Synthesis and production of nylon
Nylon is the first synthetic fiber, which is made by scientists in America and Britain. We also call it nylon. It is a polyamide compound, and their molecular structures all contain the same amide bond, so it is also called polyamide fiber.
Traditionally, in order to distinguish the varieties of polyamide fibers, some Arabic numerals, such as polyamide 6, polyamide 66 or nylon 66, are often added after polyamide or nylon to indicate the number of carbon atoms contained in the monomer molecules that produce such fibers. For example, polyamide 6 or nylon 6 is polymerized from caprolactam monomer with 6 carbon atoms, and polyamide 66 or nylon 66 is polymerized from hexamethylenediamine H2N(CH2)6NH2 with 6 carbon atoms and adipic acid HOOC(CH2)4COOH with 6 carbon atoms.
Nylon 66 was synthesized by American and British scientists headed by American chemist Carlos at 1935 in DuPont's laboratory.
They didn't start by making synthetic fibers. 1928 Carrozes is employed by DuPont. At that time, Germany had a heated debate on the theory of polymer compounds put forward by organic chemist Taudinger. Karozes supported staudinger's viewpoint and was determined to prove the correctness of this theory through experiments, so he polymerized various substances. In 1930, Carothers used ethylene glycol HO(CH2)2OH and sebacic acid HOOC(CH2)8COOH for polycondensation to obtain polyester. When Karozes' colleague Hill took the molten polyester out of the reactor with a stirring rod, he found that it stretched like silk, and this fibrous filament could continue to stretch after cooling, and the stretching length could reach several times. After cold drawing, the strength and elasticity of the fiber are greatly increased. This phenomenon makes them realize that this characteristic may have practical value, and this molten polymer may be used to spin fibers. They also studied a series of polyester compounds. Because the polyesters studied at that time were all polymers formed by condensation polymerization of fatty acids and fatty alcohols, they were easy to hydrolyze, their melting point was lower than 100℃, and they were soluble in organic solvents, so they were not suitable for textile fibers. So they turned to the study of polyamide compounds.
In a few years, Karozes and his colleagues prepared a variety of polyamides from different polycondensation reactions of diamines and diacids, and their properties were not ideal. 1935 they synthesized polyamide from pentanediamine and sebacic acid. The results show that the strength and elasticity of the fiber made of this polyamide are higher than that of silk, and it is not easy to absorb water and dissolve, but the melting point is still low, and the raw materials used are expensive, which is still not suitable for commercial production. After condensation polymerization of hexamethylenediamine and adipic acid into polyamide, it was also placed in the storage cabinet and was selected after cold tensile test. It is insoluble in common solvents and its melting point is as high as 263℃.
After this polyamide was determined as a material for manufacturing synthetic fibers, it could not be put into industrial production because of raw material problems. Because the raw materials for making this polymer are hexamethylenediamine and adipic acid, it was only made in the laboratory at that time. 1936, R. Williams, a chemist from DuPont, created a new catalyst to convert phenol into adipic acid, and hexamethylenediamine was prepared from adipic acid. In this way, the raw material is only phenol, which can come from coal tar.
193810/0 On October 27th, Justin, chairman of DuPont, announced the establishment of a large-scale production plant in Seaford, Delaware. The factory started operation in June 1939+0.
During production, the polyamide melt is evenly and quantitatively extruded from the spinneret hole by the metering pump to form a mucilage trickle, which is cooled and solidified into filaments in the air. This creates a new melt spinning method for synthetic fibers, which is different from the solution spinning method used in artificial fibers. Solution spinning method is to dissolve fiber-forming polymer in an appropriate solvent to make a viscous spinning solution, and then squeeze the viscous solution out of the spinneret quantitatively and evenly, and solidify it into filaments in another solution or air. Melt spinning method is relatively simple, of course, it is necessary that the synthetic fiber polymer will not decompose at high temperature and has sufficient stability.
The product of nylon 66 was originally a brush. 1February, 939, stockings woven from it were exhibited at the Golden Gate International Expo in the United States. 1939 exhibited at new york World Commodities Fair in April; 1939 10 went on sale at the headquarters of DuPont, Delaware, USA on124, causing a sensation. The chaotic situation at that time forced the public security organs to dispatch police to maintain order. 1May, 940, sold all over the United States, regarded as a rare treasure, scrambling to buy.
It was not until 1945 that nylon 66 turned to weaving parachutes, aircraft tire cords, military uniforms and other military products. After World War II, it developed very rapidly, and products appeared in countless ways, from stockings and clothes to carpets and fishing nets.
The outstanding properties of nylon are high strength, good elasticity and good wear resistance. Its strength is 2~3 times that of cotton, its wear resistance is 10 times that of cotton and 20 times that of wool. It is also corrosion-resistant, moth-eaten, light in weight, but poor in shape retention and easy to deform; Heat resistance is also poor, and light resistance is not good enough.
Dupont started the basic research of polymer compounds, which lasted for several years and cost 22 million dollars. 230 scientific and technical personnel participated in this work. In the end, we got the products that benefit mankind and got rich returns. Unfortunately, Carlo Zeiss, the inventor of nylon 66, didn't see its practical application. Suffering from mental depression, he committed suicide by drinking lemon juice mixed with potassium cyanide in a hotel room in Philadelphia, USA on April 29, 1937, at the age of 4 1 year.
At the same time that nylon 66 appeared in the United States, in 1937, German chemists headed by schrack synthesized nylon 6, which is a polymer of caprolactam. 1939 put into industrial production, 194 1 put into mass production.
At the same time, Russia produced nylon 7, a heptalactam polymer with one more carbon atom than caprolactam. Nylon 10 10 produced in France was polymerized by decylamine H2n (CH2) 10 and sebacic acid HOOC(CH2)8COOH with 10 carbon atoms. According to the national conditions of China, China scientists also made nylon 10 10 from castor oil. At present, the main varieties of polyamide fibers produced in China are nylon 66 and nylon 6.
Synthesis and production of polyester fiber
After the synthesis of polyamide fiber, the road of synthetic fiber was opened up and a series of synthetic fibers such as polyester were popularized.
Esters are compounds of organic carboxylic acids and alcohols, and polyesters are polymers of esters with ester groups in the molecular structure.
Before making polyamide fiber, Karozes used sebacic acid and ethylene glycol for polycondensation to obtain polyester. It is found that it has the performance of spinning fiber, but it is abandoned because of its easy hydrolysis, low melting point and easy solubility in organic solvents, and polyamide is developed instead.
Winfeld, a British chemist, participated in the development of synthetic fibers by Carotz. He realized that to become a polymer of industrial textile fibers, it must have a high melting point, be able to resist the influence of chemicals and solvents, and have a highly linear structure. After he returned to England, he and the chemist Dixon chose ethylene glycol (CH2OHCH2OH) and terephthalic acid (HOOCC6H4COOH) for polycondensation, and 1939 succeeded. Terephthalic acid has a more linear and symmetrical structure than phthalic acid, and the existence of benzene rings in polymer molecules can improve the melting point of products.
1943, the British Imperial Chemical Industry Company set up a factory in Jacques Wilton with the trade name "Dacron". 1953, DuPont Company of the United States obtained a patent and set up a factory for production. The trade name "Dacron" was transliterated as "Dacron" and became popular.
China began to study the production of polyester monomer in the 1950s, and began to produce it in the early 1970s with the trade name of polyester.
The thermal stability of polyester is better than nylon. As a clothing fiber, polyester is characterized by good wrinkle resistance and shape retention. The clothes made of polyester are crisp and wrinkle-free, with beautiful appearance and good strength, and the impact strength is four times higher than that of nylon. But the disadvantage is that the hygroscopicity is small, and the clothes woven with it feel sultry, easy to take static electricity and easy to be polluted.
Synthesis and production of acrylic fiber
After polyester, acrylic fiber appeared. Acrylic fiber was successfully developed by DuPont in the early 1940s. 1942, the experimental samples were sent to the us government for military use; 1945, acrylic fiber was put into trial production; And officially produced under the trade name (Olun) on 1948.
It is a polymer of acrylonitrile (CH2CHCN).
This kind of fiber has special and superior light fastness. Originally used to make awnings, car awnings, etc. Later, it was found that its performance was very similar to wool, and it was blended with wool as a wool substitute, so it was named synthetic wool or artificial wool.
The acrylic fiber seen in the market is not polymerized by acrylonitrile, but usually polymerized by three monomers. They are vinyl chloride (CH2CCl), vinyl chloride (CH2 ccl 2) and cyanoethylene CH2CC(CN)2. Adding chlorine to the composition can prevent fire.
Acrylic fiber production in China began in the mid-1960s. At present, the output and quality of acrylic fiber have been greatly improved.
Synthesis and production of vinylon
Another synthetic fiber is vinylon or vinylon for short. This word was put forward by Japanese chemists, because they developed vinylon successfully.
Vinylon is the trade name of polyvinyl acetal, which is the product of polyvinyl acetal.
Polyvinyl alcohol does not polymerize with vinyl alcohol (CH2CHOH) monomer. Because vinyl alcohol is very unstable, it will rearrange itself into acetaldehyde.
In order to obtain polyvinyl alcohol, polyvinyl acetate was dissolved in methanol and sodium hydroxide was added for alcoholysis.
Polyvinyl acetate is a polymer of vinyl acetate. Vinyl acetate is made of acetylene.
1924, German chemists Herman and Heller first made polyvinyl alcohol, 193 1 year, and they mastered the technology of spinning fibers with polyethylene. However, clothes spun from this fiber can't be washed with water when they are dirty, but they will disappear after washing because they are soluble in water. This is because there are many hydrophilic hydroxyl groups (-OH) in the long chain of polyvinyl alcohol, so it can only be used in special occasions, such as surgical sutures for surgeons.
Until 1939, Sakurada Ichiro, a professor in the Department of Chemistry of Kyoto University, Lee Seung Gi, a Korean graduate student in the Institute of Applied Chemistry of Kyoto University, and Dr. Yano Jiang Ying of Zhongyuan Textile Institute jointly studied and proposed the acetalization method to make it a fiber with good water resistance.
Acetalization is treated with formaldehyde to condense formaldehyde with hydroxyl groups on long-chain molecules of polyvinyl alcohol.
Acetalization treatment can not "eat up" all hydroxyl groups. At the same time, it is found that when the acetalization degree is very high, the performance of the fiber is not ideal, and its acetalization degree is generally 30% ~ 35%, so a certain amount of hydrophilic hydroxyl groups remain in the long chain of the fiber, which makes vinylon have higher hygroscopicity than other synthetic fibers.
194 1~ 1942, Japan Zhongyuan Textile Company and Cangfu Silk Company built pilot plants with an annual output of 150 tons and 60 tons respectively, which were shelved after World War II and were not industrialized until after the war.
China began to research, design, manufacture and install the first vinylon factory in 1957, and it was officially completed and put into operation in 1964.
Vinylon has good seawater corrosion resistance and is suitable for fishing nets and ropes for offshore operation. Because vinylon is similar to cotton in hygroscopicity and cotton fiber in appearance, it is also called artificial cotton. It is blended with cotton and used to sew underwear, sheets, quilts, tablecloths and curtains.
Polypropylene and polyvinyl chloride are both plastics and synthetic fibers, also known as polypropylene fibers and chlorine fibers.