Rubber is a natural and synthetic elastomer. It has good water resistance, elasticity and electrical insulation properties. As you can see, it has many positive characteristics that are used in various fields. Rubber production is currently one of the most sought-after types of business, as it is now used on a huge scale.

Production of natural rubber + video how they do it

Of course, some share of natural rubber is found in various plants, but, of course, not in all. Not everyone knows, but even dandelions contain a small amount of rubber, but it must be properly extracted.

The substance extracted in plants is mixed with hydrocarbons and also their marching ones. The most interesting thing is that natural rubber practically does not have the ability to dissolve anywhere. It does not swell and does not interact in any way with substances such as gasoline, acetone, water, alcohol. But while the rubber is at room temperature, it begins to age. That is, it shrinks and becomes completely unusable. All this happens because, at room temperature, oxygen begins to attach to the rubber. Of course, with the aging of rubber, its elasticity decreases and, accordingly, its strength also becomes much less. And at high temperatures (about 200 degrees), rubber begins to decompose. When it combines with sulfur or other sulfur solutions, it gives it great elasticity and strength. Since natural rubber does not have any harmful substances, it is quite easily and quickly processed into rubber. It is from such raw materials that sufficiently strong and high-quality rubber can be obtained, which can be used in a wide variety of fields.

Natural rubber has a large number of positive characteristics; it is often used for. More than 60% of all rubber is used in this production.

Synthetic rubber production + video how they do it

Synthetic rubber has a wide variety of additives, without which it will not have all that is necessary for normal operation with it. Synthetic rubber is most often produced at specialized enterprises or factories, since it is there that everything necessary for such production is available. The very first rubber was produced a long time ago.

Polybutadiene was used to make rubber. At first it seemed to all people that it was wonderful and suitable for use. But, after a while, it was noticed that this species has too low mechanical properties. For use, and long-term use, it is absolutely not suitable. Of course, synthetic rubber is made only from chemical materials, since it is absolutely impossible to obtain high-quality material only from harmless materials.

Synthetic rubber is very popular, and it is natural that its production is popular. This is all due to the fact that the production of synthetic rubber is much faster than natural rubber. Since a large number of equipment and various technologies are used for the synthetic look, which simplify the entire production.

A detailed video of how synthetic is made:

There are a large number of different rubbers, but this only applies to its chemical composition. Quite often, any kind of rubber is used mainly in the automotive industry. Because it's popular there. It is very easy to make an excellent tire for a car from it. Rubber, as mentioned earlier, is a completely unpretentious material that can withstand any external impact. It can also be used to produce various rubber medicines. As you can see, any rubber is considered completely harmless.

Department of Chemical Technology of Fuel.

Course work at the rate

"General chemical technology"

Manufacture of synthetic rubber.

Completed:

2nd year student

gr.MAXStart-08-1

Shaferov Yu.A

Checked:

PhD chem. Sciences

Raskulova T.V.

Angarsk 2011

1. Introduction

2. Basic properties of general purpose rubbers

2.1 Comparison of the properties of the main types of rubbers

3. Technology and production

3.1 Types of polymerization

4. Styrene-butadiene rubbers

4.1 Physical characteristics of emulsion styrene-butadiene rubbers with different content of styrene units

4.2 Properties of low-temperature emulsion methylstyrene-butadiene rubber vulcanizers containing about 23% styrene units

5. Reactor-polymerizer

6. Conclusion

6. References

1. Introduction

Currently, there is a wide variety of rubbers on the market, according to their properties and characteristics, they can be divided into two large segments: general purpose rubbers and special purpose rubbers.

A number of events influenced the invention of synthetic rubber: the industrial revolution, advances in engine building, two world wars, the growing demand for rubber and the scarcity of natural rubber provoked a worldwide demand for elastomers. Synthetic rubbers have become a necessary alternative to natural rubber and have added additional properties to products.

Currently, there is a wide variety of rubbers on the market in terms of properties and characteristics. But in the most general form, they can be divided into two large segments: general purpose rubbers and special purpose rubbers.

Table 1

General purpose rubbers are used in products where the very nature of the rubber is important and there are no special requirements to the finished product. Special purpose rubbers have a narrower scope and are used to give a rubber product (tires, belts, shoe soles, etc.) a given property, for example, wear resistance, oil resistance, frost resistance, increased grip on wet roads, etc. Most often, one rubber combines several properties, so the selection of rubbers in the formulation of a rubber product for certain areas is a thorough work of technologists.

Special rubbers are used in the rubber industry in much smaller quantities compared to general purpose rubbers. The areas of application for general purpose and special purpose rubbers also differ. Therefore, in this review, only general-purpose rubbers, which have similar methods of production, processing and use, will be considered in detail.

The properties of synthetic rubbers determine their applications. The creation of a rubber product formulation is accompanied by the selection of various types of rubbers, fillers, softeners, etc. The correct combination of all components in the formulation makes it possible to obtain a rubber product with desired properties.

2.Basic properties of general purpose rubbers

Styrene butadiene rubber

Styrene butadiene rubber has an excellent combination of functional properties in various applications. This rubber is considered the best general purpose rubber due to its excellent abrasion resistance properties and high fill percentage. With an increase in the content of styrene units (α-methylstyrene) in the copolymer, the elasticity of rubber decreases, frost resistance deteriorates, but strength indicators increase. A characteristic feature of styrene-butadiene (α-methylstyrene) rubbers is the low tensile strength of unfilled vulcanizates. These rubbers have a higher glass transition temperature than natural rubber and are inferior to natural rubber in frost resistance. An important advantage of styrene-butadiene rubber over natural rubber is less tendency to cracking, higher wear resistance, vapor and water resistance, better resistance to thermal, ozone and light aging. Rubbers with a high content of styrene have good dielectric properties (the amount of styrene in a mixture of monomers is 50 wt.% and more).

Polybutadiene rubber

Most of the polybutadiene rubber currently produced is of the 1,4-cis type, but some have a mixed unit structure. Being an unsaturated rubber, it vulcanizes easily with sulfur. Polybutadiene rubber has excellent resistance to low temperatures and to abrasion. But at the same time, it does not have high tensile strength and is usually filled with reinforcing additives. It also has lower tensile strength, poor processing and poor traction compared to natural rubber. Therefore, in the formulations of rubber products, it is mixed with natural rubber or styrene-butadiene rubber.

Polybutadiene rubbers are used in large quantities in blends with other elastomers to impart good hysteresis properties and abrasion resistance. Blends of polybutadiene with styrene butadiene or natural rubbers are widely used in car and truck tires to improve crack resistance. In addition, polybutadiene rubber is used as a modifier in mixtures with other elastomers to improve cold-resistant properties, resistance to heat aging, abrasion and cracking.

Butyl rubber

Butyl rubber has a unique ability to retain air, which makes it an undisputed priority in the tire industry for the production of tubes and diaphragms. Automotive tubes made of butyl rubber maintain initial air pressure 8-10 times longer than similar tubes made of natural rubber, which increases tire life by at least 10-18% compared to natural rubber. Rubber is resistant to ozone and has good resistance to polar solvents, aqueous acids and oxidizing agents. It has good animal resistance and vegetable oil but butyl rubber is not resistant to mineral oils.

The tensile strength of butyl rubber is slightly less than natural rubber, but at high temperatures this is the same for both rubbers. Abrasion resistance is good when the rubber is thoroughly filled (as well as compression set), but the resilience is still very low. The disadvantages of butyl rubber include its low vulcanization rate, poor adhesion to metals, poor compatibility with certain ingredients, low elasticity at normal temperatures, and high heat generation during repeated deformations.

Some of these significant disadvantages of butyl rubber (such as low cure rate, which prevents its use in mixtures with other rubbers, low adhesion to many materials, especially metals) are eliminated by a partial change in the chemical nature of the polymer. For example, by introducing a small amount of halogen atoms into rubber macromolecules. Bromobutyl rubber (from 1 to 3.5 wt.% bromine) is processed and mixed with ingredients in the same way as butyl rubber. But at the same time, bromobutyl rubber vulcanizes much faster than butyl rubber. The vulcanization rate of bromobutyl rubber is comparable to the vulcanization rate of natural, butadiene-styrene and other rubbers, which makes it possible to use it in mixtures with these elastomers. Other halogenated butyl rubbers have similar properties, for example, chlorobutyl rubber (1.1 - 1.3 wt.% chlorine). However, the vulcanization rate and properties of chlorobutyl rubber vulcanizates are somewhat lower than those of bromobutyl rubber.

Ethylene propylene rubbers

Ethylene propylene rubbers are the lightest rubbers, which have a density of 0.86 to 0.87. The properties depend on the content and variation of ethylene units in the copolymer units. Ethylene propylene rubber does not contain double bonds in the molecule, colorless, has excellent resistance to heat, light, oxygen and ozone. For saturated ethylene-propylene rubbers, peroxide vulcanization is used. Ethylene-propylene-diene rubber, which contains partial unsaturation of bonds, allows vulcanization with sulfur. It is slightly less resistant to aging than EPDM.

The rich nature of the ethylene-propylene copolymer affects the properties of rubbers based on this rubber. The resistance of these rubbers to heat and aging is much better than that of styrene-butadiene and natural rubbers. The finished rubber products also have excellent resistance to inorganic or highly polar liquids such as acids, alkalis and alcohols. The properties of rubber based on this type of rubber do not change after keeping it for 15 days at 25C in 75% and 90% sulfuric acid and 30% nitric acid. On the other hand, resistance to aliphatic, aromatic or chlorinated hydrocarbons is quite low.

All types of EPDM are filled with reinforcing fillers such as carbon black to give good mechanical properties. The electrical, insulating and dielectric properties of pure EPDM are extraordinary, but also depend on the choice of filler ingredients. Their elastic properties are better than many synthetic rubbers, but they do not reach the level of natural rubber and styrene butadiene rubber. These rubbers have two significant drawbacks. They cannot be mixed with other simple rubbers and are not resistant to oil.

Rubbers - a group of substances of natural or synthetic origin, used in the production of rubber, which are distinguished by such properties: elasticity, electrical insulation, water resistance. The source of raw materials for natural rubbers is the milky sap of a number of plants that secrete latex (it is a white liquid with special properties).

By isolating this juice from plants, the process of its coagulation is stimulated in order to obtain a solid material. Rubber mainly consists of polyisoprene (91-96%). At the same time, latex, which serves as a raw material for it, is a fairly common component of plants. It can be found in representatives of different botanical groups of plants.

Rubber is found in different parts of the plant, and on this basis they (that is, plants) are classified into groups:
- latex - the substance accumulates in the milky juice;
- parenchymal - in stems and roots;
- chlorenchyma - in leaves and young green shoots.
- herbaceous latex plants of the Asteraceae family (Krym-saghyz, kok-saghyz, etc.), where rubber accumulates in underground organs in a small concentration, are not used in industry.

What is synthetic rubber? It is made from synthetic polymer compounds that are vulcanized to become rubber. In particular, in Russia, such industries are engaged in Krasnoyarsk and Tolyatti.

Synthetic rubber is a high-polymer compound obtained from butadiene, isoprene, styrene, neoprene, isobutylene, chloroprene, acrylic acid nitrile, which are polymerized or copolymerized. The resulting material has similar properties with natural. Thus, its molecules are also long and partially branched chains of many thousands of monomers. The average molecular weight is typically in the hundreds of thousands to millions. During polymerization, some chains are linked to each other in many places by means of double bonds. Thus, the vulcanized substance is chemically a high-molecular spatial network with the corresponding physicochemical properties.

There are many types of rubber, which are classified according to the type of monomers from which they are made (butadiene, isoprene). It is also possible to classify according to the presence of special atoms or functional groups (for example, polysulfide, urethane).

As for synthetic rubbers, they have an additional classification:
- according to the content of fillers (unfilled and filled);
– final form (liquid, solid, powder);
- molecular weight.
For example, a number of synthetic latexes look like aqueous dispersions, while others are thermoplastic elastomers.

There are synthetic rubbers that do not have unsaturated bonds in the initial state (silicone rubber, polyisobutylene). To vulcanize them, organic amines, peroxides and other compounds are used. As a result, you can get a substance that will even be better than natural in origin.

Depending on the application, synthetic materials are divided into two groups: general and special rubbers. The first category includes substances that have excellent elasticity, strength and other characteristics that allow the material to be used for the manufacture of objects of various directions. Special rubbers are created to provide special material properties, so they are used to a limited extent, only for individual products.

Common rubbers include:
- butadiene;
- butadiene styrene;
- isoprene.

Special rubbers:
- ethylene propylene;
- urethane;
- butyl rubbers;
— fluororubbers;
- chloroprene, etc.

Rubber is used for the production of automobile and bicycle tires, aircraft chassis, and an electrically insulating coating is made from it. Also, this material is actively used in the manufacture of medical devices.

1. Natural rubber

Natural rubber has been around for thousands of years. Scientists are finding fossils that contain the remains of rubber plants dating back millions of years BC. For the first time, representatives of civilization learned about such material 500 years ago, when they discovered America. And rubber became really in demand only recently, in the 30s of the XIX century. Then the Indians actively sold shoes and bottles made of rubber to white people.

In 1839, Charles Goodyear synthesized rubber by inventing the vulcanization process. He heated rubber with sulfur and found that the material improved its properties. As soon as the rubber was discovered, it began to be actively used. So, until 1919, more than 40,000 types of products using this material were sold on the market.

Natural rubber plants

In the Tupi-Guarani language, the word "rubber" is derived from "kau" (tree) and "uchu" (to cry). It was the combination of these words that the Indians called the milky juice of hevea, which was the main rubber plant of that time. For convenience, in Europe they added one letter to the word "rubber", and it turned out "rubber". In Russia there are also plants containing milky juice - spurge, dandelion, wormwood.

But for industrial purposes, you can use only those plant materials that not only contain latex, but are also ready to give it away easily in large quantities. Brazilian hevea is such a raw material, rubber from which makes up 90-96% of the volumes used in the world.

Other sources of rubber are less pure as they contain resins and other impurities that need to be purified. For example, in a number of sapote trees, there is gutta-percha in rubber.

Rubber-bearing trees grow mainly in the equator zone, not moving away from it more than 10 ° to the south and north, that is, this is a belt 1300 km wide, which is called the “rubber belt”. It is here that such trees are grown for industrial purposes, and their raw materials are sent for sale around the world.

Physical and chemical properties of rubber

If we talk about natural rubber, then it has the following properties:
- an amorphous solid, which in some cases can be crystallized;
- in raw (or raw) form it is white, sometimes colorless;
- does not dissolve in most liquids, including water and alcohol, does not swell in them;
- swells only in similar substances (gasoline, ether, benzene, other aromatic hydrocarbons), gradually dissolving in them.

Rubber in solutions similar to itself can form colloidal solutions. They have found wide application in technology.

Natural rubber has a fairly homogeneous molecular structure, and this determines its unique physical and technological properties. Actually, due to such a unique structure, it can be processed with the formation of rubber.

Rubber is valued because of its elasticity or elasticity, that is, products made from this material are able to return to their original shape very quickly, as soon as the deformation forces cease to act. The elasticity of rubber is one of the best in its class. So, even if the product from it is stretched to 1000%, it will return to its original shape. For classical solids, this figure is 1%. At the same time, rubber has the same properties both in a heated and in a cooled state. But the material has a drawback - over time, it hardens and loses its properties.

If rubber is placed in liquid air (-195°C), then it will be hard and transparent, but in the temperature range of 0 ° - 10 °C, transparency and rigidity disappear. Under normal conditions (20 °C), the material acquires its famous properties - it is soft, translucent, quite elastic. Above 50°C, rubber begins to become sticky and plastic. If the heating is continued to 80 °C, at this stage elasticity is lost, and at 120 °C the rubber completely becomes a resin-like liquid. If it is cooled, it will not look like the original substance. 200-250 °C is exactly the temperature at which rubber irreversibly decomposes into gaseous and liquid substances.

Rubber has pronounced dielectric properties, it is practically impervious to water and gas. Moreover, as mentioned, this material is insoluble in water, acids and alkalis, and in alcohol - only in a very small amount. But gasoline, chloroform and carbon disulfide are able to dissolve this substance, first causing it to swell. Oxidation of rubber by chemical means is easy, but with air it is rather difficult. Rubber has an extremely low thermal conductivity - 100 less than steel.

The advantage of rubber is that it is not only elastic, but also has high ductility. And this means that this material under the influence of external forces will acquire and maintain the desired shape. During heating, as well as mechanical processing, this property is especially manifested. Thus, rubber can be considered a plastoelastic substance.

Another property that rubber has is when it is stretched or cooled. This is the crystallization of a substance that occurs over a long period of time. During this process, heat is released, which heats the natural substance at the moment of stretching. Rubber has small crystals without a characteristic shape and clear edges.

If the rubber is cooled to -70 ° C, it will cease to be plastic and acquire some of the properties of glass.

Thus, like most polymers, rubber exists in three states, depending on temperature - highly elastic, viscous and glassy. Under normal conditions, rubber is highly elastic.

Despite the resistance to acids, rubber reacts quite easily with simple substances - oxygen, halogens, sulfur, hydrogen, which is explained by the presence of unsaturated bonds in it. To emphasize the similar chemical properties of this material, it is worth transferring it to a colloidal solution, where the interaction is enhanced.

Chemical reactions do not go unnoticed for the physical properties of matter. So, the characteristics of strength, solubility, elasticity change. For example, oxygen and ozone, which interact with rubber even at room temperature, cause the breakdown of large polymeric molecules of the substance into smaller ones, which leads to a loss of strength of the material. In addition, it is due to oxidation with oxygen that rubber passes from a solid to a plastic state.

The chemical structure of natural rubber and its composition

Natural rubber is a polymeric unsaturated hydrocarbon with a large number of double bonds. Its universal chemical formula is as follows: (C5H8)n, where n is the degree of polymerization, which has values ​​of 1000-3000). As can be seen, the monomer of natural rubber is isoprene.

The source of natural rubber is the milky sap of various tropical plants (for example, Brazilian hevea). They also contain gutta-percha, which is also an isoprene polymer, but with a different chemical structure. If the rubber molecule were not atomically thin, it could be seen with a microscope because it is very long. And if it is also stretched as much as possible, then it will be a zigzag-like large line, which is due to the type of carbon bonds.

Due to the fact that in isoprene there is an alternation of single and double bonds, the particles of the molecule can rotate exclusively around single bonds. Due to such vibrations, the molecule is constantly bent, even at rest it has close ends.

And the fact that rubber molecules have close ends at rest determines the elasticity of the substance. When a material is stretched, its molecules are stretched in the same direction. As soon as the deformation effect ends, the chain becomes curved again.

Thus, the molecules of natural rubber are some kind of almost round springs that stretch very strongly and increase in size when the ends are separated. A number of researchers believe that this polymer chain is a springy helix.

If a chemical analysis of natural rubber is carried out, it will be found that the substance consists only of hydrogen and carbon, which allows it to be attributed to hydrocarbons. This is confirmed by the primary formula of rubber. It used to be C5H8. Over time, scientists realized that such a simple spelling cannot reflect the complexity of the structure of the molecule, because the molecular weight of individual units reaches half a million or more. Thus, natural rubber is a natural polymer of isoprene, namely cis-1,4-polyisoprene.

Natural rubber is a collection of many thousands of chemical micromolecules that are firmly connected to each other, so they can only carry out vibrational-rotational movements inside the macromolecule. These micromolecules are particles of isoprene, the simplest hydrocarbon that forms rubber. But there are other polymers based on the isoprene monomer, although they do not have similar properties of elasticity and plasticity. What is it connected with?

In rubber, like in other polymeric molecules, the atoms are arranged in a chain, but it is not a continuous straight line, but constantly wraps, forming, as it were, a ball. Under the influence of a mechanical force, the material is stretched due to the alignment of individual sections of this coil. As soon as the impact ends, the molecule tends to take its natural position and returns back to the coil. And only too much zeal allows you to straighten the material so much that its chains of molecules not only do not go back, but break, deforming this area.

2. Synthetic rubber

If in America rubber has been used at least in some form for 500 years, then in Russia things are different. Since there are no natural raw materials in the country, initially there was no production of the material. And there were no supplies of ready-made rubber. But in 1927, namely on December 30, Soviet scientists obtained synthetic divinyl rubber by sodium polymerization of 1,3-butadiene. This experience prompted the industrial production of 1,3-butadiene, from which they began to make rubber.

Butadiene is synthesized from ordinary ethanol. This happens by dehydrogenation and dehydration of this molecule simultaneously. To achieve this, alcohol is turned into steam and passed over catalysts that start both reactions at once. Then the resulting butadiene is purified from the starting materials, products of side reactions and, having achieved complete purification of the fraction, it is used for the synthesis of rubber.

How to make monomers, which perfectly exist in this state, begin to polymerize? First, the desired carbon atoms must be excited, that is, brought to a state in which double bonds begin to break to form a polymer chain. To do this, you must either use a strong catalyst or spend a lot of energy.

The use of a catalyst for the polymerization of rubber is quite advantageous, because this material is not lost during the reaction, but only excites carbon atoms. At the end of the polymerization, the catalyst remains in the same amount as it was at the beginning. S. V. Lebedev, developing the synthesis of artificial rubber, used metallic sodium as a similar substance, following the example of A. A. Krakau, who used this catalyst for the polymerization of other unsaturated hydrocarbons.

At the same time, the polymerization of butadiene has an advantage - as a result, the end product is only finished rubber without other by-products, since during the reaction the monomers combine into a polymer as a whole, without the formation of additional substances.

Main types of synthetic rubber

There are many types of synthetic rubber. Even the mentioned first material, synthesized on the basis of butadiene, is produced in the form of stereoregular and nonstereoregular rubber. The first is our use as a starting material for car tires, as it is more durable and wear resistant than natural rubber. And the non-stereoregular type is used in the production of ebonite, rubber, resistant to aggressive liquids, etc.

Scientists are constantly synthesizing artificial rubbers, which in all respects are a more perfect material than natural ones. For example, excellent substances in their properties are copolymers of butadiene and styrene, acrylonitrile. During polymerization, the chain is built up by alternating butadiene with the corresponding second monomer. This allows you to achieve special properties that are not inherent in classical rubbers.

So, styrene-butadiene rubber has excellent wear resistance, so this material is in great demand in the production of rubber for cars, conveyor belts, and shoe soles.

Nitrile butadiene rubber does not deteriorate under the influence of oil and gasoline, so it is used in the manufacture of oil seals.

When butadiene is copolymerized with vinylpyridines (in particular, with 2-methyl-5-vinylpyridine), vinylpyridine rubber is obtained. It is made for the production of rubber of a special property. It is resistant to gasoline and oil, durable when used in cold weather, adheres well to any material. This type of latex is used as an impregnation for tire cord.

In Russia, they are also engaged in the manufacture of classic synthetic rubber, the properties of which are very similar to those of a natural material. When this rubber is vulcanized, rubber is obtained, the strength, plasticity and elasticity of which do not differ much from those of a natural product. Such synthetic rubber is also used for the manufacture of car tires, shoes, conveyor belts, various medical products are made from it.

As for rubbers, in which special properties are determined by heterogeneous atoms or functional groups, the following subspecies are worth noting here:
1. Silicone rubbers. They are used in the manufacture of medical products, in particular, tubes for blood transfusion, artificial heart valves, various cables, wires.
2. Polyurethane rubbers. They are used as a basis for wear-resistant rubbers.
3. Fluorinated rubbers. They are distinguished by the ability to operate at high temperatures, even more than 200 ° C, when ordinary rubber is completely destroyed.
4. Chloroprene rubbers. They are made from chloroprene, as this monomer is more resistant to the effects of gasoline, oil and oxidizing agents.

There are also other types of rubber - this is foamed, and inorganic (polyphosphonitrile chloride) rubber, and others.

The main use of both natural and synthetic rubber is the production of rubber of the appropriate type. This is due to the fact that rubber in its pure form is a rather brittle and less elastic material, which cannot be said about its vulcanized product.

So, the production of rubber from rubber has the following steps:
1. Creation of a raw material base:
— hanging of rubbers and components of rubber;
— plasticization of rubbers;
– coating of fabric with rubber, calendering, extrusion;
- cutting the resulting rubberized fabric, as well as sheets, picking up finished products.
2. Vulcanization, the purpose of which is to bring the rubber in the product from a semi-finished state to a finished one.

So, to make a rubber product, rubber is mixed with various fillers (for example, soot) and sulfur, a mold is filled with these components and heated. Due to the increase in temperature, the unsaturated bonds of rubber become less strong, so sulfur is introduced to them, cross-linking the macromolecules with each other into a network with disulfide bridges. Thus, a huge whole molecule is obtained, formed not on a plane, but in space. It is much better than pure rubber in all properties.

Now such polymer becomes more reliable. For example, rubber is no longer soluble in gasoline, unlike rubber, which is slowly destroyed by this solvent.

If it is necessary to obtain ebonite, an excess of sulfur must be added during vulcanization, which will contribute to the formation of more bonds and lead to hardness and loss of elasticity. In the old days, ebonite was one of the best insulating materials.

Rubber is much more elastic and stronger than classic rubber. In addition, it is not so much subject to temperature fluctuations, the effects of gases, mechanical destruction, the effects of electric current, summer heat, and the action of various chemicals. In addition, vulcanized rubber has a high degree of sliding friction on a dry surface and a low degree of sliding friction on a wet surface.

In order to carry out the formation of rubber more quickly, so-called vulcanization accelerators are used in factories. They allow you to make the conversion process faster, without marriage, using less raw materials. As a rule, such substances are magnesium oxide, lead, and other inorganic salts. In addition, organic substances are used - dithiocarbamates, thiurams, xanthates and other derivatives that have an accelerating effect.

But the accelerators themselves will not work if they are not activated. This is done by adding zinc oxide.

The next mandatory component of rubber is antioxidants. They prevent it from aging.

Fillers are added to improve strength characteristics, abrasion resistance and to increase wear resistance. By the name, you can also understand that due to these substances it is possible to increase the total volume of raw materials by making as much rubber as possible out of a smaller amount of rubber, which will make it a more accessible and cheaper material. Fillers are chalk, talc, gypsum, barium sulfate, quartz sand, carbon black.

The last component of quality rubber are plasticizers or softeners. They are designed to make the substance less viscous with a large number of fillers. Due to plasticizers, rubber becomes more resistant to various dynamic influences, in particular, to abrasion. The main list of plasticizers is as follows:
- fuel oil;
- paraffins;
- tar;
- rosin;
- stearic and oleic acids, etc.

The properties of rubber, in particular, resistance to various organic solvents, strength, are directly dependent on its composition. So, if it is made from natural rubber, it will be resistant to oil, gasoline, have good elasticity, wear resistance. But such material will be destroyed under the action of aggressive substances. If you need a more wear-resistant rubber, make it from styrene-butadiene rubber. The use of isoprene rubber makes it possible to obtain an elastic product that will be resistant even when strongly stretched. But the use of chloroprene raw materials contributes to the creation of rubber that is resistant to oxidation by oxygen.

So, in Russia, they have been dealing with rubber for a long time, since the time of the empire, when in 1860 the Triangle plant was opened in St. Petersburg (renamed in 1922 into the Red Triangle). Then the enterprises "Rubber", "Explorer", "Bogatyr" and others were opened. Years of development have made it possible to introduce technologies for the production of various types of rubber that provide the required properties.

The use of rubber in the production of various products

Rubber is widely used in industry. But as a rule, this raw material is used for the production of rubber, which, in turn, is used for the manufacture of various finished products. Rubber is in demand in the following areas of production:
- insulation for wires;
- car tires;
- shoes;
– special clothing;
- artificial leather;
- medical products;
- military parts and components.

Rubber has more elasticity than rubber, but less ductility. This is partly due to the fact that this is not a simple substance, but a mixture of rubber with various components.

Most of all, the automotive and engineering industries need rubber. The more rubberized various parts in any mechanisms, the more comfortable they are in maintenance, reliable and durable. It takes thousands of different types of rubber parts to build one car, and the number is growing.

Types of rubber, their application

The simplest classification divides rubber into monolithic and porous. So, the first one is made of butadiene rubber, due to which it is very wear-resistant. For example, if you use such rubber for the sole, it will last 2-3 times longer than special sole leather. In addition, such a material will be less prone to rupture when stretched, will not let water through even in excess, and will not deteriorate under the influence of moisture.

Of course, in rubber shoes, frosts will be more noticeable, and it will not retain heat as much as leather. Also, this material is impervious to air and steam, but this does not detract from its performance.

Non-porous rubber is divided into leather-like, transparent and plantar. It is used to make soles, heels, heels, overlays and other shoe components.

But porous rubber is used to make soles and other parts of summer shoes.

Leather-like rubber is used to make the bottom of the shoe. To reduce the thickness of the material to a few millimeters, a large amount of styrene is used in the production of such rubber (about 80-85% of the total polymer composition), which increases the hardness of the future rubber.

Due to the unique composition of leather-like rubber, its properties are similar to ordinary leather. It is just as plastic and hard, so it can be used to make shoes of any kind and shape. In the manufacture of such rubber can be painted in any color. Leather-like rubber is quite wear-resistant, has high resistance to frequent bending. This is the best option for budget shoes.

Shoes with leather-like soles are usually worn for 179-252 days if the toe does not crumble earlier. But when purchasing such products, it should be borne in mind that it has a number of hygienic drawbacks, namely, minimal hygroscopicity and breathability, as well as high thermal conductivity.

There are three types of leather-like rubber:
— non-porous structure and density 1.28 g/cm3;
— porous structure and density 0.8-0.95 g/cm3;
— porous structure, fibrous filler and density up to 1.15 g/cm3.

The last type of porous rubber is also called "leather". They have properties almost identical to natural leather. Due to the addition of fibers, rubber has a slightly best performance thermal insulation. In addition, this material is more elastic, lighter, has a more pleasant appearance. Such rubber is used for the manufacture of heels and soles of summer and spring shoes, which are attached with an adhesive method.

Transparent rubber is another natural rubber product that has a translucent appearance. Its main difference is high wear resistance and hardness. Transparent rubber is used in the manufacture of footwear for the manufacture of molded soles, the running side of which has a strong corrugation. One commonly used type of transparent rubber is styronip, which has a high rubber content. This material is very resistant to repeated bending, so it is used for the production of shoes that are assembled using the adhesive method.

Porous rubber is characterized in that it contains pores, which can be 20-80% of the total volume of the material. Due to this, high product flexibility, elasticity, softness, and other depreciation properties are achieved. But these types of rubber shrink over time, and they are also easy to get dirty (in particular, in the toe of the shoe) during impacts on various surfaces. To increase the hardness of porous rubber, polystyrene resin is added to it.

Now such types of porous rubber as vulcanite and porocrepe are actively used and produced. The first material contains a number of fibrous fillers that increase the wear resistance of the product and improve thermal insulation properties. The second is used to provide increased strength and elasticity, in addition, it has a pleasant color. Porous rubber has found wide application in the manufacture of winter and demi-season shoes.

made from synthetic alcohol based on products of oil and gas processing, timber industry, calcium carbide. Tires and various rubber products are made from rubber.

Main production centers for synthetic rubber:

Voronezh;

Efremov;

Yaroslavl;

Krasnoyarsk;

Sterlitamak;

Tolyatti and others.

The largest tire factories:

. Moscow,

Nizhnekamsk,

Ural,

Kirovsky,

Barnaul,

. Voronezh and others.

Manufacture of synthetic resins and plastics. The raw materials for the production of plastics - polyethylene, polypropylene, polystyrene, thermoplastics are products of oil and gas processing, coal, associated gas, and partially wood.

Enterprises are:

In Moscow;

Vladimir;

St. Petersburg;

Volgograd;

Nizhny Tagil;

Tyumen and others.

Manufacture of chemical fibers and threads. Chemical fibers and threads are divided into artificial, obtained as a result of chemical processing of natural polymers (cellulose), and synthetic, produced from synthetic polymers (the raw materials are products of oil and gas processing. Placement factors are fuel and water.

Production centers:

Balakovo;

Barnaul;

Krasnoyarsk and others.

The production of chemical fibers and threads is of great importance for Russia as a country with a developed textile industry, but at the same time with an extremely limited natural raw material base for the production of fabrics.

The microbiological industry produces:

feed yeast;

Amino acids;

vitamins;

enzyme preparations;

antibiotics;

Preparations for the protection of plants from pests and diseases, etc.

Production is based on the use of hydrocarbon raw materials and raw materials of plant origin, processed with the help of microorganisms. This production is characterized by high material consumption, the raw material factor is the leading one in placement. The main centers of the microbiological industry:

Nizhny Novgorod;

Krasnoyarsk;

Arkhangelsk;

Volgograd.

4. Main enterprises pharmaceutical industry located in Moscow, Moscow region, St. Petersburg. Currently, a number of domestic drugs cannot compete with foreign ones, which are imported into Russia on a massive scale. This economically undermines the domestic production of medicines.

Synthetic rubbers are polymers that can be processed into rubber by vulcanization. Their appearance was preceded by a shortage of natural rubber and a growing demand for elastomers. Currently, there is a huge number of brands of synthetic rubbers on the market with different properties and purposes. Conventionally, they can be divided into two large classes: rubbers for general and special purposes.

General purpose synthetic rubber is used in the production of automobile tires and parts, sealing rings and other consumer products. As a rule, general purpose rubbers combine a large number of properties, which makes them more versatile than special purpose rubbers. However, the narrow scope of this or that synthetic polymer is explained by the ideal balancing of its formulation in order to achieve the required properties.

Synthetic rubber is obtained by polymerization of monomers obtained from crude oil fractions. Depending on the reaction medium, four types of polymerization are distinguished: liquid-phase, emulsion, gas-phase and solution. Its properties directly depend on the method of rubber production. For example, styrene-butadiene synthetic rubber, which occupies more than 50% of the synthetic rubber market due to its introduction into the automotive industry, is produced by high-temperature emulsion polymerization. This method allows you to achieve optimal physical properties of a particular type of rubber products. The production of synthetic rubber directly depends on the monomers used: butadiene, styrene, isoprene, propylene, benzene, isoprene, ethylene. Their combination and method of polymerization determines the final properties of rubber, as well as its purpose.

Compared to natural rubber, its synthetic counterpart is a more profitable and promising material. First, it is more versatile. Modern production methods make it possible to obtain a material with optimal properties for a particular application. In addition, the production of synthetic rubbers is much cheaper.

In recent years, synthetic rubbers have found wide application not only in the automotive industry, but also in sound, heat, hydro and air insulation of buildings, as well as in the production of pneumatic, hydraulic, medical and vacuum equipment. In addition, this material is widely used in rocket science as a polymer base for the production of solid rocket fuel with ammonium nitrate powder as a filler.