Brovary asbestos in bags A6K-30, 5-57 (asbestos crumble), bottle, DTDM dithiodimorpholine, rubber, ATSEID plates

Brovary asbestos in bags A6K-30, 5-57 (asbestos crumble), bottle, DTDM dithiodimorpholine, rubber, ATSEID plates
 
Asbestos is the collective name for a number of fine-fibrous minerals from the class of silicates, which in nature form aggregates consisting of the finest flexible fibers. It is used in a wide variety of areas, such as construction, automotive and rocket science. Asbestos is now considered a major health and safety hazard.

It is a Category 1 carcinogen according to the IARC classification.
There are two main types of asbestos - chrysotile asbestos and amphibole asbestos.

     Chrysotile asbestos (white asbestos) is a mineral of the serpentine group, the chemical formula 3MgO•2SiO2•2H2O is magnesium hydrosilicate, structurally related to layered silicates. Due to the incommensurability of the tetrahedral and octahedral layers, stresses arise in the serpentine structure, which are compensated by bending the T-O packets, which usually leads to their “corrugation”, however, in the case of chrysotile, the direction of the bend is preserved and such layers twist into tubes with an outer diameter of about 200 angstroms (20 nm). Chrysotile-asbestos is resistant to alkaline media, decomposes in acids with the formation of amorphous silica. Elementary chrysotile crystals are the thinnest tubes-fibrils with a diameter of hundredths of microns. In practice, chrysotile is divided into bundles of fibers with a diameter of 10...100 microns, the tensile strength of which is 600...800 MPa, which is comparable to the best grades of steel. This type of asbestos is widespread in Russia.
     Amphibole asbestos is a complex hydrosilicate. Similar in physical and mechanical properties to chrysotile-asbestos, but has significant differences from it in the crystal structure. The fibrous structure of tremolite is associated with its crystal structure: the structure is ribbon and represents double chains of silicon-oxygen tetrahedra, in which individual chains are weakly bound by magnesium and calcium cations. Weak structural bonds break easily, but the amphibole fibers themselves are highly resistant in neutral and acidic environments. Amphibole asbestos have poor performance characteristics compared to chrysotile asbestos, so they are used much less often and where resistance to acids is required. Amphiboles have straight needle-like fibers - due to the fragility of these structures, they form particles, the inhalation of which is a carcinogenic factor. Therefore, this type of asbestos is forbidden to be used in the countries of the European Union, in which this type of asbestos was previously widely used.
Asbestos is also distinguished by the orientation of the fibers in the minerals: parallel-fibrous and entangled-fibrous. Depending on the impurities of the compounds of iron, calcium, manganese, there is also a different color of asbestos, so hornblende and augite asbestos are white, gray, brown, reddish-brown, almost black; chrysotile - golden yellow, silvery white, greenish, bluish and bluish black. For example: Ural asbestos is pure greenish, Altai asbestos is golden and greenish yellow. Altai and Ural serpentine asbestos reach 0.2 meters along the length of the fibers, Richmond asbestos (America) - up to 1 meter.
Asbestos materials began to be widely distributed in the world in the 1930s, and after the Second World War, their distribution increased many times over. If in the 1930s 300 thousand tons of asbestos were mined annually in the world, then in 1945 production increased to 750 thousand tons, and five years later it reached 1.3 million tons. doubled from 2.2 million tons to 4.7 million tons.
In 1980, the first protests against asbestos began. By 1985, its production decreased by 400 thousand tons per year, and by the beginning of the 2000s it had fallen to 2 million tons annually.
Currently, chrysotile asbestos is used in the world industry.
Chrysotile is part of more than three thousand products in various fields of technology.
Chrysotile is used in the production of:

     roofing, wall products (asbestos-cement flat and corrugated sheets, foam concrete);
     pipes (chrysotile cement pressure and non-pressure pipes of various diameters);
     front plates;
     asbestos technical and heat-insulating products (fabrics, cords, cardboard, filters, friction products, brake bands, paronite, etc.);
     fixers of the protective layer of concrete for the installation of tunnels, sealants;
     rubber materials, bricks;
     for the preparation of mastics, sealants, lining compounds, organosilicate coatings, drilling and grouting slurries, asphalt concrete mixtures, the preparation of adhesive mixtures and putties, mortars, repair and restoration compounds.
Butyl rubber (BK, indzhey-butyl, polysar-butyl, socabutyl, esso-butyl) is a copolymer of isobutylene with a small (1-5% wt.) amount of isoprene, which is obtained by cationic copolymerization of isobutylene and isoprene in the presence of Friedel-Crafts catalysts
Butyl rubber was first synthesized by a group of scientists from Exxon Research and Engineering Co. under the direction of W. J. Spark and R. M. Thomas In 1937.
Butyl rubber production technology
Butyl rubber is obtained in suspenzia and in solution.
In the slurry process, the heterophase copolymerization of isobutylene and isoprene is carried out in the presence of aluminum trichloride in methyl chloride or ethyl chloride at temperatures from minus 95 to minus 100°C.
In the solution process, homogeneous copolymerization of isobutylene and isoprene is carried out in the presence of a protonated complex of organohalogenated compounds in a hydrocarbon solvent at a temperature of minus 50 to minus 60°C. The solution technology for obtaining butyl rubber was developed in the USSR and introduced in 1982.
Technological properties of butyl rubber
The isobutylene nature of butyl rubber causes its low gas and moisture permeability. In terms of gas impermeability, it surpasses all known rubbers, with the exception of thiokol, which is explained by the large number of steric hindrances in the form of methyl groups and the low mobility of the polymer macromolecular chain due to the small number of double bonds.
Tendency to crystallize
Butyl rubber retains its amorphous structure over a wide temperature range and crystallizes only at high degrees of stretching (up to 500%).
Production (dyeing) of rubber compounds based on butyl rubber, their calendering, extrusion and molding are carried out on conventional equipment. In this case, it is desirable to allocate separate lines or units of equipment for the processing of butyl rubber.
Features of processing BC

     butyl rubber does not covulcanize into general purpose rubbers due to the strong difference in vulcanization activity;
     technologically, butyl rubber is combined with ethylene-propylene rubbers, halogenated butyl rubbers, chloroprene rubbers, polyisobutylene, polyethylene, polypropylene;
     plasticized only at a temperature of +170-180°C in a rubber mixer in the presence of peptizers;
     has a lower affinity for carbon black compared to highly unsaturated rubbers;
     has good adhesiveness;
     has a tendency to cold flow.

Vulcanizing systems of rubbers based on BR
Vulcanization of BR is usually carried out with sulfur using thiazole, thiuram and dithiocarbamate accelerators or ultraaccelerators.
Vulcanization can be carried out with dioximes and dinitroso compounds in the presence of oxidizing agents such as PbO2, as well as with polymethylolphenol resins in the presence of metal chlorides, for example SnCl2, or halogenated polymers such as polychloroprene.
Reinforcing fillers of butyl rubbers are technical carbons, as well as mineral fillers with a regular arrangement of OH groups in the lattice, such as kaolin, talc, silicon dioxide. Plasticizers for butyl rubbers are paraffinic, naphthenic and aromatic oils.
With an increase in the degree of filling and a decrease in the amount of plasticizers, the gas impermeability of vulcanizates increases.
Ethylene propylene rubber additives are used to improve cohesive properties, increase the rate of vulcanization, improve frost resistance and light resistance.
Application
Rubbers based on butyl rubber are used:

     in the tire industry - automobile inner tubes and the sealed layer of tubeless tires, cooking chambers and diaphragms of dormator-vulcanizers;
     in the medical industry - corks and other products for capping drugs;
     in the food industry;
     in the electrical industry.

Butyl rubber is a component of solid rocket fuel.
Dithiodimorpholine (DTDM) is a white powder with a yellowish or grayish tinge. It is used as a raw material in the production of tires and rubber products. Dithiodimorpholine is an accelerator and curing agent.
Properties
Dithiodimorpholine is soluble in benzene, acetone, alcohol. Does not dissolve in water. The introduction of DTDM into the rubber compound increases its resistance to vulcanization and slows down the aging process. The powder does not change the shade of white rubbers, does not fade over time. The accelerator is especially effective in mixtures based on synthetic stereoregular rubbers SKI-3 and SKD in combination with sulfenamides. Together with TMLM in butyl rubbers and nitrile butadiene rubbers, it makes it possible to obtain vulcanizates with low values of residual compression strain.
Application
The introduction of dithiodimorpholine into the rubber compound requires a reduction in the amount of sulfur. In formulations based on natural rubber with the addition of active furnace blacks, the content of the accelerator is about 1.0–2.0 wt. h. In mixtures with N-cyclohexyl-2-bezthiazolsulphenamide - from 0.25 to 1.0 wt. h.
Safety requirements
Dithiodimorpholine has low toxicity. May cause irritation of mucous membranes if inhaled. Dosing of the accelerator should be done in a respirator, goggles, overalls. The dusty mixture of DTDM is explosive. It is necessary to comply with fire safety requirements at the work site.
Dithiodimorpholine (DTDM) is a white powder with a melting point of 174-176 0C and a density of 1.36 g/cm3. Let's well dissolve in dichloroethane, carbon tetrachloride, chloroform, benzene, ether. Handling hazard: combustible.
N'-dithiodimorpholine (DTDM) canIt cannot be used alone or together with sulfur. The joint introduction of 2% DTDM by weight of rubber allows you to reduce the sulfur content in the rubber mixture to 0.25-0.50% by weight of rubber. The resulting rubbers are characterized by a higher resistance to aging and a lower tendency to premature vulcanization. DTDM does not change the color of rubber and does not fade, which is especially important for rubber compounds based on butyl rubber, since sulfur is poorly soluble in butyl rubber, it fades strongly, degrading the quality of products.
N'-dithiodimorpholine (DTDM) is also used in compounds based on rubbers SKD, SKI-3, SKN. It is especially effective with sulfenamides in mixtures of SKD and SKI-3 rubbers.
Dosage in mixtures based on natural rubber with active furnace blacks - 1.0 - 2.0 wt. hours, and when using N-cyclohexyl-2-benzothiazolesulfenamide - 0.25 - 1.0 wt. h. In rubber compounds intended for casting, it has also become widespread in combination with thiuram and sulfenamide.
In contrast to thiuram, the vulcanization process with the introduction of DTDM is much slower.
Heat resistance is the same as thiuram, DTDM does not give.
An additional difference from thiuram is that it is more environmentally friendly.
Rubbers are natural or synthetic elastomers characterized by elasticity, water resistance and electrical insulating properties; from which rubber and ebonites are obtained by vulcanization.
Industrial Application
The most widespread use of rubbers is the production of rubbers for automobile, aircraft and bicycle tires.
Special rubbers are made from rubber for a huge variety of seals for the purposes of heat, sound, air and waterproofing of demountable elements of buildings, in sanitary and ventilation technology, in hydraulic, pneumatic and vacuum technology.
By pressing a mass consisting of rubber, asbestos and powder fillers, paronite is obtained - a sheet material for the manufacture of gasket products with high heat resistance, operating in various environments - water and steam with a pressure of up to 5 MN / m2 (50 atm) and a temperature of up to 450 ° WITH; oil and oil products at temperatures of 200–400°C and pressures of 7–4 mN/m2, respectively; liquid and gaseous oxygen, ethyl alcohol, etc. The high sealing properties of paronite are due to the fact that its yield strength, which is about 320 MPa, is achieved by tightening the joint with bolts or studs, while the paronite fills all the bumps, shells, cracks and other defects sealing surfaces and seals the joint. Paronite is not a corrosive material and lends itself well to mechanical processing, which makes it easy to produce gaskets of any configuration that do not lose their performance in any climatic conditions - neither in areas with a temperate climate, nor in tropical and desert climatic conditions, nor in extreme conditions. North. The high heat resistance of paronite allows it to be used in internal combustion engines.
By reinforcing the paronite with a metal mesh to improve the mechanical properties, ferronite is obtained.
Rubbers are used for electrical insulation, the production of medical devices and contraceptives.
In rocket technology, synthetic rubbers are used as a polymer base in the manufacture of solid rocket fuel, in which they play the role of fuel, and saltpeter powder (potassium or ammonium) or ammonium perchlorate is used as an oxidizing agent.