尼龙Nylon

命名中的数字表示单体碳原子数：尼龙 66 的第一个 6 指二胺含 6 个碳、第二个 6 指二酸含 6 个碳；尼龙 6 由含 6 个碳的单一氨基酸型单体构成。相邻链的 N–H 与 C=O 之间形成大量氢键，使尼龙熔点较高（尼龙 66 约 265 °C、尼龙 6 约 220 °C）、强度高、耐磨。酰胺键吸水性较强，吸水后尺寸和性能会变化。芳香族聚酰胺（芳纶，如凯夫拉）链更刚硬，强度更高。

The numbers give monomer carbon counts: in nylon 66 the first 6 is the diamine's six carbons and the second the diacid's; nylon 6 comes from a single six-carbon amino-acid-type monomer. Dense hydrogen bonding between N–H and C=O on neighbouring chains gives high melting points (about 265 °C for nylon 66 and 220 °C for nylon 6), strength and wear resistance. Amide groups absorb water, which changes dimensions and properties. Aromatic polyamides (aramids such as Kevlar) are stiffer and even stronger.

1935 年 2 月，杜邦公司的华莱士·卡罗瑟斯团队合成了尼龙 66，1938 年公开，1939 年在纽约世博会展出，1940 年 5 月尼龙丝袜上市，首日售出约 400 万双。二战期间尼龙被大量用于降落伞、绳索和轮胎帘子线。为避开杜邦专利，德国法本公司的施拉克于 1938 年用己内酰胺开发了尼龙 6（贝纶）。卡罗瑟斯本人于 1937 年去世。

In February 1935 Wallace Carothers's team at DuPont synthesised nylon 66; it was announced in 1938, shown at the 1939 New York World's Fair, and nylon stockings went on sale in May 1940, selling about four million pairs on the first day. In the Second World War nylon went into parachutes, ropes and tyre cord. To get round DuPont's patents, Paul Schlack at IG Farben developed nylon 6 (Perlon) from caprolactam in 1938. Carothers himself died in 1937.

尼龙纤维用于丝袜、运动服、渔网、地毯和轮胎帘子线；尼龙工程塑料用于齿轮、轴承、汽车进气歧管、电动工具外壳和扎带；尼龙 12 粉末用于 3D 打印。己二酸生产过程中会排放强温室气体 N₂O，需配套分解装置。

Nylon fibre goes into hosiery, sportswear, fishing nets, carpets and tyre cord; nylon engineering plastics into gears, bearings, car intake manifolds, power-tool housings and cable ties; nylon 12 powder into 3D printing. Adipic acid production releases N₂O, a potent greenhouse gas, so plants need abatement units.