A synthetic or natural substance with elastic properties, electrical insulation characteristics and water resistance is called rubber. Vulcanization of such a substance through reactions involving certain chemical elements or under the influence of ionizing radiation leads to the formation of rubber.
How did rubber come about?
The chronicle of the appearance of rubber in the European countries of rubber began when Columbus brought strange treasures from the new continent in 1493. Among them was a surprisingly bouncing ball made by local natives from the milky juice of a hevea tree. The Indians called this juice “kauchu” (from “kau” - a tree, “chu” - tears, crying) and used in ritual rites. The name was fixed at the Spanish royal court. However, in Europe, the existence of unusual material was forgotten until the 18th century.
The general interest in rubber arose only after the French navigator S. Kondamin in 1738 presented to the scientists from the Paris Academy of Sciences a certain elastic material, samples of products from it, its description and production methods. S. Condamine brought these things from an expedition to South America. There, the natives made various household items from the resin of special trees. Such material is called "rubber", from lat. resina - "resin". It was from then on that the search began for ways to use this substance.
What is rubber?
However, there is little in common between the name resina and the concept by which we perceive this material today. After all, wood resin is only raw material for rubber.
The vulcanization of rubber makes it possible to significantly improve its quality, make it more elastic, strong and durable. It is this process that allows you to get many varieties of rubbers for technical, technological and domestic purposes.
Rubber value
Today , rubber is most widely used in rubber production. Modern industry makes various types for automobile, aviation, bicycle tires. It is used in the manufacture of all kinds of seals for detachable elements in hydraulic, pneumatic and vacuum devices.
The product obtained during the vulcanization of rubber with sulfur and other chemical elements is used for electrical insulation, in the production of medical and laboratory devices and devices. In addition, various rubbers are used for the manufacture of conveyor belts operating under heavy loads, anti-corrosion coatings of boilers and pipes, various types of glue and thin-walled high-strength small items. Synthesis of artificial rubber made it possible to create some types of solid rocket fuel, where this material plays the role of fuel.
What is vulcanization of rubber and what does it give?
The vulcanization process involves the mixing of rubber, sulfur and other substances in the required proportions. They are subjected to heat treatment. When rubber is heated with a sulfur agent, the molecules of this substance are bonded to each other with sulfur bonds. Some of their groups form a single three-dimensional spatial grid.
The composition of rubber includes a large amount of hydrocarbon polyisoprene (C5H8) n, proteins, amino acids, fatty acids, salts of certain metals and other impurities.
In the molecule of natural rubber, up to 40 thousand elementary units can be present, it does not dissolve in water, but it is perfectly split in organic solvents. However, if rubber is capable of almost completely dissolving in gasoline, then the rubber in it will only swell.
Vulcanization of this material helps to reduce the plastic properties of rubber, optimizes the degree of its swelling and solubility in direct contact with organic solvents.
The process of vulcanization of rubber provides the material obtained with more durable properties. Rubber made using this technology is able to maintain elasticity over a wide temperature range. At the same time, violations of the technological process in the form of an increase in the addition of sulfur lead to the appearance of hardness of the material and the loss of elastic abilities. The result is a completely different substance called ebonite. Before the advent of modern types of plastics, ebonite was considered one of the best insulating materials.
Alternative techniques
Nevertheless, science, as you know, does not stand still. Other vulcanizing agents are known today, but sulfur is still the highest priority. To accelerate the vulcanization of rubber, 2-mercaptobenzthiazole and some of its derivatives are used. As alternative methods, ionizing radiation is carried out using some organic peroxides.
Usually, with any type of vulcanization, a mixture of rubber and various additives is used as the feedstock, giving the rubber the required properties or improving its quality. The addition of fillers, for example, soot and chalk, helps to reduce the cost of the resulting material.
As a result of the technological process, the rubber vulcanization product acquires high strength and good elasticity. That is why various types of natural and synthetic rubbers are used as raw materials for the manufacture of rubber.
Prospects for further development
Thanks to the development of synthetic rubber production technologies, rubber production has completely ceased to depend on natural material. Nevertheless, modern technologies have not supplanted the potential of natural resources. Today, the share of natural rubber consumption for industrial purposes is about 30%.
The unique qualities of a natural resource ensure the indispensability of rubber. It is necessary in the manufacture of large-sized rubber products, for example, in the manufacture of tires for special equipment. The most famous tire manufacturers in the world use mixtures of natural and synthetic rubbers in their technologies. That is why the largest percentage of the use of natural raw materials falls on the tire industry.