Long carbon chain nylon is nylon with an amide group in the main chain repeating unit of nylon molecule, and the length of methylene between the two amide groups is greater than 10. We call it long carbon chain nylon, including nylon 11, nylon 12, etc. PA12 is nylon 12, also known as polydodecactam, polylauractam, is a long carbon chain nylon. The basic material for its polymerization is butadiene, a semi-crystalline - crystalline thermoplastic material. Nylon 12 is the most widely used long carbon chain nylon, in addition to most of the general properties of nylon, low water absorption, and has high dimensional stability, high temperature resistance, corrosion resistance, good toughness, easy processing and other advantages. Compared with PA11, another long carbon chain nylon material, the price of butadiene, the raw material of PA12, is only one third of the price of castor oil, the raw material of PA11. It can replace PA11 and be applied in most scenes, and has a wide range of applications in automobile fuel pipe, air brake hose, submarine cable, 3D printing and many other fields. In long chain nylon, compared with other nylon materials, PA12 has great advantages, such as the lowest water absorption rate, the lowest density, low melting point, impact resistance, friction resistance, low temperature resistance, fuel resistance, good dimensional stability, good anti-noise effect. PA12 has the properties of PA6, PA66 and polyolefin (PE, PP) at the same time, achieving the combination of lightweight and physical and chemical properties, and has advantages in performance. There are a large number of non-polar methylene groups in nylon 12, which makes nylon 12 molecular chain more compliant. The amide group in nylon 12 is polar, and the cohesion energy is very large, it can form hydrogen bonds between the molecules, so that the molecular arrangement is regular. Therefore, nylon 12 has high crystallinity and high strength. Nylon 12 has low water absorption, good low temperature resistance, good air tightness, excellent alkali and oil resistance, medium resistance to alcohol, inorganic dilute acid and aromatic hydrocarbons, good mechanical and electrical properties, and is a self-flameout material. 1) Density The relative density of nylon 12 is only 1.01-1.03, which is the smallest among all engineering plastics, which has a certain effect on reducing the quality of vehicles and reducing fuel consumption. When compared by unit volume, nylon 12 has advantages in price and performance. 2) Melting point The melting point of nylon 12 is 172-178℃, slightly lower than nylon 11, can fully meet the requirements of automobile fuel pipe and brake pipe working environment temperature. 3) Water absorption As we all know, the biggest disadvantage of nylon products is large water absorption, dimensional stability is difficult to ensure. And PA12 has the lowest water absorption rate of nylon products, this is due to the methylene molecules in nylon 12 greatly reduce the hydrophilic groups, which makes nylon 12 has a great advantage. 4) Impact strength Impact strength is an important technical index, especially for nylon 12 pipe often exposed to air. Nylon 12 under -20℃ and -40℃ according to the standard test, no fracture phenomenon, fully meet the requirements of use. Nylon 12 has excellent impact resistance. 5) Low temperature performance Nylon 12 has the lowest brittleness temperature of -70 degrees Celsius, so it can be widely used in low-temperature resistant parts. 6) Flexibility The influence of plasticizer on the physical properties of nylon 12 is concentrated on the elastic modulus of resin. Nylon 12 has three basic types of resin, their main difference is due to the plasticizer content of different forms of flexibility. The elastic modulus of resin decreases with the increase of extractable component content of plasticizer. 7) Low wear and low friction performance Nylon 12 has excellent low abrasion and low friction properties and self lubricating properties, so the friction noise of nylon 12 products is very low. 8) Fuel resistance In automobiles, the mixture of oxygenated fuel, high aromatic fuel and alcohol currently used can cause the breakdown of many hose materials. After the test, only nylon 11, nylon 12 and fluorocarbon resin elastomers can be used in this environment. Almost other types of nylon melt under the action of automobile fuel, resulting in a change in size. 9) Resistance to zinc chloride solution Zinc chloride is found under the car. Under certain temperature and humidity, the salt on the road reacts with galvanized steel plate or zinc-containing primer to form the corrosive zinc chloride. In addition, ozone aging, ultraviolet radiation, temperature conditions and so on, will bring different degrees of damage to the parts, reduce the service life. Nylon 12 is very resistant to zinc chloride solution. Because there is no unsaturated double bond in nylon 12 which is susceptible to ozone attack, ozone ...