Polyetherimide (PEI, or Ultem™) is a semi-transparent, high performance polymer, combining high dielectric strength and rigidity at elevated temperatures, with long term heat resistance. When exposed to hot water and steam, PEI is resistant to hydrolysis, making it able to withstand repeated cycles in a steam autoclave. It is particularly suited for use in medical environments, food and beverage processing, pharmaceutical applications, and other situations where high purity is a must. It's hydrolytically stable, retaining 85% of its tensile strength after 10,000 hour boiling water immersion and 100% of tensile strength after 2,000 steam autoclave cycles at 270°F. It is also UV and gamma radiation resistant. FDA compliant grades are typically available.
PEI shows resistance to certain chemicals, such as hydrocarbons, alcohols and halogenated solvents. Long term creep resistance allows PEI to replace metal and other materials in many applications. Electrical properties show excellent stability under varying temperature, humidity, and frequency conditions.
+ Key Strengths:
PEI is a high strength material that is inherently flame retardant, and performs reliably in operating temperatures of 365°F (180°C). Because of this, PEI performs exceptionally well in reusable medical applications requiring repeated sterilization. It is also available in FDA compliant colors. Beyond this, PEI also has outstanding electrical properties, with one of the highest dielectric strengths of any thermoplastic material. It offers excellent dimensional stability combined with broad chemical resistance and is inherently flame resistant and low smoke generating.
- Key Drawbacks:
PEI is quite expensive compared to other thermoplastics and its chemical makeup and amber transparent color makes colorability a limitation. It requires high processing temperatures and has relatively high material and processing costs. It can be adversely affected by both strong bases and partially halogenated solvents.