Plastic Injection Molding with PEI

What is Polytherimide?

An amorphous thermoplastic material, Polyetherimide is amber and translucent in color in its unfilled organic form. Known for its high mechanical rigidity and strength, but can also be glass-filled to further enhance the tensile strength and dimensional stability. In addition to offering high dimensional stability, tensile strength, and rigidity, it has a very good resistance to hydrolysis, chemicals, and radiation. Comparable to PEEK, PEI has a lower usable temperature and impact strength. PEI also has great flammability ratings. Drawbacks for this material include: higher processing and material costs, attacked by strong bases, and limited colorability.

What is PEI Used For?

As stated above, PEI is resistant to hydrolysis, making it able to be steam sterilized many times over. Because of this it is commonly used for medical industry and scientific components. With naturally good electrical properties, PEI is commonly also used for electrical housing and insulation. At Nylacarb, we currently make electronic components using PEI because of its ability to bear high temperatures. One of these products is an internal component part of a lithium battery.

PEI is used for:

  • Medical tools
  • Automotive interior parts
  • Electrical insulation
  • Electrical housing

Polytherimide Fact Sheet

Chemical Formula:  [C37H24O6N2]

Typical Mold Temperature: 150 to 356°F

Flexural Modulus: 0.5 – 0.9 MPSI

Tensile Strength: 113-117 MPa

Heat Deflection Temperature: 390-410°F

Specific Gravity: 1.3-1.5

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