Polyphthalamide

Repeating unit of polyphthalamide

Polyphthalamide (aka. PPA,[1] High Performance Polyamide) is a subset of thermoplastic synthetic resins in the polyamide (nylon) family defined as when 55% or more moles of the carboxylic acid portion of the repeating unit in the polymer chain is composed of a combination of terephthalic (TPA) and isophthalic (IPA) acids.[2] The substitution of aliphatic diacids by aromatic diacids in the polymer backbone increases the melting point, glass transition temperature, chemical resistance and stiffness.[3][4]

PPA based resins are molded into parts to replace metals in applications requiring high temperature resistance such as automotive powertrain components, the housing for high temperature electrical connectors and many other uses.

Formulated PPA granules ready for molding
  1. ^ Care should be taken not to confuse this with 'PP&A', which stands for polyester, polyamide and acrylate polymers - all of which are used to make fibres. See doi:10.1016/j.jhazmat.2019.02.067.
  2. ^ ASTM standard D 5336 -15a
  3. ^ Cousin, Thibault; Galy, Jocelyne; Dupuy, Jérôme (2012). "Molecular modelling of polyphthalamides thermal properties: Comparison between modelling and experimental results". Polymer. 53 (15): 3203–10. doi:10.1016/j.polymer.2012.05.051.
  4. ^ Harper, Charles A. (2002). Handbook of plastics, elastomers, and composites. McGraw-Hill. pp. 51–52. ISBN 978-0-07-138476-6.