Polyamideimide - PAI

Polyamideimide (PAI) materials are amorphous, high performance, strongly colored polymers with linear predominantly aromatic molecules of high thermal stability. They are usually melt-processed, but are infusible in their fully finished form after post-curing.

If semi-fabricated items are machined, additional post-curing is recommended to achieve maximum properties.

PAI have good wear and radiation resistance, very good high temperature properties (approaching those of polyimides), inherently low flammability and smoke emission.

They have the highest strength of any unreinforced thermoplastic, but are extremely expensive and attacked by alkalis.

Polymer Type



Properties approaching those of Polyimide, yet melt processable.  Highest strength of any unreinforced thermoplastic. Good wear resistance. Low smoke emission. Good radiation resistance.


Polyamideimide is expensive and can be attacked by alkalies.


Applications of PAI include valves, bearings, electrical connectors, gears and general mechanical components.

Parts for jet engines, internal combustion engines, printed circuit boards and thrust washers.

Internal combustion engines often use Polyamideimide (PAI) materials. Image Credit: ShutterStock/Sergey Kohl

Internal combustion engines often use Polyamideimide (PAI) materials. Image Credit: ShutterStock/Sergey Kohl

Typical Properties

Property Value
Density (g/cm3) 1.40
Surface Hardness RM109
Tensile Strength (MPa) 185
Flexural Modulus (GPa) 4.58
Notched Izod (kJ/m) 0.13
Linear Expansion (/°C x 10-5) 3.6
Elongation at Break (%) 12
Strain at Yield (%) 8
Max. Operating Temp. (°C) 210
Water Absorption (%) 0.28
Oxygen Index (%) 43
Flammability UL94 V0
Volume Resistivity (log ohm.cm) 17
Dielectric Strength (MV/m) 23
Dissipation Factor 1 kHz 0.001
Dielectric Constant 1 kHz 3.5
HDT @ 0.45 MPa (°C) 260+
HDT @ 1.80 MPa (°C) 274
Material. Drying hrs @ (°C) 16 @ 150
Melting Temp. Range (°C) 315 - 360
Mould Shrinkage (%) 0.7
Mould Temp. Range (°C) 180 - 260

Source : Abstracted from Plascams

For more information on Plascams please visit RAPRA Technology Ltd.

Tell Us What You Think

Do you have a review, update or anything you would like to add to this article?

Leave your feedback