|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
HISTORY OF TECHNOLOGY, TECHNOLOGY, OBJECTS AROUND US
Synthetic fibres. History of invention and production
Directory / The history of technology, technology, objects around us Synthetic fibers, Chemical fibers - textile fibers obtained from natural and synthetic organic polymers, as well as inorganic compounds.
For thousands of years, mankind has used for its needs natural fibers of plant (linen, cotton, hemp) and animal (wool, silk) origin. In addition, mineral materials, such as asbestos, were also used. Fabrics made from these fibers were used to make clothes, technical needs, etc. Due to the growth of the world's population, natural fibers have become scarce. That is why there was a need for their substitutes. The first attempt to obtain artificial silk was made in 1855 by the Frenchman Audemars on the basis of nitrocellulose. In 1884, the French engineer G. Chardonnay developed a method for obtaining artificial fiber - nitro silk, and since 1890 a wide production of artificial silk was organized using the nitrate method with the formation of threads using spinnerets. Especially effective was the work that began in the 90s of the XIX century. production of silk from viscose. Subsequently, this method was most widely used, and now viscose silk accounts for approximately 85% of the world's production of man-made fibers. In 1900, the world production of viscose silk amounted to 985 tons, in 1930 - about 200 thousand tons, and in 1950 the production of viscose silk reached almost 1600 thousand tons. In the 1920s, the production of acetate silk (from cellulose acetate) was mastered. In appearance, acetate silk is almost indistinguishable from natural silk. It is slightly hygroscopic and, unlike viscose silk, does not wrinkle. Acetate silk is widely used in electrical engineering as an insulating material. Later, a method was discovered for obtaining acetate fibers of extremely high strength (a cord with a cross section of 1 cm2 can withstand a load of 10 tons). Based on the progress of chemistry throughout the XNUMXth century. in the USSR, England, France, Italy, the USA, Japan and other countries, a powerful industry of artificial fiber was created. On the eve of World War I, only 11 thousand tons of artificial fiber were produced worldwide, and 25 years later, the production of artificial fiber pushed back the production of natural silk. If in 1927 the production of viscose and acetate silk was about 60 thousand tons, then in 1956 the world production of artificial - viscose and acetate - fibers exceeded 2 million tons. The difference between natural, artificial and synthetic fibers is as follows. Natural (natural) fiber is completely created by nature itself, artificial fiber is made by human hands, and synthetic fiber is created by man in chemical plants. In the synthesis of synthetic fibers from simpler substances, more complex high-molecular compounds are obtained, while artificial materials are formed due to the destruction of much more complex molecules (for example, fiber molecules in the production of methyl alcohol by dry distillation of wood). Nylon, the first synthetic fiber, was discovered in 1935 by the American chemist W. Carothers. Carothers first worked as an accountant, but later became interested in chemistry and enrolled at the University of Illinois. Already in the third year he was assigned to lecture on chemistry. In 1926, Harvard University elected him professor of organic chemistry. In 1928, a sharp turn took place in the fate of Carothers. The largest chemical concern "Dupont de Nemours" invited him to head the laboratory of organic chemistry. Ideal conditions were created for him: a large staff, the most modern equipment, freedom in choosing research topics. This was due to the fact that a year earlier the concern had adopted a strategy for theoretical research, believing that in the end they would bring significant practical benefits, and therefore profit. And so it happened. After three years of hard work, Carothers's laboratory, investigating the polymerization of monomers, achieves an outstanding success - a polymer of chloroprene is obtained. On the basis of it, in 1934, the DuPont concern began the industrial production of one of the first types of synthetic rubber - polychloroprene (neoprene), which, in terms of its qualities, can successfully replace the scarce natural rubber. However, Carothers considered the main goal of his research to be a synthetic substance that could be turned into fiber. Using the method of polycompensation, which he studied at Harvard University, in 1930 Carothers obtained a polyester as a result of the interaction of ethylene glycol and sebacic acid, which, as it turned out later, was easily drawn into fiber. This was already a great achievement. However, this substance could not have practical application, as it was easily softened by hot water. Further numerous attempts to obtain a commercial synthetic fiber were unsuccessful, and Carothers decided to stop working in this direction. The management of the concern agreed to close the program. However, the head of the chemical department opposed this outcome. With great difficulty, he persuaded Carothers to continue his research. Rethinking the results of his work in search of new ways to continue it, Carothers drew attention to the recently synthesized polymers containing amide groups in the molecule - polyamides. This choice proved to be extremely fruitful. Experiments have shown that certain polyamide resins, squeezed through a spinneret made from a thin medical syringe, form filaments from which fiber can be made. The use of new resins seemed very promising. After new experiments, Carothers and his assistants on February 28, 1935 received polyamide, from which it was possible to produce a strong, elastic, elastic, waterproof fiber. This resin, isolated by the reaction of hexamethylenediamine with adipic acid, followed by heating the resulting salt (AG) in vacuum, was named "polymer 66", since the initial products contained 6 carbon atoms. Since they worked on the creation of this polymer simultaneously in New York and London, the fiber from it was called "nylon" - after the initial letters of these cities. Textile specialists recognized it as suitable for the commercial production of yarn. Over the next two years, DuPont scientists and engineers developed processes for the production of polymer and nylon yarn intermediates in the laboratory and designed a pilot plant chemical plant. On February 16, 1937, nylon was patented. After many experimental cycles, in April 1937 fiber was obtained for an experimental batch of stockings. In July 1938, the construction of an experimental enterprise was completed. On April 29, 1937, three days after Carothers turned 41, he passed away by taking potassium cyanide. An outstanding researcher was haunted by the obsession that he did not succeed as a scientist. Nylon cost $6 million to develop, more than any other public use product. (For comparison, the United States spent $2,5 million to develop television.) Outwardly, nylon resembles natural silk and approaches it in chemical structure. However, in terms of its mechanical strength, nylon fiber is approximately three times superior to viscose silk, and natural - almost two times. DuPont has long guarded the secret of the nylon manufacturing process. And even she made the necessary equipment for this. Both employees and wholesalers of the goods necessarily gave a non-disclosure subscription for information relating to "nylon secrets". The first commercial product to hit the market was nylon bristle toothbrushes. Their release began in 1938. Nylon stockings were demonstrated in October 1939, and from the beginning of 1940, nylon fiber was produced in Wilmington, which was bought by knitting factories to make stockings. Thanks to the mutual agreement of trading companies, stockings from competing manufacturers appeared on the market on the same day: May 15, 1940. Mass production of nylon products began only after World War II, in 1946. And although many other polyamides (kapron, perlon, etc.) have appeared since then, nylon is still widely used in the textile industry. If in 1939 the world production of nylon was only 180 tons, then in 1953 it reached 110 thousand tons. Nylon plastic was used in the 50s to manufacture ship propellers for small and medium-sized ships. In the 40-50s of the XX century. other synthetic polyamide fibers also appeared. So, in the USSR, capron was the most common. The raw material for its production is cheap phenol, produced from coal tar. About 1 tons of resin can be obtained from 0,5 ton of phenol, and nylon can be made from it in an amount sufficient to make 20-25 thousand pairs of stockings. Kapron is also obtained from oil refining products. In 1953, for the first time in the world in the USSR, a polymerization reaction between ethylene and carbon tetrachloride was carried out on a pilot scale, and the initial product for the industrial production of enanth fiber was obtained. The scheme of its production was developed by a team of scientists led by A. N. Nesmeyanov. In terms of basic physical and mechanical properties, enanth not only was not inferior to other known polyamide fibers, but also in many respects surpassed nylon and nylon. In the 50-60s. of the last century, the production of polyester, polyacrylonitrile synthetic fibers began. Polyester fibers are formed from a melt of polyethylene terephthalate. They have excellent heat resistance, retaining 50% strength at 180°C, are flame retardant and weather resistant. Resistant to solvents and pests: moths, molds, etc. Polyester thread is used for the manufacture of conveyor belts, drive belts, ropes, sails, fishing nets, hoses, as the basis for tires. Monofilament is used for the production of mesh for paper machines, racket strings. In the textile industry, a thread made of polyester fibers is used to make knitwear, fabrics, etc. Lavsan belongs to polyester fibers. Polyacrylonitrile fibers are similar in properties to wool. They are resistant to acids, alkalis, solvents. They are used for the manufacture of outerwear, carpets, fabrics for suits. In a mixture with cotton and viscose fiber, polyacrylonitrile fibers are used to make linen, curtains, and tarpaulins. In the USSR, these fibers were produced under the trade name Nitron. Many synthetic fibers are made by forcing a polymer melt or solution through spinnerets 50 to 500 micrometers in diameter into a cold air chamber where the filaments solidify and become fibers. A continuously formed thread is wound on a bobbin. The acetate fibers are cured in hot air to evaporate the solvent, while the viscose fibers are cured in precipitation baths with special liquid reagents. The stretching of the fibers on the reels during formation is used in order for the chain polymer molecules to take on a clearer order. The properties of the fibers are influenced by various methods: by changing the extrusion speed, the composition and concentration of substances in the bath, by changing the temperature of the spinning solution, bath or air chamber, by varying the size of the die opening. An important characteristic of the strength properties of the fiber is the breaking length, at which the fiber breaks under its own gravity. For natural cotton fiber, it varies from 5 to 10 km, for acetate silk - from 12 to 14, for natural - from 30 to 35, for viscose fiber - up to 50 km. Fibers made of polyesters and polyamides have greater strength. So in nylon, the breaking length reaches 80 km. Synthetic fibers have replaced natural fibers in many areas. The total volume of their production is almost equal. Author: Pristinsky V.L.
▪ Printers
Artificial leather for touch emulation
15.04.2024 Petgugu Global cat litter
15.04.2024 The attractiveness of caring men
14.04.2024
▪ Military electronics with DNA marking ▪ Copolymers will increase HDD capacity by 5 times ▪ Cells increase in volume when tissues are bent ▪ Created a hybrid of man and sheep
▪ section of the site Stories from the life of radio amateurs. Selection of articles ▪ article Pedagogy. Lecture notes ▪ article How much air is on Earth? Detailed answer ▪ European olive article. Legends, cultivation, methods of application ▪ article Prefix for testing transistors. Encyclopedia of radio electronics and electrical engineering
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
We recommend interesting articles Section 
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page