Polyester and acrylic fiber were produced after vinylon
Vinylon is the trade name of polyvinyl formal fiber, also known as vinylon (vinylon), or transliterated into vinylon. Its performance is close to cotton, so it is also called artificial cotton.
Polyvinyl formal fiber is a product of polyvinyl alcohol polymer treated with formaldehyde acetalization.
Generally speaking, polymers are produced by polymerization of monomers. However, polyvinyl alcohol is not polymerized from vinyl alcohol. Because vinyl alcohol is very unstable, it will rearrange its molecules and turn into acetaldehyde. Therefore, vinyl alcohol actually does not exist.
In 1924, German chemists W.O. Hermann and W. Hachnel prepared polyvinyl alcohol by dissolving polyvinyl acetate in methanol and adding sodium hydroxide. Produced after alcoholysis:
Polyvinyl acetate is produced by the polymerization of vinyl acetate. Vinyl acetate can be made from acetylene as raw material, and acetic acid is first produced. As early as 1881, the Russian chemist Kucherov used acetylene to prepare acetaldehyde and then oxidized it to produce acetic acid, and then reacted acetylene and acetic acid in the presence of the catalyst zinc acetate to produce vinyl acetate:
So polyvinyl alcohol is actually The above is made from acetylene as raw material. As early as 1931, the Germans had mastered the technology of using polyvinyl alcohol to produce fibers and films, which was sold under the trade name Synthofil. But then it was discovered that this fiber is extremely hydrophilic. Clothes made from this fiber cannot be washed with water if they are dirty, otherwise the original clothes will not be found; if you put the clothes in hot water , the clothes cannot be found because they have been dissolved by the water. This is mainly due to the fact that the long-chain molecules of polyvinyl alcohol have many hydroxyl groups (—OH) that have a strong affinity for water:
By 1939, Ichiro Sakurada (1904-1986), a professor of chemistry at Kyoto University, Japan ), a doctor from the Institute of Applied Chemistry of Kyoto University, Japan, Korean Lee Seung-gi (1905-?), and Dr. Masahide Yano of Japan's Jongyeon Textile Research Institute jointly researched and proposed the heat treatment and acetalization treatment methods, which made it become Shinichi Yamada, a fiber with good heat resistance and water solubility. The history of world inventions and discoveries. Translated by Wang Guowen et al. Beijing: Patent Literature Press, 1989. . The so-called heat treatment is to heat the fiber at 220~270℃ for 5~10 minutes to reduce the shrinkage of the fiber and improve the hot water resistance of the fiber. Acetalization uses the aldehyde group (-CHO) in aldehyde molecules such as formaldehyde and benzaldehyde to condense into water with the hydroxyl group (-OH) in the polyvinyl alcohol molecule to remove the hydrophilic -OH in the polyethylene molecule. Formaldehyde is generally used, and the product is polyvinyl formal fiber, usually called polyvinyl acetal fiber, omitting the word "A".
Acetalization treatment cannot remove all hydroxyl groups. When the degree of acetalization is very high, the performance of the fiber is not ideal. Therefore, the degree of acetalization is generally controlled to only 30%~35%. In other words, there are still a considerable number of hydrophilic hydroxyl groups (—OH) on the long chain of fiber macromolecules. Therefore, vinylon has higher hygroscopicity than other synthetic fibers.
In 1941-1942, Japan's Narabuchi Textile Research Institute and Kurashiki Rayon Company built intermediate experimental production facilities with an annual output of 150 tons and 60 tons respectively. They were later shelved due to World War II and were not realized until the war. industrialization.
Because the hygroscopicity of vinylon is similar to that of cotton, it is often used as a substitute for cotton and blended with cotton to make cotton muslin, poplin, khaki, corduroy, etc. Vinyl products are strong, durable and cheap. They are used in industry as canvas, filter cloth, etc.
With the production of vinylon, polyester and acrylic fiber were produced one after another. Polyester is the trade name for polyester fiber.
Before making polyamide fiber, Carlos used sebacic acid and ethylene glycol to perform condensation polymerization to obtain polyester. He found that it had the performance of spinning fiber, but it was easy to hydrolyze and It had a low melting point and was easily soluble in organic solvents, so it was abandoned and turned to the development of polyamide.
J.R. Whinfield, a British chemist who participated in the development of synthetic fibers by Carrozes, realized that in order to be used as a fiber for industrial textiles, the polymer must have a high melting point and It is resistant to chemical and solvent effects and has a high degree of molecular linear structure.
After returning to the UK, he and chemist J.T. Dickson selected ethylene glycol (CH2OHCH2OH) and para (position) phthalic acid (HOOCC6H4COOH) for condensation polymerization, and achieved success in 1939. Para-phthalic acid has a more linear symmetric molecular structure than ortho- or meta-phthalic acid, and the presence of benzene nuclei in the polymer molecules can increase the melting point of the product.
With the outbreak of World War II, the British supply department believed that this new polymer might become a military material, and asked the Chemical Laboratory of the Scientific and Industrial Research Department to continue research to produce laboratory quantities. In 1943, the sample was sent to Imperial Chemical Industries, which developed it into a textile material. It built a factory in Wilton, Yarks, and produced it under the trade name terylene. The American DuPont Company purchased the patent and built a factory in Kinston, North Carolina, for production. Construction started in March 1953. The trade name was dacron. We translated it from the transliteration to "really good". .
In industrial production, dimethyl terephthalate and ethylene glycol are used for transesterification reaction. The so-called transesterification reaction, that is, the exchange of methyl groups (—CH3) in dimethyl terephthalate molecules between ethylene glycol and dimethyl terephthalate, is carried out using catalysts such as zinc acetate:
Toluene Ethylene dicarboxylate is a colorless and transparent polyester monomer. After polymerization reaction, polyethylene terephthalate is formed, either into solid particles or directly spun into a melt.
Terephthalic acid and ethylene glycol are directly esterified and then polymerized, which has not been utilized in industrial production for a long time. This is because terephthalic acid has a high melting point and low solubility in water, making it difficult to purify. At the same time, the reaction speed of phthalic acid and ethylene glycol is slow, and the reaction between solid and liquid is difficult to control.
Polyester has better thermal stability than nylon. The biggest feature of polyester as a clothing fiber is its good wrinkle resistance and shape retention. The clothes made are crisp and wrinkle-free, with beautiful appearance and good strength. The impact resistance is 4 times higher than that of nylon. However, the disadvantage is that it has low hygroscopicity, making clothes woven with it feel stuffy and easily charged with static electricity, making it easy to be stained.
After polyester, acrylic fiber appeared. Acrylic fiber is the trade name of polyacrylonitrile fiber in my country. The properties of acrylic fiber are very similar to wool, so it is also known as "synthetic wool" and "artificial wool".
Acrylic fiber was successfully researched by the American DuPont Company in the early 1940s. In 1942, experimental samples were sent to the U.S. government for military use. In 1945, it was experimentally produced. In 1948, the use of orlon was announced as a product. Name, industrial production started in 1950. Acrylic is a polymer of acrylonitrile.
Acrylonitrile is a colorless, flammable liquid that is toxic and can be produced from petrochemical processing products acetylene or ethylene.
This fiber has particularly superior sun resistance and was first used to make awnings, car hoods, etc. Later, it was discovered that its properties are very similar to wool and was used to blend with wool.
The acrylic fiber seen on the market is not a polymer polymerized from one monomer, acrylonitrile. It is usually polymerized from three monomers, which are vinyl chloride ( CH2=CCl), vinylene chloride (CH2=C=Cl2) and vinylene cyanide (CH2=C=(CN)2). Added chlorine to the composition makes it flame resistant.