Ninety years ago today, on February 28, 1935 (January 25, 1935 in the lunar calendar), the research group of Wallace Carothers of DuPont Company in the United States synthesized nylon for the first time. Born on April 27, 1896 in Burlington, Iowa, USA, and died on April 29, 1937 in Philadelphia, USA. Around us, all kinds of items made of nylon materials can be seen everywhere. Nylon bags, nylon cloth, nylon socks, nylon mosquito nets, nylon curtains and more, you name it. However, the invention of nylon can be regarded as an accidental invention. In the early 1930s, there was a chemist named Carothers in America. He first worked as a teacher of organic chemistry at the famous Harvard University, and at the age of 33, he was hired at the research institute of DuPont Chemical Industries as the head of the basic department. Carothers is full of imagination and diligence, and his assiduous research spirit is well known. One day in the summer of 1932, Carothers arrived in his laboratory early in his usual white coat. Carefully, he noticed that there were milky white filaments stuck to the tip of a glass rod, which was formed by the residue that had not been washed off in the last experiment. The scientist was very curious and pulled the filament hard, and found that it was not only stretched, but also very strong. At this time, a thought flashed in Carothers' mind: Is it possible to reuse the polyamide that had failed in previous experiments? So he took out this compound, which was likely to be disposed of as waste, heated it again, and then tore it into thin filaments to see if it could make rayon. Then Carothers conducted in-depth research on a series of polyester and polyamide compounds. After many comparisons, he selected polyamide 66, which he first synthesized from hexanediamine and adipic acid on February 28, 1935 (the first 6 represents the number of carbon atoms in the diamine, and the second 6 represents the number of carbon atoms in the diacid). number of carbon atoms). This polyamide is insoluble in common solvents and has a melting point of 263oC, which is higher than the commonly used ironing temperature. The drawn fiber has the appearance and luster of silk, and is also close to natural silk in structure and properties. Its abrasion resistance and strength exceed any fiber at that time. Considering its properties and manufacturing cost, it is the best choice among the known polyamides. In 1935, Carothers successfully turned this idea into reality, and rayon called "nylon" was finally successfully invented. DuPont immediately organized its efforts to produce nylon and quickly occupied the market. On October 27, 1938, it was officially announced that the world's first synthetic fiber was born, and the synthetic fiber polyamide 66 was named Nylon. Nylon later became "the general term for all polyamides synthesized from coal, air, water or other substances, with abrasion resistance and protein-like chemical structure" in English. Since entering DuPont, Carothers has been aggressive, continuous exploration, and successfully obtained patents for several other inventions, among which the synthesis of artificial rubber is particularly eye-catching. In order to develop this kind of rubber material, which was very scarce at that time, he devoted himself to the systematic research of low molecular composite and polymer synthesis, reaching the point of forgetting to eat and sleep. Despite many failures, the tenacious inventor was not at all discouraged. Hard work paid off. He synthesized artificial rubber in less than a year, and the trade name was neoprene. The appearance of neoprene rubber is also inseparable from the molecular distillation method invented by Karolsas, which reacts in vacuum.