Elastic material obtained by vulcanization of rubber. Vulcanization of rubbers - obtaining rubber and ebonite. What is rubber vulcanization and what does it give
RUBBER (PRODUCT OF RUBBER VULCANIZATION)
(from Lat. resina - resin), vulcanizate, rubber vulcanization product (see Natural rubber, Synthetic rubbers). Technical R. - a composite material that can contain up to 15-20 ingredients that perform various functions in R. (see Rubber mixture). R.'s main difference from others. polymer materials(see. Plastics, Polymers) - the ability to large reversible, so-called highly elastic, deformations in a wide range of temperatures, including room and lower temperatures (see. Highly elastic state). The irreversible, or plastic, component of R.'s deformation is much less than that of rubber, since the macromolecules of the latter are linked in R. by cross-linked chemical bonds (the so-called vulcanization grid). Rubbers are superior to rubber in strength properties, heat and frost resistance, resistance to aggressive media, etc.
Classification. Depending on the temperature and other operating conditions in which the metal retains its highly elastic properties, the following main groups are distinguished.
R. of general purpose, operated at temperatures from -50 to 150 | С. Manufactured on the basis of natural, synthetic isoprene, stereoregular butadiene, butadiene-styrene, chloroprene rubbers and their various combinations. Heat-resistant R., intended for long-term operation at 150-200 | С. Ethylene-propylene and organosilicon rubbers, and butyl rubber are the basis of such R. For radials operated at higher temperatures (up to 300 ° C and higher), some fluorine-containing rubbers are used, as well as rubber-like polymers such as polyphosphonitrile chloride. Frost-resistant R., suitable for long-term operation at temperatures below -50 | C (sometimes up to -150 | C). To obtain them, rubbers with a low glass transition temperature are used (see Glass transition of polymers), for example, stereoregular butadiene, organosilicon, and some fluorine-containing. Such rubbers can also be obtained from non-frost-resistant rubbers, for example, butadiene-nitrile rubbers, by introducing certain plasticizers (esters of sebacic acid, etc.) into the rubber mixture. Oil- and petrol-resistant rubbers that are operated for a long time in contact with petroleum products, oils, etc. They are obtained from nitrile-butadiene, polysulfide, urethane, chloroprene, vinylpyridine, fluorine-containing rubbers, and some organosilicon rubbers. R., resistant to the action of various aggressive media (acid- and alkali-resistant, ozone-resistant, steam-resistant, etc.). Manufactured on the basis of butyl rubber, organosilicon, fluorine-containing, chloroprene, acrylate rubbers, chlorosulfonated polyethylene. Electrically conductive R. To obtain them, use is made of various rubbers filled with large quantities of electrically conductive (acetylene) soot. Dielectric (cable) R., characterized by low dielectric losses and high electrical strength. They are obtained from organosilicon, ethylene-propylene, isoprene rubbers filled with light mineral fillers. Radiation-resistant R. (X-ray protective, etc.). They are based on fluorine-containing, butadiene-nitrile, butadiene-styrene rubbers filled with lead or barium oxides.
In addition to the listed R., there are also vacuum, vibration, light, fire, water resistant, friction R., as well as medical, food, etc.
Mechanical properties of rubbers based on various rubber components1
Indicators
Natural
Synthetic isoprene
Stereoregular
butadiene
Butadiedn-a-methylstyrene-
oil-filled
Butyl rubber
Ethylene prop-
nitrile-butadiene
Chloroprene-
Stress at 300% elongation2, Mn / m2
Tensile strength2, Mn / m2
Relative extension, %
Tear resistance, kn / m, or kgf / cm
TM-2 hardness
Rebound elasticity,%
Internal friction modulus, Mn / m2
Abrasion coefficient, cm3l (kW h)
Endurance at multiple deformations, thousand cycles
1 Data for temperature 22 | 2 C; I - unfilled rubber; II - rubber filled with active soot.
2 1 MN / m 2 "10 kgf / cm 2.
Properties. The complex of R.'s properties is determined primarily by the type of rubber. Significant impact on mechanical characteristics R. (deformation, strength) provide a filler (see table), as well as the structure and density of the vulcanization network. The most important deformation property of R. — the modulus (the ratio of stress to deformation) depends on a number of factors: conditions of mechanical loading (static or dynamic); the absolute value of stress and strain, as well as the type of the latter (tension, compression, shear, bending); the duration or rate of loading, which is due to relaxation phenomena, that is, a change in R.'s reaction to mechanical action (see. Relaxation, Relaxation phenomena in polymers); composition (recipe) R.
In the region of relatively small deformation (< 100%) модуль Р. при растяжении на 5 порядков ниже модуля Юнга для стали [соответственно 0,5-8,0 и 2105 Мн / м 2 (5-80 и 2106 кгс / см 2)] (см. также Модуль высокоэластический, Модули упругости). В указанной области деформации модуль Р. при сдвиге примерно в 3 раза меньше, чем при растяжении. Вследствие практической несжимаемости Р. (коэффициент Пуассона 0,48-0,50 против 0,28-0,35 для металлов) объёмный модуль Р. на 4 порядка выше, чем модуль при растяжении.
The dependence of the R.'s modulus on its composition can in some cases be described by generalized ratios, the use of which makes it possible to predict the value of R.'s modulus and create a so-called. materials with desired properties.
Deformation of soot-filled R., characterized by high internal friction, causes the transformation of mechanical deformation energy into thermal energy. This explains the high amortization capacity of the R., an indirect characteristic of which is the rebound elasticity indicator. However, because of the low thermal conductivity of heat, repeated cyclic loading of massive items, such as tires, leads to their self-heating (so-called heat generation), due to elastic hysteresis. The consequence of this may be a deterioration in the performance properties of products.
Under real operating conditions, the R. is in a complexly stressed state, since various deformations act simultaneously on products. However, R.'s destruction is caused, as a rule, by the maximum tensile stresses. For this reason, the strength properties of R. are evaluated in most cases with tensile deformation.
R in conditions of prolonged exposure to high temperatures, oxygen, ozone, ultraviolet light (see Aging of polymers).
Application. The rubber industry is one of the most important suppliers of components and products for many sectors of the national economy. R. is an irreplaceable material in the production of tires, various shock absorbers and seals; it is also used for the manufacture of conveyor belts, driving belts, sleeves, and various household items, in particular, footwear (see Rubber products). From rubber, cable insulation, elastic electrically conductive coatings, prostheses (for example, artificial heart valves), parts of anesthetic apparatuses, catheters, tubes for blood transfusion, and much more. The volume of world production of goods from rhodium in 1974 exceeded 20 million tons. The largest consumers of rheumatism are the tire industry (over 50%) and the industrial rubber goods industry (about 22%).
Lit .: Koshelev F.F., Kornev A.E., Klimov N.S., General technology of rubber, 3rd ed., M., 1968; Reznikovsky M.M., Lukomskaya A.I., Mechanical tests rubber and rubber, 2nd ed., M., 1968; Strengthening Elastomers, ed. J, Kraus, trans. from English., M., 1968; Handbook of the rubber worker. Materials (edit) rubber production, M., 1971; Proceedings international conference on rubber and rubber, M., 1971; Lukomskaya AI, Evstratov VF, Fundamentals of predicting the mechanical behavior of rubbers and rubbers, M., [in press].
V.F.Evstratov.
Great Soviet Encyclopedia, TSB. 2012
See also the interpretations, synonyms, meanings of the word and what RUBBER (PRODUCT OF RUBBER VULCANIZATION) is in Russian in dictionaries, encyclopedias and reference books:
- RUBBER in the Big Encyclopedic Dictionary:
(from Lat. resina - resin) (vulcanizate) elastic material formed as a result of vulcanization of rubber. In practice, they are obtained from a rubber mixture containing ... - RUBBER in the Automotive Jargon Dictionary:
- tires ... - RUBBER in the Thieves Jargon Dictionary:
- 1) car, 2) red tape, 3) reserve, 4) ... - RUBBER in Miller's dream book, dream book and interpretation of dreams:
If in a dream you are wearing rubber clothes, it means that your impeccable reputation will be earned by the firmness and invariability of your moral position. If ... - PRODUCT
ECONOMIC - see ECONOMIC FOOD ... - PRODUCT in the Dictionary of Economic Terms:
TOURIST - see TOURIST PRODUCT ... - PRODUCT in the Dictionary of Economic Terms:
SUPPLY - see SUPPLY PRODUCT ... - PRODUCT in the Dictionary of Economic Terms:
LIMIT - see LIMIT PRODUCT ... - PRODUCT in the Dictionary of Economic Terms:
PUBLIC PUBLIC PRODUCT - see PUBLIC PUBLIC PRODUCT ... - PRODUCT in the Dictionary of Economic Terms:
REQUIRED - see PRODUCT REQUIRED ... - PRODUCT in the Dictionary of Economic Terms:
FINAL - see FINAL ... - PRODUCT in the Dictionary of Economic Terms:
INTELLIGENT - see INTELLIGENT PRODUCT ... - PRODUCT in the Dictionary of Economic Terms:
DAVALSKY - see DAVALSKY PRODUCT ... - PRODUCT
[from the Latin productus produced] 1) an object, a substance resulting from human labor; 2) in chemistry, a substance obtained chemically from ... - RUBBER in the Encyclopedic Dictionary:
s, pl. no, well. Elastic material obtained by vulcanizing rubber. Rubber - related to rubber, made of rubber. Elastic band - 1) ... - PRODUCT in the Encyclopedic Dictionary:
a, m. 1. Subject as a result of human labor (processing, processing, research, etc.). Oil distillation product. || Cf. ARTIFACT. 2. transfer. ... - RUBBER in the Encyclopedic Dictionary:
, -y, f. 1. Elastic material obtained by vulcanizing rubber. 2. A tire (in 2 values) made of such material (simple). * ... - PRODUCT in the Encyclopedic Dictionary:
, -a, m. 1. Subject as a result of human labor (processing, processing, research). Manufactured products. Exchange products. Oil distillation products. Book … - RUBBER
RESIN POROUS, see Porous rubber ... - RUBBER in the Big Russian Encyclopedic Dictionary:
RESINA (from Lat. Resina - resin) (vulcanizate), an elastic material formed as a result of vulcanization of rubber. In practice, they are obtained from rubbers. mixtures, ... - RUBBER
rubbers, rubbers, rubbers, rubbers, not rubbers, rubbers, rubbers, well, rubbers, rubbers, noisy rubbers, rubbers, not, ... - PRODUCT in the Complete Accentuated Paradigm by Zaliznyak:
product kt, product kty, product kta, product ktov, product ktu, product ktam, product kt, product kty, product ktom, product kty, product kte, ... - PRODUCT in the Dictionary for solving and compiling scanwords:
Product from ... - PRODUCT in the Thesaurus of Russian Business Vocabulary:
Syn: production, production, ... - PRODUCT in the New Dictionary of Foreign Words:
(lat.productus produced) 1) tangible or intangible result of human labor (object, scientific discovery, idea, etc.); 2) substance, ... - PRODUCT in the Dictionary of Foreign Expressions:
[lat. productus produced] 1. tangible or intangible result of human labor (object, scientific discovery, idea, etc.); 2. substance, ... - PRODUCT in the Thesaurus of the Russian language:
Syn: production, production, ... - PRODUCT in Abramov's Dictionary of Synonyms:
see product, ... - RUBBER
tires, bicycle rubber, vulcanizate, city, gummilastic, dupren, baskets, mipor, motor rubber, nairit, oppanol, foam rubber, tire, matched, sucrolite, thiokol, scrap rubber, formvar, haveg, ejosmith, ... - PRODUCT in the dictionary of Synonyms of the Russian language:
Syn: production, production, ... - RUBBER
f. 1) Elastic, water and air impermeable substance obtained as a result of vulcanization of rubber. 2) decomp. Products from such ... - PRODUCT in the New Explanatory Dictionary of the Russian Language by Efremova:
m. 1) A subject that is the result of human labor, activity. 2) Creation, generation, result of smth.... 3) Substance obtained by chemical or other means ... - RUBBER
rubber, ... - PRODUCT in the Dictionary of the Russian language Lopatin:
product, ... - RUBBER
rubber, … - PRODUCT in the Complete Spelling Dictionary of the Russian Language:
product, ... - RUBBER in the Spelling Dictionary:
rubber, ... - PRODUCT in the Spelling Dictionary:
product, ... - RUBBER
simple. N2 tire made of this material rubber elastic material obtained by vulcanization ... - PRODUCT in the Ozhegov Russian Language Dictionary:
Consequence, result, generation of something Lib Language - item of historical development. product food items, foodstuffs Dairy products. Stocks of products. product thing ...
Rubber Rubber (from Latin resina "resin") an elastic material obtained by vulcanization of rubber Rubbers Natural or synthetic elastomers characterized by elasticity, water resistance and electrical insulating properties, from which rubbers and ebonites are obtained by vulcanization
It is used for the production of tires for various vehicles, seals, hoses, conveyor belts, medical, household and hygiene products, etc.
The history of rubber begins with the discovery of the American continent. The indigenous population of Central and South America, collecting the milky sap of rubber trees (hevea), received rubber. Columbus also noticed that heavy monolithic balls made of black elastic mass used in the games of the Indians bounce much better than the leather ones known to Europeans
In addition to balls, rubber was used in everyday life: making dishes, sealing the bottoms of a pie, creating waterproof "stockings", rubber was also used as glue: with the help of it, the Indians glued feathers to the body for decoration. But Columbus's message about an unknown substance with unusual properties remained unnoticed in Europe , although it is undoubted that the conquistadors and the first settlers of the New World made extensive use of rubber
Truly Europe got acquainted with rubber in 1738, when the traveler Sh. Kodamin, who returned from America, presented rubber samples to the French Academy of Sciences and demonstrated a method of obtaining it. First time practical application rubber was not received in Europe
The first and only application for about 80 years was to make erasers to erase pencil marks on paper. The narrowness of the use of rubber was due to the drying and hardening of rubber It was only in 1823 that the Scottish chemist and inventor Charles Mackintosh found a way to restore elasticity to rubber. He also invented waterproof fabric, obtained by impregnating dense fabric with a solution of rubber in kerosene. This fabric was used to make waterproof raincoats (nicknamed "Macintosh" by the name of the inventor of the fabric), galoshes, waterproof mail bags
In 1839, the American inventor Charles Goodyear found a way to temperature stabilize the elasticity of rubber by mixing raw rubber with sulfur and then heating. This method is called vulcanization, and is probably the first industrial polymerization process. The product obtained as a result of vulcanization was named rubber After Goodyear's discovery, rubber was widely used in mechanical engineering as a variety of seals and sleeves and in nascent electrical engineering, the industry of which was in dire need of a good insulating elastic material for the manufacture of cables Vulcanization process
The developing mechanical engineering and electrical engineering, and later the automobile industry, consumed more and more rubber. This required more and more raw materials. Due to the increase in demand in South America, huge plantations of rubber plants began to arise and develop rapidly, growing these plants monoculturally. Later, the center for the cultivation of rubber plants moved to Indonesia and Ceylon.
After rubber began to be widely used and natural sources of rubber could not cover the increased demand, it became clear that it was necessary to find a replacement for the raw material base in the form of rubber plantations. The problem was aggravated by the fact that several countries monopolized the plantations (the main one was Great Britain), in addition, the raw materials were quite expensive due to the laboriousness of growing rubber plants and collecting rubber and high transport costs. The search for alternative raw materials went in two ways: The search for plants - rubber plants, which could be cultivated in subtropical and temperate climates; Production of synthetic rubbers from non-plant raw materials
The production of synthetic rubbers began to develop intensively in the USSR, which became a pioneer in this field. This was due to an acute shortage of rubber for an intensively developing industry, the lack of effective natural rubber in the USSR and the limitation of the supply of rubbers from abroad, as the ruling circles of some countries tried to interfere with the industrialization of the USSR. The problem of establishing large-scale industrial production synthetic rubber was successfully solved, despite the skepticism of some foreign experts
General purpose rubbers are used in products in which the very nature of the rubber is important and there are no special requirements for finished product Special-purpose rubbers have a narrower scope and are used to give a rubber-technical product (tires, belts, shoe soles, etc.) a given property, for example, wear resistance, oil resistance, frost resistance, increased grip on a wet road, etc.
The main properties of styrene butadiene are: high strength, tear resistance, elasticity and wear resistance.This rubber is considered the best general-purpose rubber due to excellent properties high abrasion resistance and a high percentage of filling. They are used for most rubber products (including chewing gum)
The main advantage of rubbers made from butyl rubber is resistance to the action of many aggressive media, including alkalis, hydrogen peroxide, some vegetable oils, and high dielectric properties. The most important area of application of butyl rubber is the production of tires. In addition, butyl rubber is used in the production of various rubber products that are resistant to high temperatures and aggressive environments, rubberized fabrics
One of the many areas of application is flooring for outdoor sports and playgrounds. Ethylene-propylene rubber is suitable for the production of hoses, insulation, anti-slip profiles, bellows. These rubbers have two significant disadvantages. They cannot be mixed with other common rubbers and are not oil resistant
[-CH2-CH = CH-CH2-] n - [-CH2-CH (CN) -] m Nitrile butadiene rubber is a synthetic polymer, a copolymerization product of butadiene with acrylonitrile very good oil and gasoline resistance oil hydraulic fluid resistance resistance to carbonic solvents resistance to alkalis and solvents wide operating range: from -57 ° C to + 120 ° C. poor resistance to ozone, sunlight and natural oxidants poor resistance to oxidized solvents
Chloroprene rubber crystallizes upon stretching, due to which rubbers based on it have high strength. It is used for the production of rubber products: conveyor belts, belts, sleeves, hoses, diving suits, electrical insulating materials. They also produce wire and cable sheaths, protective coatings. Adhesives and chloroprene latexes are of great industrial importance Chloroprene rubber - elastic light yellow mass
Silicone rubbers have a set of unique properties: increased thermal, frost and fire resistance, resistance to the accumulation of residual compression deformation, etc. They are used in very important areas of technology, and their relatively high cost pays off more long term operation in comparison with rubbers based on hydrocarbon rubbers
The main methods for producing rubber in nature:
1) rubber is obtained from the milky sap of some plants, mainly Hevea, whose homeland is Brazil;
2) cuts are made in the trees of the Hevea to obtain rubber;
3) the milky juice, which is released from the cuts and is a colloidal solution of rubber, is collected;
4) after that, it is subjected to coagulation by the action of an electrolyte (acid solution) or by heating;
5) rubber is released as a result of coagulation.
The main properties of rubber:
1) the most important property of rubber is its elasticity.
Elasticity Is the property to experience significant elastic deformations with a relatively small acting force, for example, to stretch, compress, and then recover old form after the termination of the force;
2) the property of rubber, which is valuable for practical use, is also impermeability to water and gases.
In Europe, rubber products (galoshes, waterproof clothing) began to spread from the beginning of the 19th century. The famous scientist Goodyear discovered rubber vulcanization method- converting it into rubber by heating it with sulfur, which made it possible to obtain strong and resilient rubber.
3) rubber has even better elasticity, in this no other material can compare with it; it is stronger than rubber and more resistant to temperature changes.
In terms of its importance in the national economy, rubber is on a par with steel, oil, coal.
Composition and structure of natural rubber: a) a qualitative analysis shows that rubber consists of two elements - carbon and hydrogen, i.e. it belongs to the class of hydrocarbons; b) its quantitative analysis leads to the simplest formula C 5 H 8; c) determination of the molecular weight shows that it reaches several hundred thousand (150,000-500,000); d) rubber is a natural polymer; e) its molecular formula is (C 5 H 8) n; f) rubber macromolecules are formed by isoprene molecules; g) rubber molecules, although they have a linear structure, are not elongated in a line, but repeatedly bent, as if rolled into balls; h) when the rubber is stretched, such molecules straighten, the rubber sample from this becomes longer.
Characteristic features of rubber vulcanization:
1) natural and synthetic rubbers are used mainly in the form of rubber, since it has a much higher strength, elasticity and a number of other valuable properties. To obtain rubber, rubber is vulcanized;
2) from a mixture of rubber with sulfur, fillers (soot is an especially important filler) and other substances, the necessary products are formed and subjected to heating.
26. Aromatic hydrocarbons (arenas)
Characteristic features of aromatic hydrocarbons:
1)aromatic hydrocarbons (arenas) Are hydrocarbons whose molecules contain one or more benzene rings, for example:
a) benzene;
b) naphthalene;
c) anthracene;
2) the simplest representative of aromatic hydrocarbons is benzene, its formula is C 6 H 6;
3) the structural formula of the benzene nucleus with alternating three double and three simple bonds was proposed as early as 1865;
4) known aromatic hydrocarbons with multiple bonds in the side chains, for example styrene, as well as multinucleated ones, which contain several benzene nuclei (naphthalene).
Methods for the production and use of aromatic hydrocarbons:
1) aromatic hydrocarbons are contained in coal tar obtained by coking coal;
2) another important source of their production is oil from some fields, for example, Maikop;
3) in order to satisfy the huge demand for aromatic hydrocarbons, they are also obtained by catalytic aromatization of acyclic petroleum hydrocarbons.
This problem was successfully resolved by N.D. Zelinsky and his students B.A. Kazansky and A.F. Plate, who carried out the conversion of many saturated hydrocarbons into aromatic ones.
So, from heptane C 7 H 16, when heated in the presence of a catalyst, toluene is obtained;
4) aromatic hydrocarbons and their derivatives are widely used to obtain plastics, synthetic dyes, medicinal and explosive substances, synthetic rubbers, detergents;
5) benzene and all compounds that contain a benzene nucleus are called aromatic, since the first studied representatives of this series were aromatic substances or compounds isolated from natural aromatic substances;
6) now this series also includes numerous compounds that do not have a pleasant smell, but possess a complex of chemical properties called aromatic properties;
7) many other aromatic polynitro compounds (containing three or more nitro groups - NO 2) are also used as explosives.
Rubber is used in the production of automobile tires and rubber products
Rubber products in industry (production).
To obtain rubberized fabrics, take linen or paper cloth and rubber glue, which is a rubber mixture dissolved in gasoline or benzene. The glue is thoroughly and evenly smeared and pressed into the fabric; after drying and evaporation of the solvent, a rubberized fabric is obtained. For the manufacture of a cushioning material that can withstand high temperatures, paronite is used, which is a rubber mixture into which asbestos fiber is introduced. This mixture is mixed with gasoline, passed through rollers and vulcanized into sheets with a thickness of 0.2 to 6 mm. To obtain rubber tubes, the rubber is passed through a syringe machine, where a highly heated (up to 100-110 °) mixture is pressed through the head required diameter... The result is a tube that is vulcanized. Durite sleeves are manufactured as follows: strips are cut out of calendered rubber and applied to a metal core, whose outer diameter is equal to the inner diameter of the sleeve. The edges of the strips are lubricated with rubber glue and rolled with a roller, then one or more layers of fabric are applied and coated with rubber glue, and a layer of rubber is applied on top. The assembled sleeve is then vulcanized. Automobile cameras are made from rubber tubes that are injected or glued along the tube. There are two ways to make chambers: mold and mandrel. Bottom chambers are vulcanized on metal or curved mandrels. These chambers have one or two transverse joints. After joining, the chambers at the junction are vulcanized. In the molded method, the chambers are vulcanized in individual vulcanizers equipped with an automatic temperature controller. To avoid sticking of the walls, talc is introduced into the chamber. Car tires are collected on special machines from several layers of special fabric (cord), covered with a rubber layer. Fabric frame, i.e. the skeleton of the tire is carefully rolled, and the edges of the layers of fabric are wrapped. Outside, the frame is covered in the running part with a thick layer of rubber, called a tread, and more thin layer carved. The tire thus prepared is vulcanized.
Storage of rubber products.
When storing rubber, the following conditions must be observed:
1. The air temperature should not be lower than 5 ° and not exceed 15 °; humidity 40-60%.
2. Lack of daylight, for which the windows should be covered with yellow or red paint that does not transmit ultraviolet rays.
3. Rubber products must lie on wooden racks, which must be located at a distance of at least 1 m from heating devices.
4. Rubber products should be wrapped in paper or cloth and packed in boxes; the sleeves should be stretched, but not left in the skeins. Tires cannot be stacked; they are recommended to be placed on the tread part in a row on the racks.
Sources: 1. Dzevulsky V.M. Metal and wood technology. - M .: State Publishing House of Agricultural Literature. 1995. S. 438-440.
Links
- N. Korzinov. Battle for rubber
Wikimedia Foundation. 2010.
See what "Rubber (rubber vulcanization product)" is in other dictionaries:
Rubber (from Latin resina - resin), vulcanizate, rubber vulcanization product (see Natural rubber, Synthetic rubbers). Technical R. is a composite material that can contain up to 15 - 20 ingredients, performing in R. a variety of ... ...
rubber- rubber - polymer material; product of vulcanization of rubber. It differs from other polymeric materials, such as plastics, in its ability to large reversible, so-called highly elastic, deformations in a wide temperature range. Rubber … Encyclopedia "Dwelling"
R. is the general name for a group of materials obtained by vulcanization of rubber. Technical R. is a product of vulcanization of a rubber compound containing from 5 6 to 15 20 different ingredients that facilitate the processing of rubber and give the product the necessary ... ... Encyclopedia of technology
Rubber- is a product of special treatment (vulcanization) of rubber and sulfur with various additives. Note. It differs from other materials in high elastic properties, which are inherent in rubber - the main raw material of rubber. ... ... Encyclopedia of terms, definitions and explanations of building materials
I Rubber (from Latin resina resin) vulcanizate, a product of vulcanization (see Vulcanization) of rubber (see Natural rubber, Synthetic rubbers). Technical R. composite material, which can contain up to 15-20 ingredients, ... ... Great Soviet Encyclopedia
rubber Encyclopedia "Aviation"
rubber- in the aircraft industry. R. is the general name for a group of materials obtained by vulcanization of rubber. Technical R. is a product of vulcanization of a rubber mixture containing from 5-6 to 15-20 different ingredients that facilitate the processing of rubber ... Encyclopedia "Aviation"
- (from Lat. resina resin), vulcanizate, rubber vulcanization product. mixtures (compositions containing rubber, vulcanizing agents, fillers, plasticizers, antioxidants and other ingredients). Construct. material possessing a complex of unique s ... Big Encyclopedic Polytechnic Dictionary
- (from Latin resina resin) (vulcanizate), an elastic material resulting from the vulcanization of natural and synthetic rubbers. It is a reticulated elastomer product of cross-linking of molecules of rubbers chem. connections. Receiving. R … Chemical encyclopedia
Rubber is a substance obtained from rubbery plants that grow mainly in the tropics and contain a milky liquid (latex) in the roots, trunk, branches, leaves or fruits, or under the bark. Rubber is a product of vulcanization of compositions based on ... ... Collier's Encyclopedia
Vulcanization is the process of heating rubbers thoroughly mixed with sulfur or sulfur-containing compounds, such as thiuram:
The mixture is heated at a temperature of 130 - 160 ° C. In this case, bonds of the type are formed between the rubber macromolecules:
and even polysulfide bonds:
if mass fraction sulfur in the mixture is great. The vulcanization process is shown below using the example of obtaining rubber from butadiene (divinyl) rubber. For the sake of simplicity, all cross-links are shown through a single sulfur atom. In fact, there may be disulfide bridges, and if ebonite is obtained, then bridges containing 8 sulfur atoms.
Rubber is an elastic material widely used for the manufacture of tires for automotive vehicles and aircraft, for conveyor belts and escalator handrails. And also for the manufacture of hoses, seals, divers' suits and chemical protection, boats, shoes.
To obtain rubber, the mass fraction of sulfur in the mixture with rubber must be in the range from 0.5 to 7%.
Ebonite is a dark brown or black material. Dielectric, lends itself well to all types of mechanical processing, is not hygroscopic, does not absorb gases, is resistant to the action of acids and alkalis, swells in carbon disulfide (CS 2) and liquid hydrocarbons. At 70 - 80 ° C it softens. Above 200 О С it is charred without melting. It is very flammable, and therefore is increasingly being replaced by other materials.
To obtain ebonite, the mass fraction of sulfur in the mixture with rubber must be at least 15%, but it can reach 34%.
Ebonite is used for the manufacture of electrical products, battery cans, containers for storing acids and alkalis.
| Topic or topic section | P. |
| Alcadienes - definition and classification | |
| Cumulated double bond alkadienes | |
| Allen, his physical properties | |
| Allen's electronic structure | |
| Allen's spatial structure | |
| Allen chemical properties. Water connection. Keto-enol tautomerism | |
| Attachment of other polar molecules to the allene | |
| Isolated alkadienes. Attachment reactions of non-polar and polar molecules to them. | |
| Ionic hydrogenation of unsymmetrical isolated alkadienes. Kursanov's reaction - Parnes. Selectivity in this reaction | |
| Conjugated alkadienes. Divinyl. Its electronic structure. | |
| Spatial structure of divinyl. | |
| The addition of non-polar (H2, Cl 2, Br 2 and I 2) and polar molecules to conjugated dienes at positions 1 - 4 and 1 - 2. Selectivity in this reaction | |
| Reaction of divinyl with hydrogen | |
| Reaction of isoprene with bromine | |
| Dependence of the number of reaction products of the addition of non-polar molecules on the presence or absence of symmetry in the structure of conjugated dienes | |
| Dependence of the number of products of the addition reaction of polar molecules on the structure of conjugated dienes | |
| Reaction of divinyl with hydrogen chloride | |
| Reaction of isoprene with water | |
| Polymerization of conjugated alkadienes | |
| Obtaining non-stereoregular butadiene rubber | |
| Getting stereoregular isoprene rubber | |
| Ziegler-Natta catalysts | |
| Chloroprene production method, its polymerization and vulcanization | |
| Vulcanization of chloroprene rubber | |
| Chloroprene Rubber Properties and Applications | |
| Methods for producing 1,3-butadiene | |
| Physical properties of 1,3-butadiene | |
| The method of obtaining divinyl from ethyl alcohol according to S.V. Lebedev | |
| Two-stage method for producing divinyl by dehydrogenation of ethanol and dehydration of a mixture of ethanol and ethanal | |
| Method for producing divinyl from butane-butylene fraction of associated petroleum gases | |
| Methods for producing isoprene | |
| "Dioxane" method for producing isoprene from 2-methylpropene and two moles of methanal | |
| Method for producing isoprene by dehydrogenation of 2-methylbutane | |
| Method for producing isoprene according to Favorsky from acetone and acetylene by hydrogenation of 2-methyl-3-butyn-2-ol obtained in the first stage | |
| Physical and Chemical properties isoprene | |
| Reaction of isoprene with maleic anhydride - Diels-Alder reaction | |
| Vulcanization of rubbers - obtaining rubber and ebonite | |
| Application of rubber | |
| Performance properties of ebonite and its application | |
| Content |
It might be helpful to read:
- Free online ebook library;
- Free online ebook library;
- Why are sellers unwilling to sell?;
- How do you know if you're good at selling?;
- The problem of reading books: arguments from fiction;
- Effective VKontakte advertising;
- Memento mori: how to come to terms with the fact that everyone you love will die Normal topic come to terms;
- The myth of overcoming difficulties;