Polyphthalamides (abbreviation PPA) are less common aromatic polyamides, which are usually only in a modified form (reinforced or filled ) are used. They belong to the class of thermoplastics. A background idea behind its development was to provide a plastic that is placed between the priced engineering plastics PA, PC, PET / PBT, POM and the more expensive high-performance plastics PPS, PEI and LCP.

Suitable monomers for the production of polyphthalamides serve diamines of different chain length and the aromatic dicarboxylic acid terephthalic acid. With elimination of water, these monomers polycondense to the polymer.

Polyphthalamide with 6T - segment

Polyphthalamide with DT- segment


Polyphthalamides have a high heat resistance and good dimensional stability with little delay. The moisture absorption is only 0.1-0.3 %. Furthermore, they have a high tensile strength and stiffness. The modulus of elasticity may be up to 14 500 N · mm 2. The notched impact strength is higher than for comparable plastics.

Polyphthalamides are sold under the trade name Amodel, Grivory, Ultramid T, Akromid T, VESTAMID HTplus and Zytel HTN.


  • Walter Bright Erich Günther Harsch, Siegfried Haenle: Material Guide plastics: properties - tests - characteristics. Carl Hanser Verlag, ISBN 3-446-21437-2 (PDF)
  • Polymer group
  • Thermoplastic