Fibers of plant and living origin, chemical fibers. Structure and properties of natural fibers Animal fibers
Natural fibers
Fibers are made up of unspun strands of material or long, thin pieces of thread. Fibers are used in nature by both animals and plants to hold tissues (biological).
Natural fibers are fibers that exist in nature in a finished form; they are formed without direct human intervention. This group includes fibers of plant, animal and mineral origin.
The main characteristics for classification are: the chemical composition of the fibers and the region of their origin. The classification of natural fibers is presented in the figure.
Let's take a closer look at the main ones.
Natural fibers of animal origin
Silk - consists of fiber of animal (protein) origin. Silk threads are obtained from the cocoons of silkworm caterpillars. The silk group includes fabrics such as voile, chiffon, crepe de chine, cardigan satin, crepe, crepe georgette, toile, faille, taffeta, brocade, foulard, etc. Traditionally, silk is considered one of the most expensive types of fabric. Products made from silk fabric are very light, durable, and beautiful. They have a pleasant shine and regulate body temperature well. The disadvantages of silk include the fact that the fabric wrinkles heavily and is sensitive to ultraviolet rays. Often other types of fibers are added to natural silk fiber to obtain new interesting textures and various spectacular weaves. It is worth noting that artificial and synthetic silk fabrics are also produced.
Wool is a natural fiber of animal (protein) origin. Animal hair is used as raw material - sheep wool, camel wool, llama wool, rabbit wool, etc. The group of wool fabrics includes: twill, broadcloth, tweed, Boston, covercotte, Cheviot, duvetin, etc. The wool of different animals differs in quality, properties and areas of application. The only common characteristic of all types of wool is their exceptional ability to retain heat. A significant amount of wool (94-96%) for textile industry enterprises is supplied by sheep farming. Natural wool fabrics are soft, elastic, light, breathable. The thickness of the fabrics can be different; there are both thick and thin woolen fabrics. Wool fabrics practically do not wrinkle.
Natural fiber of mineral origin: asbestos
natural fiber mineral vegetable
Asbestos (Greek: indestructible) is the collective name for a group of fine-fiber minerals from the class of silicates. In nature, these are aggregates with a spatial structure in the form of the finest flexible fibers. It is used in a wide variety of fields, such as construction, the automotive industry and rocket science. In terms of its chemical composition, asbestos is aqueous silicates of magnesium, iron, and calcium and occurs in rocks in the form of veins and streaks.
Natural fibers of plant origin
The main substance that makes up plant fibers is cellulose. This solid, poorly soluble substance consists of C6H10O5 units. In addition to cellulose, plant fibers contain waxes, fats, proteins, dyes, etc.
Cotton is a natural fiber of plant origin. Cotton is produced from the fibers of the seeds of cotton plants. The following fabrics are produced based on cotton: satin, cambric, gauze, chintz, denim, flannel, rosin, teak, calico, marquisette, percale, nansook, organdy, pique, poplin, voile and other fabrics. The advantages of cotton fabric are: strength, high wear resistance, alkali resistance and elasticity. The fabric is warm, soft and pleasant to the touch, absorbs moisture well, and does not electrify. The disadvantage of the fabric is high creasing due to the low proportion of elastic deformation. Sometimes viscose is added to cotton group fabrics, and then an amazing shine or pattern appears on their matte surface.
Linen is a natural and environmentally friendly fiber of plant origin. The raw material for flax production is the stem of a herbaceous plant of the same name. Linen fabrics are hygienic, durable, soft to the touch, with good moisture and breathability properties. However, linen fabrics, due to the insignificant elongation and weak elasticity of the fibers, wrinkle extremely badly and are difficult to iron, and also shrink considerably during washing. Most often, products made from linen fabric are produced in natural colors (from gray to beige). They have a pleasant shine.
Jute has long been used to make rope and burlap, and as a natural backing for carpets and linoleum. Jute fiber is obtained from the plant of the same name, which grows mainly in India and Bangladesh. Woven jute flooring is softer than coconut or sisal flooring and is therefore only suitable for areas where there is little traffic, such as bedrooms. Here the texture of jute products will be an additional advantage - it is pleasant to walk on them barefoot.
Coconut fiber (coir) is obtained from the nuts of the coconut palm. Coir is used to make durable and resilient floor coverings - carpets, mats and door mats. Coconut fiber is extremely durable, but it is scratchy and difficult to dye.
Hemp (hemp stem fibers) is extremely durable, does not rot and is not afraid of salt water, and does not fade or deteriorate in bright light. Hemp grown for the textile industry has no active narcotic components. It grows beautifully and does not require chemical protection or feeding. It is used to make hemp and coarse cloth. When combined with other, softer natural fibers, hemp produces lightweight, comfortable fabrics that can be used in a variety of ways.
Rattan is a vine native to Southeast Asia. Rattan fibers are used to weave baskets, mats and chair seats.
Sisal is incredibly durable and wear-resistant. This coarse natural fiber is obtained from the leaves of the agave plant. Sisal mats, mats and rugs can be used in high traffic areas. The material is softer than coconut fiber, but coarser than wool. Sisal does not have water-repellent properties; water stains it. But it is easy to dye, and there is more choice of colors here than with other natural fibers.
Textile fibers can be natural or chemical.
Natural fibers are those that are found in nature. Fibers consist of substances related to high molecular weight compounds - polymers. Of the naturally occurring substances, polymers, for example, include cellulose - the main part of plant fibers, keratin and fibroin - the main protein substances that make up wool and silk.
The most important natural textile fiber is cotton. At cotton gin plants, raw cotton (cotton seeds coated with cotton fiber) is cleaned of plant impurities (parts of bolls, leaves, etc.) that came during cotton harvesting, and then the fibers are separated from the seeds using special machines - fiber separators. The fiber is then pressed into bales and sent to a spinning mill.
The length of cotton fibers is generally just over 20 mm. Cotton fiber is thin but durable and dyes well. Thin, uniform and durable yarn is obtained from cotton and a wide variety of fabrics are made from it - from the finest cambric and voile to thick upholstery fabrics and cord for car tires.
Textile fibers are also obtained from the stems and leaves of plants. Such fibers are called bast. They can be thin (linen, ramie) and coarse (hemp, jute, etc.). Various fabrics are made from fine fibers, and burlap, ropes and cords are made from coarse fibers.
Wool has long been known to people. The bulk of wool comes from sheep. In terms of its importance for the national economy, wool ranks second after cotton. It has many very valuable properties: it is light, conducts heat poorly and absorbs moisture well. At primary processing factories, wool is freed from dirt and foreign impurities. Fibers that are identical in their properties are combined into common batches. Wool is used to make smooth, thin yarn, as well as fluffy, thick yarn. Fabrics made from smooth yarn are durable, lightweight, and wrinkle less. They are used to make various clothes - dresses, suits, coats. Fluffy and thick yarn is used to produce heavy fabrics (cloth) that are thick and have a fleecy surface. Wool is the only natural fiber from which various felts and other elastic and dense materials can be obtained by felting (entangling the fibers).
This is how natural silk is obtained. When the time comes for the silkworm caterpillar to turn into a pupa and then become a butterfly, it releases a thin thread. With its help, the caterpillar attaches itself to a dry branch and weaves a shell from this thread - a cocoon. The cocoons are collected, heated with steam and unwound using special machines. When unwinding, the threads of several cocoons (from 3 to 30) are connected, which are firmly glued together with a special substance - sericin, contained in the threads themselves. This thread is called raw silk. After twisting the raw silk, twisted silk is obtained, from which beautiful and durable knitwear is made.
There is a fiber of mineral origin - asbestos (mountain flax), from which thermal and electrical insulation, fire suits, etc. are made.
The need for chemical fibers arose already in the 19th century. The world's population was growing rapidly, new branches of technology were beginning to develop, consuming large quantities of fiber, and natural raw materials - cotton, wool, flax and silk - were in short supply.
There are 2 main types of fibers called chemical - artificial and synthetic. The simplest for chemical technology of the late XIX - early XX centuries. It turned out to be the creation of artificial fiber obtained by chemical processing of natural high-molecular compounds, such as cellulose, the main component of wood. The great Russian chemist D.I. Mendeleev attached great importance to the creation of artificial fiber from cellulose. He wrote: “A pound of finished fiber will cost less than a pound of cotton. In this alone a great future is already visible...”
Currently, viscose copper-ammonia, acetate and other artificial fibers are produced from cellulose. They are used to make staple and silk fabrics, cord and many other household and industrial products. Artificial fibers are cheaper than natural fibers and are superior to them in a number of properties. By changing the nature and modes of chemical processing of cellulose into fiber, it is possible to influence its strength, chemical resistance, elasticity, and thickness. However, the ability to change the properties of artificial fibers is still limited, since they are based on the same high-molecular compound as the basis of natural ones.
A completely different matter is synthetic fibers, the production of which turned out to be only possible with modern chemistry. Synthetic fibers are produced by polymerization of relatively simple chemical monomers. Using monomers of different nature and directed influence on the conditions of the polymerization reaction and the process of spinning fibers from a polymer melt or solution, it is possible to synthesize fibers with many predetermined properties. The raw materials for synthetic fibers are practically inexhaustible - oil, natural gas, coal and coke oven gas, waste from pulp and paper, food and other industries.
Resistance to aggressive environments, high mechanical strength, elasticity and other valuable qualities of synthetic fibers have made them indispensable for use in modern technology. Particularly durable cord for tires of modern cars, aircraft, ropes and cables that are superior to steel, filter partitions, semi-permeable membranes, numerous fabrics - this is not a complete list of the uses of only one synthetic fiber - nylon. But now the industry produces dozens of brands of synthetic fibers - nylon, enant, lavsan, nitron... And each new type of fiber comes with new areas of application, sometimes the most unexpected.
The production of chemical fibers can be divided into 4 stages. The first is obtaining the source material. If the raw materials for the production of artificial fibers are natural high-molecular compounds, then they are first purified from impurities. For synthetic fibers, this stage consists of polymer synthesis. Then the spinning mass is prepared. At this stage, the polymers are dissolved or transferred to a molten state. Next, the solution or melt is thoroughly cleaned of undissolved particles and air bubbles and dyes are added. The third stage is fiber formation. This is the most important and responsible operation. The spinning mass is pressed through a spinneret - a disk with many small holes. Thin streams emerging from the holes are blown with air, and the fiber hardens due to the evaporation of the solvent or cooling of the melt. The last one is fiber finishing. The fibers are cleaned of impurities that got on them during the spinning process. Often at this stage the fiber is also treated with a fat-containing solution to make it more slippery. This makes fiber processing easier in textile factories. The production of chemical fibers is completed by drying and winding the fiber onto spools and reels.
The fiber is ready. Now its path lies to factories and factories, where it will be turned into a wide variety of products.
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Many things that we use every day, for example, clothes, interior items, bed linen, etc., are made from fabrics that have different properties. Fabrics is a type of structural materials. Comparing fabric samples, you can see that they are different, first of all, in thickness. It depends on the threads from which the fabric is made and the way they are woven together.
If you pull the threads from the edge of the fabric, untwist and fluff them, we will see that they consist of a large number of small, thin, but flexible and strong fibers, which are called dragged by us. For such a study, you can use a teaching microscope or a magnifying glass. The length of the fibers is many times greater than their transverse dimensions and can range from 5 mm in cotton to tens and hundreds of meters in natural silk.
Textile fibers divided by natural And chemical Natural fibers are those found in nature. (Fig. 29). Fibers are natural of plant origin: cotton, flax, hemp, jute, agave and others; animal fibers: natural silk, wool; mineral origin(rock) - asbestos (see diagram).
Scheme
Chemical fibers are obtained artificially from various materials - wood processing products, oil, gas, coal, etc. Man-made fibers have properties that natural fibers do not have and complement or replace them. Chemical fibers include nylon, lavsan, etc.
Translated from Greek the word asbestos means “non-destructive”, “inextinguishable”. Material from the site
The most important feature of asbestos products is fire resistance. Therefore, this mineral fiber is a raw material for the production of fire-resistant fabrics and cardboard.
Under a microscope, textile fibers look like this:
Textile is a fiber that is used to make yarn, thread, fabrics and nonwovens.
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Goals and objectives: Educational: To familiarize students with the technological process of producing chemical fibers. To familiarize students with the properties of fabrics made from artificial and synthetic fibers. Developmental: Contribute to the formation and development of students’ cognitive interest in the subject. Contribute to the formation and development of the intellectual qualities of the individual. Develop logical thinking. Educational: To foster practicality and promote the development of aesthetic taste.
Production of chemical fibers Stage I: Obtaining a spinning solution. For artificial fiber: Dissolving cellulose mass in alkali. For synthetic fiber: the addition of chemical reactions of various substances. Stage II: Fiber formation. Passing the solution through dies. The number of holes in the die is thousands. The solution hardens to form hard, thin threads. Stage III: Fiber finishing. The threads are washed, dried, twisted, and treated with high temperature. Bleached, dyed, treated with soap solution.
Fabrics of synthetic origin polyester fibers polyamide fibers polyacrylonitrile fibers elastane fiber lavsan crimplen dederon nylon acrylic nitron dorlastan lycra Raw materials - gas. As a result of complex chemical reactions, fibers are obtained
Laboratory work: Determination of the composition of fabrics by their properties Properties of fabrics of a fabric sample Gloss Smoothness Softness Wrinkling Shedding Strength Dry Wet Combustion
Determination of the fibrous composition of fabric Materials, tools, devices: samples of fabrics made of artificial and synthetic fibers, a needle, a vessel with water, crucibles for igniting threads. Work order 1. Examine fabric samples. Determine which ones have a shiny surface and which ones have a matte surface. 2. Determine by touch the degree of smoothness and softness of the samples. 3. Determine the wrinkling properties of the samples by holding them in your fist for 30 seconds and then straightening them out. 4. Remove two threads from each sample. Wet one of them. First break the dry thread, then the wet one. Determine how the strength of the thread has changed. 5. Remove one thread at a time from the samples and set fire to the crucible. Analyze the type of flame, smell and combustion residue. 6. Complete the report table and determine the fiber composition of each fabric sample.
Fastening the material Option 1 1. Artificial silk fiber is a fiber: a) acetate; b) polyester. 2. Artificial fibers include: a) viscose; b) polyamide; c) acetate; d) polyester; 3. Fabrics made from artificial silk fibers have the following properties: a) do not wrinkle; b) shiny; c) hard; d) have good heat-shielding properties; e) do not slip when cutting; e) they crumble a little. 4. Shedding of sections is stronger in fabrics: a) made of wool fiber; b) nylon threads; c) cotton fiber. Option 2 1. Synthetic fibers are obtained: a) from wood; b) oil; c) plants. 2.You can determine the fibrous composition of a fabric: a) by the color of the fabric; b) combustion test; c) appearance; d) to the touch. 3. When synthetic fiber fabric burns, the following is formed: a) gray ash; b) hard dark ball; c) a crumbling black ball. 4. Hygienic properties are better for fabrics: a) made of cotton fiber; b) viscose fiber; c) polyacrylonitrile fiber.
Natural fibers (cotton, flax and others) are the main raw materials for the domestic textile industry. They are made from various natural products.
Origin of natural fibers
Raw materials, we repeat, are obtained from various products. Depending on the material, the fibers differ from each other in quality, appearance, and other characteristics. At the same time, there is a category of the most commonly used raw materials. In the textile industry, they are in first place in terms of application. Their characteristics depend on the characteristics of the crops from which the raw materials are made. In addition, natural fibers of animal origin are used. These include, for example, wool and silk.
Properties of natural fibers
As mentioned above, the characteristics of raw materials depend on the characteristics of the products from which they are obtained. The most common are cotton fibers. They are obtained from a specially grown crop. Cotton is grown in more than 50 countries. It is a perennial heat-loving crop. The plant looks like a bush, the height of which is one meter or more. Every year, after flowering, fruits form on the crop. They are presented in the form of boxes with seeds. They are covered with from 7 to 15 thousand hairs. They are cotton fibers. The length of the hairs ranges from 12-60 mm. The longer they are, the better the quality of the yarn and fabric. Natural fibers produce textiles that can be easily dyed and otherwise processed. As a rule, raw materials for industry are white or brown in color. Meanwhile, currently cultivation technologies make it possible to obtain colored
Bast raw materials
Natural fibers obtained from the stems and leaves of various crops. These, for example, include jute, flax, nettle and others. Linen is considered the thinnest, most flexible and softest. These are first created into yarn. It is subsequently used to produce durable and soft fabrics. Linen comes in several types. The length of the fibers depends on the height of the stem. Fiber flax is considered the most valuable in an industrial sense. Its stems can reach a height of 0.8-1 m. Curly flax produces low-quality ones.
Process of obtaining raw materials
Ripe flax stems are pulled out along with the roots. This is necessary to maintain the length of the fibers. This process is called “pulling”. Previously, this was done manually. Currently, special combines are working in the fields. Flax threshing machines remove the seeds from the stems. The resulting straws are soaked in special pools or other bodies of water. Part of the flax stalk makes up the bast. It is located under the bark. It contains fibers in the form of thin ligaments. They are isolated from the stems in special factories. The enterprises use a special technology for separating fibers from the bark and then processing them. The soaked stems are dried. Then they are crushed and beaten. After this, the natural fibers are bleached because they have a light yellow color turning into steel.
Other crops
The fibers of other plants are coarse and tough. They are used mainly in the manufacture of ropes, canvas, burlap, ropes, etc. For example, hemp fiber - natural material and is similar to flaxseed in many ways. However, it is not that soft. In this regard, it is used, as a rule, in the production of canvas, burlap, twine, and ropes. Basts are obtained not only from the stems. For example, leaves can also be used as a raw material.
Silk
For its production, fibers are used that are obtained from silkworm cocoons. They are formed at a certain stage of caterpillar development. They weave a cocoon, which is an oblong egg-shaped shell. It consists of the finest fiber, which is woven into 40-50 layers. The thread is formed as follows. There are two holes on the head just below the caterpillar's mouth. They release a thick liquid that solidifies in the air. Her education is ongoing. As a result, 2 threads are formed, which are glued together with sericin. This is a special substance that is also secreted by the caterpillar. As a result, one thread is created, which is used to weave the cocoon.
Industrial processing
The color of the cocoon depends on the type of silkworm. They come in reddish-yellow, white, and yellowish colors. Other types of silkworms are also bred that weave soft pink, green, and blue cocoons. It should, however, be said that the natural color of the threads is not stable. In addition, colored fibers can subsequently complicate the dyeing process. Before subsequent use in industry, cocoons are bleached.
To obtain high-quality fibers, cocoons are treated with steam or hot air. The pupae contained in them are killed, and to prevent decomposition, they are dried. If this is not done, the insect will turn into a butterfly and begin to emerge from the cocoon. Accordingly, it will be subject to mechanical destruction, which negatively affects the quality of the threads. Before the fibers begin to wind, the cocoons are placed in pools filled with hot water. Then they are treated with steam and alkaline solutions. This is necessary to soften sericin. One cocoon produces about 400-1200 m of thread. However, it is very thin. Therefore, fibers from 3 to 30 cocoons are combined into one.
Wool
What other natural fibers are used in industry? Animals provide industry and wool. It is also processed to produce threads. Wool has a variety of qualities and characteristics. Differences are present in the fibers of one animal of different species. For example, from sheep wool, the most valuable is that obtained from fine-fleece and semi-fine-fleece sheep. During the cutting process, the hair is removed in a continuous layer. Fleece varies in quality. The most valuable fibers are located on the back, stomach, and shoulder blades. The fur on the legs and hindquarters is coarse. However, down is considered the highest quality and most valuable. Its fibers are flexible, elastic and thin. The quality of wool largely depends on the time of shearing. The fibers obtained in spring will be softer. They contain a large amount of fluff. In autumn it is almost absent from the wool. Therefore, such fibers are tough. However, autumn wool is cleaner than spring wool. Among the fibers there are:
- Awn is a thick fiber.
- Transitional hair. According to its characteristics, it occupies an intermediate place between awn and down.
- "Dead" hair. It is presented in the form of hard and low-strength fibers.
Processing Features
The properties of the yarn will depend on the quality of the fibers that were used to produce it. The best varieties are made from down. The quality of fibers is determined not only by their strength, softness, fineness, but also by their length. This, in turn, will depend on the breed of sheep. The length of the coat can reach 180-200 mm. Raw materials are always subject to primary processing. It includes sorting and cleaning of debris (clumps of earth, burrs, etc.). Then detachment and loosening are carried out. After this, the wool is washed and dried. Sorting is done manually. The fleece is laid out on special tables. Here it is divided into parts. In accordance with certain quality standards, the wool in the batch is selected. Washing is carried out with special compounds with the addition of detergents. This is necessary to remove fat particles.
Chemical raw materials
With the development of technology, it became possible to produce artificial and The main reason for the use of chemistry in the production of raw materials is the high demand for textiles. Available resources could not meet the needs of the population. The production of artificial raw materials is carried out using these, in particular, including cotton, wood and other cellulose, milk proteins, etc. These substances are subjected to chemical treatment with nitric, sulfuric, acetic acids, acetone, caustic soda, and so on. As a result, viscose, nitro silk, acetate, copper-ammonia silk are obtained.
Synthetic raw materials
They are obtained by processing various products. Among them: oil and coal, associated and natural gases, agricultural waste and pulp and paper production. High molecular weight resins are isolated from the substances. They act as the starting material for the production of synthetic raw materials. Processing and processing of resins is carried out using a special, rather complex technology. Among the most widespread are nylon, lavsan, nylon, Milan, polyvinyl chloride and others. Chemical raw materials are given certain quality characteristics in advance. In particular, it is durable, resistant to moisture, paint, etc.
Mixed raw materials
The chemical and natural fibers mentioned above are homogeneous materials. Meanwhile, today mixing of raw materials is becoming increasingly popular. The introduction of new technologies in textile production provides ample opportunities to obtain a huge range of yarn. Natural fibers can be mixed both with each other and with artificial and synthetic materials. For example, they combine nylon and flax, nylon and wool. To obtain half-silk and half-wool fabrics, not only the mixing of fibers is used. New weaving technologies are actively used. In particular, when creating a fabric, the warp threads are yarns of some fibers, and the weft are yarns of others.
Conclusion
The textile industry is considered one of the largest manufacturing sectors. To manufacture in-demand products, high-quality raw materials must be used. It must comply with GOSTs and undergo careful processing. This is important for fibers of any origin, including chemical ones. It is worth noting that advanced production technologies are constantly being introduced in the industry. This, in turn, requires the supply of new types of raw materials.
