Polyamide, commonly known as Nylon, is a generic term for thermoplastic resins containing repeating amide groups - [NHCO]- in the main chain of the molecule, including aliphatic PA, aliphatic-aromatic PA and aromatic PA. The name of these resins is determined by the specific number of carbon atoms in the synthesis monomer. It was invented by the famous American chemist Carothers and his scientific team.
Molecular structure.The commonly used nylon fibres can be divided into two main groups.
One type is poly diamines with diacid, obtained by the condensation of diamines and diacids, whose long-chain molecules have the chemical structure formula H-[HN(CH2)xNHCO(CH2)yCO]-OH.
The relative molecular weight of this type of nylon is generally 17,000-23,000. different nylon products can be obtained depending on the number of carbon atoms of the diamine and diacid used and can be distinguished by the number added to the nylon, where the former number is the number of carbon atoms of the diamine and the latter number is the number of carbon atoms of the diacid. For example, nylon 66, which means it is made from the condensation of hexamethylene diamine and adipic acid; nylon 610, which means it is made from hexamethylene diamine and sebacic acid.
