Polyamides PA

In terms of annual production volume, number of different polymers and variety of applications, the polyamide family is the largest of the five major technical polymer families (the other four being polycarbonates, polyacetals, thermoplastic polyesters and polyoxyphenylenes). Historically the oldest, it has benefited from the size effect on monomer costs due to the high tonnages of polyamides 6 and 6-6 produced for the textile industry.

Polyamides, prepared by polycondensation of difunctional monomers, are linear macromolecular compounds comprising recurring amide units (—CO—NH— ).

• Standard designation (NF ISO 1874-1 of October 1988)

  Aliphatic polyamides are identified by numbers indicating the respective number of carbon atoms present in their monomers. Two numbers separated by a dash are used when polymers result from the condensation of a diamine with a diacid, the first number characterizing the number of carbon atoms separating the diamine nitrogen atoms, the second corresponding to the total number of carbon atoms present in the diacid.

  When monomers are amino acids or lactams, the single number used is the total number of carbon atoms present in the monomer molecule.

  Monomers comprising aromatic and/or cycloaliphatic rings are usually coded with a single letter or a short combination of letters corresponding to the chemical name of the ring structure.

  In the nomenclature used for copolymers, the figures for the various comonomers are separated by slashes, with the main component listed first, followed by the minor components in descending order of content.

  The main manufacturers and their brand names are listed in .