For the manufacture of textile materials, a wide variety of fibers are used, which should be classified taking into account their origin, chemical composition and other characteristics.
Depending on their origin, textile fibers are divided into natural and chemical. Chemicals, in turn, are divided into artificial and synthetic. Man-made fibers are obtained from natural fiber-forming polymers, such as cellulose. These include viscose, copper-ammonia, acetate, and protein fibers. Synthetic fibers are obtained by synthesis from low molecular weight compounds. The raw materials, as a rule, are petroleum products and coal. Synthetic fibers include polyamide, polyester, polyacrylonitrile, polyurethane, polyvinyl alcohol, etc. Synthetic fibers are widely used, their balance in general production textile fibers is increasing more and more. The classification of textile organic fibers is shown in Fig. 3.
Synthetic fibers and threads are also divided into heterochain and carbon chain. Carbon chain fibers are fibers and threads that are obtained from polymers that have only carbon atoms in the main chain of macromolecules (polyacrylonitrile, polyvinyl chloride, polyvinyl alcohol, polyolefin, carbon).
|
From cellulose: viscose polynosous copper-ammonia acetate, diacetate Protein: zein, casein collagen Made from natural rubber: rubber rubber |
Heterochain: polyamide (nylon, anide, enant) polyester (lavsan, terylene, dacron) polyurethane (spandex, lycra, viren) Carbon chain: polyacrylonitrile (Nitron, Orlon, Kurtel) polyvinyl chloride (chlorin, soviden) polyvinyl alcohol (vinol) polyolefin (polyethylene, polypropylene) made of synthetic rubber (rubber) |
Rice. 3. Classification of organic textile fibers
Heterochain fibers are formed from polymers, the main molecular chain of which, in addition to carbon atoms, contains atoms of other elements - O, N, S (polyamide, polyester, polyurethane).
Man-made fibers are mostly products of cellulose processing (viscose, polynose, copper-ammonium - cellulose hydrate; acetate, diacetane - cellulose acetate). Protein artificial fibers (zein, casein, collagen) are produced in small quantities from fibrillar proteins of milk, skin, and plants.
In the above classification (see Fig. 3), fibers and threads are classified as organic. They are mostly used for the production of textile materials for household use. In organic fibers, the macromolecules of the main chain contain atoms of carbon, oxygen, sulfur, and nitrogen. In addition to organic fibers, there are inorganic fibers, the macromolecules of the main chain of which contain inorganic atoms (magnesium, aluminum, copper, silver, etc.). Inorganic natural fibers include asbestos fibers, chemical inorganic fibers include glass fibers and metal fibers made from steel, copper, bronze, aluminum, nickel, gold, silver in various ways (alunite, lurex).
Author Chemical encyclopedia b.b. I.L. KnunyantsINORGANIC FIBERS, fibrous materials obtained from certain elements (B, metals), their oxides (Si, Al or Zr), carbides (Si or B), nitrides (Al), etc., as well as from mixtures of these compounds, for example various oxides or carbides See also Glass fiber, Metal fibers, Asbestos.
Production methods: spunbonding from the melt; blowing the melt with hot inert gases or air, as well as in a centrifugal field (this method produces fibers from fusible silicates, for example quartz and basalt, from metals and some metal oxides); growing monocrystalline fibers from melts; molding from inorganic polymers followed by heat treatment (oxide fibers are obtained); extrusion of finely dispersed oxides plasticized with polymers or fusible silicates with their subsequent sintering; thermodynamic processing of organic (usually cellulose) fibers containing salts or other metal compounds (oxide and carbide fibers are obtained, and if the process is carried out in a reducing environment, metal fibers are obtained); reduction of oxide fibers with carbon or transformation of carbon fibers into carbide fibers; gas-phase deposition on a substrate - on threads, strips of films (for example, boron and carbide fibers are obtained by deposition on a tungsten or carbon thread).
Mn. types of INORGANIC FIBERS c. modified by applying surface (barrier) layers, mainly by gas-phase deposition, which makes it possible to increase their performance properties (for example, carbon fibers with a carbide surface coating).
K INORGANIC FIBERS close to needle-shaped single crystals various connection(see Whiskers).
Most INORGANIC FIBERS c. are polycrystalline. structure, silicate fibers - usually amorphous. INORGANIC FIBERS obtained by gas-phase deposition are characterized by layered heterogeneity. structure, and for fibers obtained by sintering, the presence of a large number of holes. Fur. properties INORGANIC FIBERS c. are given in the table. The more porous the structure of the fibers (for example, those obtained by extrusion with afterbirth, sintering), the lower their density and mechanical properties. INORGANIC FIBERS stable in many aggressive environments, non-hygroscopic. B oxidize In the environment, oxide fibers are most resistant, and carbide fibers are less resistant. Carbide fibers have semiconducting properties, their electrical conductivity increases with increasing temperature.
BASIC PROPERTIES OF SOME TYPES HIGH STRENGTH INORGANIC FIBERS OF THE SPECIFIED COMPOSITION *
* Inorganic fibers used for thermal insulation and production of filter materials, have more low mechanical properties.
INORGANIC FIBERS and thread-reinforcing fillers in structures. materials having organic, ceramic. or metallic matrix. INORGANIC FIBERS (except boron) are used to produce fibrous or composite-fibrous (with an inorganic or organic matrix) high-temperature porous thermal insulation. materials; they can be used for a long time at temperatures up to 1000-1500°C. From quartz and oxide INORGANIC FIBERS. manufacture filters for aggressive liquids and hot gases. Electrically conductive silicon carbide fibers and threads are used in electrical engineering.
Literature: Konkin A. A., Carbon and other heat-resistant fibrous materials, M., 1974; Kats S.M., High-temperature heat-insulating materials
terials, M., 1981; Fillers for polymer composite materials, trans. from English, M., 1981. K. E. Perepelkin.
Chemical encyclopedia. Volume 3 >>
Inorganic yarn is made from compounds of chemical elements (except carbon compounds), usually from fiber-forming polymers. Asbestos, metals and even glass can be used.
This is interesting. The fine-fiber structure of natural asbestos allows it to be used to make yarn for fireproof fabric.
Types and features of production
Thanks to the variety of raw materials from inorganic fibers, it is possible to create different types of yarn. All of them are characterized by high tensile strength, excellent dimensional stability, wrinkle resistance, and resistance to light, water, and temperature.
Metallic, or metallized, yarn is widely used in the textile industry. It is used in combination with other types of material to give products a shiny, decorative appearance. To produce such yarn, they use either alunit - metal threads that do not tarnish or fade over time. The material is made of aluminum foil coated with polyester film, which protects against oxidation. To obtain a golden hue, copper is added to the raw material, and to add reinforcing properties, it is twisted with nylon thread.
To expand the range of textile products, inorganic fibers can be used in a mixture with other materials, including those of natural origin.
Historical background. The production of artificial yarn began in late XIX century. The first type of inorganic fiber was nitrate silk, produced in 1890.
Properties
The artificial origin of yarn from inorganic fibers has endowed it with many advantages:
- UV resistance - the yarn does not fade in the bright sun, maintaining its original color;
- good hygroscopicity, that is, the ability to absorb and evaporate moisture;
- hygienic - inorganic fibers are not of interest to moths, microorganisms do not multiply in them.
All products made from inorganic fibers have good wearability and retain their appearance for a long time.
Products made from such yarn require careful washing. The water should not be hot, optimally no more than 30–40 degrees. Otherwise, the item may shrink or lose strength.
It is recommended to use washing liquid of the appropriate type of fabric and an antistatic agent. It is impossible to squeeze things out of inorganic fibers by twisting: when wet, they lose up to 25% of their strength, which can lead to damage.
Advice. Do not use a machine spin or dry the product on a radiator. It is better to straighten the item on a flat horizontal surface, placing a towel that will absorb moisture, or oilcloth.
What is knitted from inorganic fibers
Inorganic fiber yarn is ideal for knitting or crocheting. Smooth shiny threads do not tangle or flake; even a beginner can easily handle them. From this yarn you can knit or decorate with metallic thread:
- elegant bolero;
- fashionable top;
- beautiful dress;
- bright headdress;
- lace napkin;
- booties or socks for the baby.
Inorganic fibers will allow you to create a beautiful and elegant item. Use your imagination and you will succeed!
Inorganic fibers in branded collections
To knit a quality product, you need to choose the right material. Yarn with inorganic fibers is offered by Lana Grossa and other manufacturers. They have gained immense popularity among knitters all over the world. Bright, beautiful and original collections of yarn will allow you to choose the ideal material for your work.
), their oxides (Si, Al or Zr), carbides (Si or B), nitrides (Al), etc., as well as from mixtures of these compounds, for example. diff. oxides or carbides. See also Glass fiber, Metal fibers, Asbestos.
Production methods: spunbonding from the melt; blowing the melt with hot inert gases or air, as well as in a centrifugal field (this method produces fibers from fusible silicates, for example, quartz and basalt, from metals and certain metal oxides); growing monocrystalline fibers from melts; molding from inorganic polymers with the last heat treatment (oxide fibers are obtained); extrusion of finely dispersed oxides plasticized with polymers or fusible silicates. their sintering; thermal processing org. (usually cellulose) fibers containing or other compounds. metals (oxide and carbide fibers are obtained, and if the process is carried out in a reducing environment, metal fibers are obtained); oxide fibers with carbon or the transformation of carbon fibers into carbide; gas-phase on a substrate - on threads, strips of films (for example, boron and carbide fibers are obtained by deposition on a tungsten or carbon thread).
Mn. types of N. v. modified by applying surface (barrier) layers, ch. arr. gas-phase deposition, which allows increasing their performance. properties (for example, with a carbide surface coating).
Most N. century. are polycrystalline. structure, silicate fibers - usually amorphous. Non-ferrous materials obtained by gas-phase deposition are characterized by layered heterogeneity. structure, and for fibers obtained by sintering, the presence of a large number. Fur. St. N. century. are given in the table. The more porous the structure of the fibers (for example, those obtained by extrusion with afterbirth, sintering), the lower their density and fur. St. N.v. stable in plural aggressive environments, non-hygroscopic. B oxidize environment max. resistant oxide fibers, to a lesser extent carbide. Carbide fibers have semiconductor properties, their electrical conductivity increases with increasing temperature.
BASIC PROPERTIES OF SOME TYPES HIGH STRENGTH INORGANIC FIBERS OF THE SPECIFIED COMPOSITION *
* Inorg. fibers used for thermal insulation and production of filter materials, have more low fur. St.
N.v. and reinforcing threads in structures. materials having org., ceramic. or metallic matrix. N.v. (except boron) are used to produce fibrous or composite-fibrous (with inorganic or organic matrix) high-temperature porous thermal insulation. materials; they can be used for a long time at temperatures up to 1000-1500°C. From quartz and oxide N. century. manufacture filters for aggressive liquids and hot gases. Electrically conductive silicon carbide fibers and threads are used in electrical engineering.
Lit.: Konkin A. A., Carbon and other heat-resistant fibrous materials, M., 1974; Kats S.M., High-temperature heat-insulating materials
terials, M., 1981; Fillers for polymer composite materials, trans. from English, M., 1981. K. E. Perepelkin.
Chemical encyclopedia. - M.: Soviet Encyclopedia. Ed. I. L. Knunyants. 1988 .
See what "INORGANIC FIBERS" are in other dictionaries:
They have an unorganized main chains and do not contain org. side radicals. The main chains are built from covalent or ionic covalent bonds; in some N. points, the chain of ionic covalent bonds can be interrupted by single coordination junctions. character...... Chemical encyclopedia
Obtained from metals (for example, Al, Cu, Au, Ag, Mo, W) and alloys (brass, steel, refractory, for example nichrome). They are polycrystalline. structure (about monocrystalline structure, see Whisker crystals). They produce fibers, monofilaments (thin wires) ... Chemical encyclopedia
heat resistant fibers- Synthetic fibers suitable for use in air environment at temperatures exceeding the thermal stability limits of conventional textile fibers. Obtained by molding from solutions of aromatic polyamides (see polyamide... ... Textile glossary
Quartz fibers (threads)- inorganic heat-resistant (high temperature-resistant) fibers (threads) with high dielectric, acoustic, optical, chemical properties. The listed properties determine wide application. K.N. in nuclear, aviation... Encyclopedia of fashion and clothing
Inorganic materials- – materials from inanimate, inorganic nature: stone, ores, salts, etc. These materials are ubiquitous. They are non-flammable and are used for the production of mineral binders, metals, concrete fillers, mineral fibers, etc.... ... Encyclopedia of terms, definitions and explanations of building materials
Substances or materials that are added to polymer compositions. materials (e.g. plastics, rubbers, adhesives, sealants, compounds, paint and varnish materials) for the purpose of modifying the operating St. in, facilitating processing, as well as reducing them ... Chemical encyclopedia
Polymer- (Polymer) Definition of polymer, types of polymerization, synthetic polymers Information about the definition of polymer, types of polymerization, synthetic polymers Contents Contents Definition Historical background Science of Polymerization Types ... ... Investor Encyclopedia
index- 01 GENERAL PROVISIONS. TERMINOLOGY. STANDARDIZATION. DOCUMENTATION 01.020 Terminology (principles and coordination) 01.040 Dictionaries 01.040.01 General provisions. Terminology. Standardization. Documentation (Dictionaries) 01.040.03 Services. Organization of companies... ... International Organization for Standardization (ISO) standards
MUSCLES- MUSCLES. I. Histology. Generally morphologically, the tissue of the contractile substance is characterized by the presence of differentiation of its specific elements in the protoplasm. fibrillar structure; the latter are spatially oriented in the direction of their reduction and... ...
LEATHER- (integumentum commune), a complex organ that makes up the outer layer of the entire body and performs a number of functions, namely: protecting the body from harmful external influences, participation in heat regulation and metabolism, perception of irritations coming from outside.… … Great Medical Encyclopedia
Article by G.E. Krichevsky, Doctor of Technical Sciences, Professor, Honored Scientist of the Russian Federation
Introduction
Currently, the most developed countries are moving into the 6th technological order, and developing countries are catching up behind them. This way of life (post-industrial society) is based on new, breakthrough technologies and, above all, nano-, bio-, info-, cognitive-, and social technologies. This new paradigm for the development of civilization affects all areas of human practice and affects all technologies of previous orders. The latter do not disappear, but are significantly modified and modernized. But, most importantly, a qualitative change is the emergence of new technologies, their transition to a commercial level, the introduction of products of these technologies and modified traditional technologies into the everyday life of a civilized person (medicine, transport of all types, construction, clothing, home interior and accessories, sports, army, means of communication, etc.).
Krichevsky G.E. – Professor, Doctor of Technical Sciences, Honored Worker of the Russian Federation, UNESCO expert, academician of RIA and MIA, Laureate of the State Prize of the MSR, member of the Nanotechnological Society of Russia.
This tectonic, technological shift did not bypass the field of fiber production, without which not only the production of textiles of all types, but many technical products of traditional and non-traditional applications (composites, medical implants, displays, etc.) is not possible.
Story
The history of fibers is the history of humanity, from primitive existence to modern post-industrial society. Without clothing, home interior, without technical textiles, everyday life, culture, sports, science, technology, and medicine are unthinkable. But all types of textiles do not exist without fibers, which at the same time are only raw materials, but without which it is impossible to produce all types of textiles and other fiber-containing materials.
It is interesting to note that many thousands of years ago, from the end of the Paleolithic era (~ 10-12 thousand years BC) until the end of the 18th century, man used exclusively natural (plant and animal origin) fibers . And only the first industrial revolution (2nd technological structure - mid-19th century) and, of course, advances in science and, above all, chemistry and chemical technologies gave rise to the first generation of chemical fibers (cellulose hydrate - copper-ammonia and viscose). From that moment until the present time, the production of chemical fibers has developed extremely quickly in terms of quantity (overtaken the production of natural fibers in 100 years) and in a number of positions in terms of quality (significant improvement in consumer properties). The history of fibers is briefly presented in Table 1, from which it follows that the history of chemical fibers has gone through three stages, and the last one has not yet ended and the third, young generation of chemical fibers is going through the stage of its formation. A SMALL TERMINOLOGICAL DEVICE
There are discrepancies in Russian (formerly Soviet) and international terms. According to Soviet and Russian terminology, fibers are divided into natural (plant, animal) and chemical (artificial and synthetic).
Let’s ask ourselves the question “doesn’t everything that surrounds us consist of chemical elements and substances?” And therefore they are chemical and, therefore, natural fibers are also chemical. The remarkable Soviet scientists who proposed this term “chemical” were, first of all, chemist-technologists and put into this term the meaning that they are not produced by nature (biochemistry), but are produced by man using chemical technologies. Chemical technology is placed in first place and dominates in this term.
International terminology denotes all artificial and synthetic fibers (polymers) in contrast to natural - not made by hands, as made by human hands (man-made) - manmade fibers. This definition is more correct from my point of view. With the development of polymer chemistry and fiber production technologies, terminology in this area also develops, becomes more precise, and becomes more complex. Terms such as polymer and non-polymer fibers, organic, inorganic, nano-sized fibers, fibers filled with nanoparticles obtained using genetic engineering, etc. are used.
Bringing terminology into line with advances in third-generation fiber production will continue; This needs to be monitored by both fiber producers and consumers in order to understand each other.
New, third generation of high-performance fibers (HEF)
Third generation fibers with such properties in foreign literature are called HEFs - high-performance fibers (HPF - High Performance Fibers) and, along with new polymer fibers, they include carbon, ceramic and new types of glass fibers.
The third, new generation of fibers began to form at the end of the 20th century and continues to develop in the 21st century, and is characterized by increased requirements for their operational properties in traditional and new areas of application (aerospace, automotive, other modes of transport, medicine, sports, army, construction). These areas of application place increased demands on physical and mechanical properties, thermo-, fire-, bio-, chemical-, and radiation resistance.
It is not possible to fully satisfy this set of requirements with a range of natural and chemical fibers of the 1st and 2nd generation. Advances in the field of chemistry and physics of polymers and physics come to the rescue solid and production of VEV on this basis.
Polymers with new chemical structures and physical structures are emerging (synthesized) using new technologies. Establishing the relationship, cause-and-effect relationships between the chemistry, physics of fibers and their properties underlies the creation of 3rd generation fibers with predetermined properties and, above all, high tensile strength, resistance to friction, bending, pressure, elasticity, thermal and fire resistance.
As can be seen from Table 1, which presents the history of fibers, the development of fibers occurs in such a way that the previous types of fibers do not disappear when new ones appear, but continue to be used, but their importance decreases, and new ones increase. This is the law of historical dialectics and the transition of products from one technological structure to another with a change in priorities. All natural fibers, 1st and 2nd generation chemical fibers are still used, but new 3rd generation fibers are beginning to gain strength.
Production synthetic fibers, fiber-forming polymers, like most modern organic low- and high-molecular substances, are based on oil and gas chemistry. The diagram in Figure 1 shows numerous products of primary and advanced processing of natural gas and oil, up to fiber-forming polymers, 2nd and 3rd generation fibers.
As you can see, plastics, films, fibers, medicines, dyes and other substances can be obtained from oil and natural gas through deep processing.
In Soviet times, all this was produced, and the USSR occupied the leading (2–5) places in the world in the production of fibers, dyes, and plastics. Unfortunately, at present, all of Europe and China use Russian gas and oil and produce many valuable products from our raw materials, including fibers.
Before the advent of chemical fibers in a number of technical areas natural fibers (cotton) were used, having strength characteristics of 0.1–0.4 N/tex and an elastic modulus of 2–5 N/tex.
The first viscose and acetate fibers had a strength no higher than natural ones (0.2–0.4 N/tex), but by the 60s of the 20th century it was possible to increase their strength to 0.6 N/tex and their elongation at break to 13% (due to modernization of classical technology).
An interesting solution was found in the case of Fortisan fiber: elastomeric acetate fiber was saponified to hydrated cellulose and a strength of 0.6 N/tex and a modulus of elasticity of 16 N/tex were achieved. This type of fiber lasted in the world market during the period 1939–1945.
High strength indicators are achieved not only due to the specific chemical structure of the polymer chains of fiber-forming polymers (aromatic polyamides, polybenzoxazoles, etc.), but also due to a special, ordered physical supramolecular structure (molding from a liquid crystalline state), due to high molecular weight (high total energy of intermolecular bonds), as in the case of a new type of polyethylene fiber.
Since modern ideas about the mechanisms of destruction of polymer materials and fibers in particular come down to the ratio of the strength of chemical bonds in the main chains of the polymer and intermolecular bonds between macromolecules (hydrogen, van der Waals, hydrophobic, ionic, etc.), then the game is on to increase strength on two fronts: high-strength single covalent bonds in the chain and high strength of total intermolecular bonds between macromolecules.
Polyamide and polyester fibers entered the world market (Dupont) in 1938 and are still present today, occupying a large niche in traditional textiles and in many areas of technology. Modern polyamide fibers have a strength of 0.5 N/tex and an elastic modulus of 2.5 N/tex; polyester fibers have similar strength and a higher elastic modulus of 10 N/tex.
It was impossible to further increase the strength properties of these fibers within the framework of existing technologies.
The synthesis and production of para-aramid fibers spun from a liquid crystalline state with strength characteristics (strength 2 n/tex and elastic modulus 80 n/tex) was started by DuPont in the 60s of the 20th century.
In the last decades of the last century, carbon fibers with a strength of ~ 5 hPa (~ 3 N/tex) and an elastic modulus of 800 hPa (~ 400 N/tex), new generation glass fibers (strength ~ 4 hPa, 1.6 N/tex), appeared. elastic modulus 90 hPa (35 N/tex), ceramic fibers (strength ~3 hPa, 1 N/tex), elastic modulus 400 hPa (~100 N/tex).
Table 1 History of fibers
| *item no.** | *Type of fiber** | *Time of use** | Technological structure | Scope of application |
|---|---|---|---|---|
| I | NATURAL – MADE | |||
| 1a | Vegetable: cotton, flax, hemp, ramie, sisal, etc. | Developed 10–12 thousand years ago; are still in use today | All pre-industrial technological and all industrial technological | Clothing, home, sports, medicine, army, limited technology, etc. |
| 1b | Animals: wool, silk | |||
| II | CHEMICAL – MANUFACTURED | |||
| 1 | 1st generation | |||
| 1a | Artificial: cellulose hydrate, copper-ammonia, viscose | End of the 19th – 1st half of the 20th centuries, until now | 1st–6th technological structures | Clothing, home, sports, medicine, limited technology |
| 1b | Acetate | |||
| 2 | 2nd generation | |||
| 2a | Artificial: lyocell (cellulose hydrate) | 4th quarter of the 20th century to the present | 4th–6th technological structures | Clothing, medicine, etc. |
| 2b | Synthetic: polyamide, polyester, acrylic, polyvinyl chloride, polyvinyl alcohol, polypropylene | 30s – 70s of the 20th century to the present | Clothing, home, appliances, etc. | |
| 3 | 3rd generation | |||
| 3a | Synthetic: aromatic (para-, meta-) polyamides, high molecular weight polyethylene, polybenzoxazole, polybenzimidazole, carbon | 5th–6th technological structures | Technology, medicine | |
| 3b | Inorganic: new types of glass fibers, ceramic | late 20th – early 21st centuries | 6th technological structure | Technique |
| 3v | Nano-sized and nano-filled fibers |
The 3rd generation of chemical fibers in foreign literature is called not only highly efficient (HEF), but also multifunctional and smart. All these and other names and terms are not precise, controversial, at least not scientific. Because all existing fibers, both natural and chemical, are, of course, to one degree or another, highly effective and multifunctional, and intelligent. Take, for example, natural fibers such as cotton, flax, and wool; not a single chemical fiber can surpass their high hygienic properties (they breathe, absorb sweat, and flax is still biologically active). All fibers have not one, but several functions (multifunctional). As you can see, the above terms are very conditional.
Physico-mechanical properties of VEV
Since the main areas of use of the new generation of fibers (cord for tires, composites for aircraft, rocket, automotive, construction) are putting forward high demands to the properties of fibers and, above all, to the physical and mechanical properties, then we will dwell in more detail on these properties of high-energy materials.
What physical and mechanical properties are important for new areas of fiber use: tensile strength, abrasion strength, compressive strength, twisting strength. At the same time, it is important for fibers to withstand repeated (cyclic) deformation effects adequate to the operating conditions of products containing fibers. Figure 2 very clearly shows the difference in the requirements for physical and mechanical properties (tensile strength, elastic modulus) that three areas of use impose on fibers: traditional textiles, traditional technical textiles, new areas of application in technology.
As can be seen, the demands on the strength properties of fibers from new and traditional applications are increasing significantly, and this trend will continue as the areas of fiber use expand. A striking example is the space elevator, which is talked about not only by science fiction writers, but also by engineers. And this project can only be realized using ultra-strong cables made from 3rd generation nanofibers and spider silk type fibers (stronger than steel thread).
Figure 2
Explanations for Fig. 2: The modulus of elasticity and tensile strength are assessed in the same units. The elastic modulus is a measure of the rigidity of a material, characterized by its resistance to the development of elastic deformations. For fibers, it is defined as the initial linear relationship between load and elongation. Den (denier) is a unit of measurement of the linear density of a thread (fiber) = mass of 1000 meters in g. Tex is a unit (non-system) of measurement of the linear density of a fiber (thread) = g/km.
Table 2 shows comparative characteristics of the physical and mechanical properties of various fibers, including VEV.
Table 2. Comparative characteristics physical and mechanical properties of various fibers
It should be borne in mind that physical and mechanical properties should be assessed not by one indicator, but at least by a combination of two indicators, i.e. strength and elasticity under various types of deformation effects.
So, according to the data in Table 2, the steel thread wins in elasticity, but loses in specific gravity(very heavy). Taking into account all the indicators together, you can choose the areas of use of fibers. So the cable for a space elevator should not only be super strong, but also lightweight.
The fabric for a bulletproof vest must be light, elastic (drape) and capable of absorbing the kinetic energy of a bullet (depending on the burst energy, i.e. the ability to dissipate energy). The composite for racing cars must be impact-resistant and light at the same time; Seat belts must be made of high-strength fibers with high elasticity.
The requirements for the physical and mechanical characteristics of fibers, as a set or combination of two or more indicators, can be continued. This set of properties and factors is formulated by the user based on the operating conditions of products containing fibers. Let us trace the change in generations of fibers using the example of tire cord, the requirements for the physical and mechanical characteristics of which have been increasing all the time.
When the first automobiles appeared (1900), cotton yarn was used as tire cord; with the advent of hydrated cellulose viscose fibers in the period 1935–1955. they have completely replaced cotton. In turn, polyamide fibers (various types of nylon) replaced viscose fibers. But even classical polyamide fibers today do not meet the strength properties of the automotive industry, especially in the case of tires for heavy vehicles and aviation. Therefore, polyamide cord is now replaced by steel threads.
The maximum strength of commercial polyamide and polyester fibers reaches ~ 10 g/den (~ 1 GPa, ~ 1 N/tex). The combination of moderately high strength and elasticity provides high rupture energy (work of rupture) and high resistance to repeated shock deformation. However, these performance indicators of polyamide and polyester fibers do not meet the requirements of certain new applications of fibers.
For example, polyamide and polyester fibers, due to the high increase in stiffness at high strain rates, do not allow their use in anti-ballistic products.
At the same time, polyester fibers are very suitable for high-strength fishing gear (ropes, ropes, nets, etc.), since they are characterized by relatively high strength and hydrophobicity (not wetted by water); ropes made of polyester fibers are used on drilling rigs to work at depths of up to 1000–2000 m, where they can withstand loads of up to 1.5 tons.
The combination of high strength and high modulus of elasticity is provided by three groups of high-energy materials: 1. based on aramids, high-molecular polyethylene, other linear polymers, carbon fibers; 2. inorganic fibers (glass, ceramic); 3. based on thermosetting polymers that form a three-dimensional network structure.
VEV based on linear polymers
The first group of VEVs are based on linear (1D dimensional) polymers and the simplest of them, polyethylene.
For materials made from linear polymers, back in 1930, Staudinger proposed an ideal model of a supramolecular structure that provides a high modulus of elasticity along the main chains (11000 kg/mm2) and only 45 kg/mm2 between macromolecules bound by van der Waals forces.
Figure 3. Ideal physical structure of a linear polymer according to Staudinger.
As you can see (Fig. 3), the strength of the structure is determined by the elongation and high orientation of the chains of macromolecules along the fiber axis.
The technology (state of the spinning solution and melt, drawing conditions) for the production of fibers must be designed in such a way that folds of macromolecules do not form. Fiber-forming polymers, with a certain chemical structure of macromolecules, already in solution form elongated, oriented structures combined into blocks (liquid crystals). When fibers are formed from such a state, reinforced by a high degree of elongation, a structure close to ideal according to Staudinger is formed (Fig. 3). This technology was first implemented by DuPont (USA) in the production of Kevlar fibers based on polyparaaramid and polyphenylene terephthalamide. In these high-strength fibers, the aromatic rings are linked by amide groups
The presence of cycles in the chain provides elasticity, and amide groups form intermolecular hydrogen bonds, which are responsible for tensile strength.
Using similar technology (liquid crystalline state in solution, high degree hoods when molding VEVs are produced from various polymers by different companies, in different countries under different trade names: Technora (Taijin, Japan), Vectran (Gelanese, USA), Tverlana, Terlon (USSR, Russia), Mogelan-HSt and others.
Carbon fibers and graphene layers
Large 2D-dimensional molecules do not exist in nature. Monofunctional molecules in reactions produce small molecules; bifunctional ones produce linear (1D-dimensional) polymers; three- or more functional reagents form 3D-dimensional, cross-linked network structures (thermoplastics). Only the specific geometry of the direction of the bonds that carbon atoms can form leads to layered molecules. Graphene, a hexonal, planar network of carbon atoms, is the first example of such a structure.
Carbon fibers are usually produced by high-temperature treatment (cracking) of organic fibers (cellulose, polyacrylonitrile) under tension. Strong, elastic fibers are obtained in which one-dimensional layers are oriented parallel to the fiber axis.
3D mesh structures
Polymers with a 3D network structure are usually called thermoplastics because they are formed in thermocatalytic condensation reactions of polyfunctional monomers.
3D thermoplastics can be produced in the form of fibers. Although heat-resistant, such fibers are not very strong. Examples of such fibers are fibers based on melamine-formaldehyde and phenol-aldehyde polymers*.
Inorganic 3D-dimensional mesh structures (glass and ceramic) and fibers based on them, as well as based on metal oxides and carbides, are characterized by high strength, elasticity, heat and fire resistance.
- The main polymer of wool fiber, keratin, is also a networked, sparsely cross-linked natural polymer. It has unique elastic-elastic properties (resistance to compression). Cross-linking of a linear cellulose polymer with rare cross-links gives the fiber and fabrics made from it resistance to creasing, which cellulose fibers do not initially possess. But at the same time, the tensile and abrasion strength decreases (~15%).
Figures 4–10 show comparative physical and mechanical characteristics of VEVs.
Table 3 shows the main performance characteristics natural and chemical fibers.
Figure 4. Load-elongation curves for conventional fibers and HEVs.
Figure 5. Relationship between specific strength and elastic modulus of HEV.
Figure 6. Dependence of mass strength on strength/volume for VEV.
Figure 8. Load-strain curves of a composite based on EEV in an epoxy matrix.
Figure 9. Breaking length in kilometers for VEV.
Figure 10. VEV. Main areas of use.
Table 3. Basic performance characteristics of natural and chemical fibers (Hearle).
| № | Fiber type | Density g/cm3 | Humidity, at 65% humidity | Melting point, °C | Strength, N/tex | Modulus of elasticity, N/tex | Work of rupture, J/g | Elongation at break, % |
| 1 | Cotton | 1,52 | 7 | 185* | 0,2–0,45 | 4–7,5 | 5–15 | 6–7 |
| 2 | Flax | 1,52 | 7 | 185* | 0,54 | 18 | 8 | 3 |
| 3 | Wool | 1,31 | 15 | 100**/300* | 0,1–0,15 | 2–3 | 25–40 | 30–40 |
| 4 | Natural silk | 1,34 | 10 | 175* | 0,38 | 7,5 | 60 | 23 |
| 5 | Viscose | 1,49 | 13 | 185* | 0,2–0,4 | 5–13 | 10–30 | 7–30 |
| 6 | Polyamide | 1,14 | 4 | 260*** | 0,35–0,8 | 1,–5 | 60–100 | 12–25 |
| 7 | Polyester | 1,93 | 0,4 | 258 | 0,45–0,8 | 7,–13 | 20–120 | 9–13 |
| 8 | Polypropylene-new | 0,91 | 0 | 165 | 0,6 | 6 | 70 | 17 |
| 9 | n-aramid | 1,44 | 5 | 550* | 1,7–2,3 | 50–115 | 10–40 | 1,5–4,5 |
| 10 | m-aramid | 1,46 | 5 | 415* | 0,49 | 7,5 | 85 | 35 |
| 11 | Vectran | 1,4 | < 0,1 | 330 | 2–2,5 | 45–60 | 15 | 3,5 |
| 12 | H.P.E. | 0,97 | 0 | 150 | 2,5–3,7 | 75–120 | 45–70 | 2,9–3,8 |
| 13 | PBO | 1,56 | 0 | 650* | 3,8–4,8 | 180 | 30–90 | 1,5–3,7 |
| 14 | Carbon | 1,8–2,1 | 0 | >2500 | 0,4–3,9 | 20–370 | 4–70 | 0,2–2,1 |
| 15 | Glass | 2,5 | 0 | 1000–12000**** | 1–2,5 | 50–60 | 10–70 | 1,8–5,4 |
continuation of table. 3
| 16 | Ceramic | 2,4–4,1 | 0 | >1000 | 0,3–0,95 | 55–100 | 0,5–9 | 0,3–1,5 |
| 17 | Chemoresistant | 1,3–1,6 | 0–0,5 | 170–375***** | 0–0,65 | 0,5–5 | 15–80 | 15–35 |
| 18 | Heat resistant | 1,25–1,45 | 5–15 | 200–500**** | 0,1–1,3 | 2,5–9,5 | 10–45 | 8–50 |
- – destruction; ** – softening; *** – for nylon 66, nylon 6 – 216°; **** – liquefaction;
***** – temperature range
Economics of VEV
In the 50s of the last century, polyamide and polyester fibers were literally a “miracle” for consumers who were hungry for an abundance of textile products with new properties. After the industrial development of fibers of this type by the world's largest chemical concern DuPont (USA), all the leading chemical companies in developed capitalist countries rushed after them and began producing similar fibers under different names.
The chemical industry of the USSR did not stand aside either, focusing on one type of polyamide fiber - nylon based on polycaproamide. This technology was exported from Germany for reparations in 1945. A prominent Soviet polymer scientist, Professor Zakhar Aleksandrovich Rogovin, took part in the dismantling of German factories that produced this fiber called perlon. He, together with a group of Soviet scientists and engineers, established the production of nylon at a number of factories in various cities of the USSR (Klin, Kalinin (Tver)).
Polyester fibers based on polyethylene terephthalate were produced on a large scale in the USSR under the trademark Lavsan - an abbreviation for the Laboratory of High Modulus Compounds of the Academy of Sciences. These two fibers became the main high-tonnage ones and still remain so in the world. These fibers are very widely used by themselves or mixed with other fibers both in the production of clothing, home textiles, and in the technical sector.
The world balance of fiber production and consumption in 2010 is shown in Figure 11.
Figure 11.
Figure 12.
Polyester. 2000 – 19.1 million tons;
2010 – 35 million tons;
2020 – 53.4 million tons.
Cotton. 2000 – 20 million tons;
2010 – 25 million tons;
2020 – 28 million tons.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Before moving on to the economics of VEV, let’s say how the pricing and investment policy for the production of polyamide and polyester fibers was built. At the beginning (30–40s of the 20th century) polyamide and polyester fibers were several times more expensive than natural cotton and even wool fibers. It’s hard to believe now, when the picture is the opposite and corresponds to the real cost of production of these fibers. But this was an absolutely correct pricing policy, typical for the beginning of a potentially mass product entering the market. This pricing policy allows significant income to be allocated to subsequent research on the development and improvement of the production of new types of fibers, including VEV. Currently, polyamide and polyester fibers are produced by many companies in many countries in large quantities. Such competition and large runs of these fibers have led to prices quite close to cost.
The situation is different, more complex, in the case of the VEV economy. DuPont, starting research in the field of aromatic polyamides, which led to the creation of Kevlar fiber from them (based on n-polyaramid), initially focused them on the tire cord market.
The appearance of heavy and high-speed cars and heavy aircraft required high-strength cord; Not only cotton and viscose fiber did not meet these requirements, but also much stronger polyamide and polyester fibers.
Increasing the strength of the cord proportionally increased the service life of the tires (“mileage”) and saved the consumption of fibers for the production of cord.
Kevlar and other high-strength EVs are used for specialty tires (racing cars, heavy trailers). Due to the specifics of the market for their consumption, VEVs are produced to order in small batches, by a small number of manufacturers using a much more complex technology (multistage synthesis, expensive raw materials, complex technology molding, high draw ratio, exotic solvents, low molding speeds) and, of course, by high prices. But those areas of technology in which HEVs are used (aircraft and rocket production) can afford to consume fibers at high prices, which are unacceptable in the case of the production of clothing and home textiles.
The production of the most used wind turbines reaches ~ 10 thousand tons per year, highly specialized ones - 100 tons per year or less (Fig. 19).
Figure 19.
The exception is HEVs based on high molecular weight polyethylene, since both the raw material (ethylene) and the polymer are produced using a well-known, relatively simple technology. It is only necessary at the polymerization stage to ensure the formation of a polymer with a high molecular weight, which determines the excellent physical and mechanical characteristics of this type of fiber. Prices on the world market for high-energy fibers are high, but vary greatly and depend on many factors (fiber fineness, strength, type of yarn, etc.) and market conditions (raw materials). Therefore in different sources we find large fluctuations in prices (Table 4). So for carbon fibers the price ranges from 18 DS/kg to 10,000 DS/kg.
It is much more difficult to predict the dynamics of price changes for VEVs than for large-tonnage traditional fibers (tens of millions of tons are produced per year), and investing in large-scale production of VEVs is a very risky business. The most capacious market for VEVs is the production and consumption of a new generation of composite materials, catalyzing work to improve the technology for the production of VEVs.
So far, new factories are not being built for the production of VEVs, but they are produced at existing factories on special pilot installations and lines.
Of course, the army, sports, medicine (implants), construction and, of course, aviation and aeronautics are real and potential users of VEVs. Thus, a 100 kg reduction in aircraft weight due to a new generation of lightweight and durable composites reduces annual fuel costs by 20,000 DS per aircraft.
For any innovation there is a risk of investment, but without risk there is no success. It is only in a student project that a business plan can be accurately calculated. Paper will endure anything.
The founder of the world famous automobile company Honda, Soichiro Honda, said well about this: “Remember, success can be achieved through repeated trial and error. Actual success is the result of 1% of your work and 99% of your failures.” Of course, this is hyperbole, but not far from the truth.
Table 4 Prices for various VEVs in comparison with polyester technical fiber
| №№ | Fiber type | Price in DS/kg |
| 1 | 2 | 3 |
| 1. | Polyester | 3 |
| 2. | High modulus polymer fibers | |
| n-aramid | 25 | |
| m-aramid | 20 | |
| high molecular weight polyethylene | 25 | |
| Vectran | 47 | |
| Zylon (polybenzoxazole RBO) | 130 | |
| Tensylon (SSPE) | 22–76 | |
| 3. | Carbon fibers | |
| based on PAN fibers | 14–17 | |
| based on petroleum pitch (regular) | 15 | |
| based on petroleum pitch (high modulus) | 2200 | |
| based on oxidized acrylic fibers | 10 |
continued table 4
| 1 | 2 | 3 |
| 4. | Glass fibers | |
| E-type | 3 | |
| S-2-type | 15 | |
| Ceramic | ||
| SiC-type: Nicolan NI, Tyrinno Lox-M, ZM | 1000–1100 | |
| stonchometric type | 5000–10000 | |
| Alumina-type | 200–1000 | |
| boron-type | 1070 | |
| 5. | Heat and chemical resistant | |
| REEK | 100–200 | |
| Basofil thermoplastics | 16 | |
| Kynol thermoplastics | 15–18 | |
| PBI | 180 | |
| PTFE | 50 |
Production modern species fibers (polyester, polyamide, acrylic, polypropylene and, of course, VEV) in the Russian Federation is extremely justified from the point of view of the huge reserves of natural raw materials (oil, gas) for the production of fibers and their great need for the modernization of a significant number of industries (oil, gas processing , textile, shipbuilding, automotive industry). Half of the world (excluding the USA, Canada, Latin America) uses our raw materials to make all this and sell it to us with high added value. The production of new generation chemical fibers can play the role of a locomotive for the development of the domestic industry, becoming one of important factors national security of the Russian Federation.
Used literature:
- G.E. Krichevsky. Nano-, bio-, chemical technologies and the production of a new generation of fibers, textiles and clothing. M., publishing house "Izvestia", 2011, 528 p.
- High Performance Fibers. Hearle J.W.S. (ed.). Woodhead Publishing Ltd, 2010, p.329.
Military textiles. Edited by E Wilusz, US Army Natick Soldier Center, USA. Woodhead Publishing Series in Textiles. 2008, 362 rub.
- PCI Fibers. Fiber Economics in an Ever Changing World Outlook Conference. www.usifi.com/…look_2011pdf
Abbreviation for fiber names
| English | Russian |
| Carbone HS | carbon |
| HPPE | high strength polyethylene |
| Aramid | aramid |
| E-S-Glass | glass |
| Steel | steel |
| Polyamide | polyamide |
| PBO | polybenozxazole |
| Polypropelene | polypropylene |
| Polyester | polyester |
| Ceramic | ceramic |
| Boron | boron based |
| Kevlar 49,29,149 | aramid |
| Nomex | m-aramid |
| Lycra | elastomeric polyurethane |
| Teflon | polytetrafluoroethylene |
| Aluminum | based on aluminum compounds |
| Para-aramid | p-aramid |
| m-aramid | m-aramid |
| Dyneema | high molecular weight polyethylene HMPE |
| Coton | cotton |
| Acrylic | acrylic |
| Wool | wool |
| Nylon | polyamide |
| Cellulosic | artificial cellulose |
| PP | polypropylene |
| P.P.S. | polyphenylene sulfide |
| PTFE | polytetrafluoroethylene |
| Cermel | polyaramidimide |
| PEEK | polyetherketone |
| PBI | polybenzimidazole |
| P-84 | polyarimid |
| Vectran | aramatic polyester |
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