fibers are textile fibers originally found in nature or obtained directly from artificially cultivated plants or artificially raised animals. They are an important source of materials for the textile industry. The production of all-natural fibers is large and growing and they are an important source of materials for the textile industry.
Although synthetic fiber production has grown rapidly since the mid-20th century, natural fibers still account for approximately 50% of the total annual textile fiber production.
There are many types of natural fibers. There are four types of natural fibers that have been widely used in textiles for a long time: cotton, linen, wool, and silk. Cotton and linen are plant fibers, while wool and silk are animal fibers. Asbestos is found in rock formations in the earth’s crust and is called mineral fiber. It is an important building material and can also be used for textile applications. Cotton fiber has a large output and a wide range of uses. It can be used to sew daily necessities such as clothes, sheets, and bedding. It can also be used as a material for canvas and conveyor belts, or made into tire batting for insulation and filling materials. Most of the hemp fiber is used to make packaging fabrics and ropes, and some high-quality hemp fiber can be used for clothing. The output of wool and silk is much less than that of cotton and linen, but they are excellent textile raw materials. Wool fiber is used to make woolen fiber, silk fiber is used to make satin, and clothes are sewn into them. They are gorgeous and solemn and deeply loved by people. Among textile fibers, only wool fiber has the ability to be pressed into felt. Wool fiber is also a good raw material for fiber carpets.
1. Plant fiber: The main component is cellulose, also known as natural cellulose fiber. It is fiber obtained from seeds, fruits, stems, leaves, etc. of plants. Depending on the part where it grows on the plant, it is divided into seed fiber, leaf fiber and stem fiber.
1. Seed fibers: cotton, kapok, etc.;
2. Leaf fiber: sisal, abaca, etc.;
3. Stem fiber: ramie, flax, hemp, jute, etc.
2. Animal fiber: The main component is protein, also known as natural protein fiber, which is divided into two categories: hair and glandular secretions.
1. Hair: sheep wool, goat hair, camel hair, rabbit hair, yak hair, etc.;
2. Glandular secretions: mulberry silk, tussah silk, etc.
3. Mineral fiber: The main component is inorganic matter, also known as natural inorganic fiber, which is inorganic metal silicate, such as asbestos fiber.
4. Chemical fiber
Fibers made from chemical spinning using natural or synthetic polymer compounds as raw materials. It can be divided into man-made fiber, synthetic fiber and inorganic fiber.
5. Man-made fibers
Textile fiber made from natural polymer materials such as cellulose and protein as raw materials through chemical processing, spinning and post-processing. It is made from fiber raw materials that have lost their textile processing value, and is artificially dissolved or melted and then spun. Its original chemical structure remains unchanged, and the fiber components are still cellulose and protein respectively. The resulting physical structure and chemical structure changes are derived It is composed of cellulose acetate fiber.
1. Regenerated cellulose fiber: viscose fiber, strong fiber, cupro fiber, etc.; (the difference is that they are dissolved in different solutions of caustic soda and sulfur dioxide)
2. Cellulose ester fiber: acetate fiber;
3. Regenerated protein fiber: soybean fiber, peanut fiber, etc.
6. Synthetic fibers
Fibers made from synthetic polymer compounds as raw materials through spinning.
1. Ordinary synthetic fibers: polyester, nylon, acrylic, polypropylene, vinylon, chlorine, etc.;
2. Special synthetic fibers: aramid, spandex, carbon fiber, etc.
7. Inorganic fiber: Fiber made from minerals, such as glass fiber, metal fiber, etc.
Identification method:
Natural fibers
Natural fibers
①Identification methods include hand feeling, visual inspection, combustion method, microscope method, dissolution method, drug coloring method and infrared spectroscopy method. In actual identification, it is often necessary to use multiple methods and obtain results after comprehensive analysis and research.
②The general identification steps are as follows:
A. First use the combustion method to identify natural fibers and chemical fibers.
B. If it is a natural fiber, use microscope observation to identify various types of plant fibers and animal fibers. If it is a chemical fiber, the differences in melting point, specific gravity, refractive index, solubility properties, etc. of the combined fiber can be distinguished one by one.
C. When identifying mixed fibers and blended yarns, you can generally use a microscope to confirm that they contain several fibers, and then use appropriate methods to identify them one by one.
D. For dyed or finished fibers, dyeing stripping or other appropriate pre-treatment is generally required first to ensure reliable identification results.
Identification method:
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: waist-round or polygonal, with a middle cavity; longitudinal 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 blue sky 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: melting; contacting the flame: melting, smoking; leaving the flame: continuing to burn, emitting black smoke; odor: spicy; residue characteristics: black irregular beads, brittle [2 ].
(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. biSST1
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