PEI material - Polyetherimide

PEI polymer is an amorphous thermoplastic with high mechanical strength and rigidity. It is commonly referred to as ULTEMTM plastic or ULTEMTM material.

The PEI plastic has similar physical properties to polyarylsulfones, while offering significant advantages. In addition to its exceptional creep resistance over a wide temperature range, PEI thermoplastic can withstand high operating temperatures. PEI material is also inherently flame retardant, exibiting low smoke emission characteristics. It is therefore a preferred material for aircraft interiors.
The polyetherimide properties are rounded out by very good hydrolysis resistance and dimensional stability.

Manufacturer of PEI products and PEI parts

Ensinger offers a wide range of production processes for PEI material. In addition to PEI sheets and rods, PEI filaments and composites, Ensinger has a long track record in machining, injection molding and custom profiles. A few years ago, Ensinger introduced PEI 3D printing. This enables Ensinger to adapt production methods to the specifications of your individual application. Whether it is a unique, finely machined part or a high volume part requirement, we will find the most effective solution for your PEI application.

PEI plates and rods - manufacturer of PEI stock shapes

PEI plastic material is extruded by Ensinger in plate and rod form using Sabic's ULTEMTM resin. The unfilled ULTEMTM plastic material offered by Ensinger is translucent and amber in colour with exceptional mechanical, thermal and electrical properties. In the filled grades, the addition of glass fibre reinforcement, combined with Ensinger's proprietary extrusion processes, provides users with a polyetherimide offering that has both higher tensile strength and stiffness, as well as improved dimensional stability.

Ensinger is a global supplier of ULTEMTM plastic and offers PEI shapes such as:

  • PEI rods
  • PEI plates
  • PEI tubes (only customised)

Ensinger's PEI plastic shapes are manufactured under the brand name TECAPEI and include the following modifications:

ULTEMTM is a registered trademark of Saudi Basic Industries Corporation (Sabic).


PEI plastics offers:

  • High continuous service temperature (170 ° C) combined with high mechanical strength and stiffness, making them suitable for demanding conditions. 
  • High creep resistance over a wide temperature range
  • High dimensional stability
  • Good electrical insulation 
  • Very good hydrolysis resistance; thus suitable for repeated steam sterilisation in medical and food applications
  • Low density and high toughness; making PEI a material that can be used to reduce weight
  • Good radiation resistance
  • Low smoke emission and flame retardancy according to UL94 V-0 as key aerospace properties
  • Good chemical resistance to chlorine and caustic/acidic cleaning agents


In certain applications, PEI and PSU can be used as interchangably. They have very similar strengths and can therefore often be used for the same applications. Both PSU and PEI plastics are partially translucent, but the PEI polymer is slightly darker than PSU. PEI material does have slightly better properties compared to PSU. PEI offers a higher continuous operating temperature (170 °C compared to 160 °C), higher strength and higher stiffness. These properties give PEI a slight advantage in certain applications such as mechanically stressed components.

PEI APPLICATIONS & area of uses

Electronics industry: coils and fuses
Aerospace industry: components for antenna constructions and interior components
Chemical industry: laboratory equipment