What Is Polyetherimide (PEI)?
Polyetherimide (often abbreviated as “PEI”) is a high-performance thermoplastic polymer known for its excellent balance of mechanical, thermal, and chemical properties.
Here are some key characteristics of PEI:
- Chemical Structure: PEI is an amorphous polymer derived from the polymerization of an aromatic dianhydride and an aromatic diamine.
- High-Temperature Resistance: PEI can operate continuously at temperatures up to 170°C (340°F) and can withstand short-term exposure of higher temperatures.
- Mechanical Strength: PEI exhibits high tensile strength and rigidity, even at elevated temperatures. It also has good impact resistance.
- Flame Resistance: PEI is inherently flame retardant and often meets the requirements of UL94 V-0 without the need for additives.
- Chemical Resistance: PEI resists a wide range of chemicals, including automotive fluids, fully halogenated hydrocarbons, alcohols, and aqueous solutions.
- Electrical Properties: PEI has stable electrical properties over a wide frequency and temperature range, making it suitable for electrical and electronic applications.
- Transparency: PEI is naturally amber in color and is transparent to infrared radiation, making it useful in heat-resistant optical applications.
- Applications: Due to its unique combination of properties, PEI is used in a variety of industries, including aerospace, automotive, electronics, medical, and more. Common applications include electrical connectors, microwave components, automotive lamp housings, and medical devices.
- Trade Names: PEI is commercially available under various trade names, with “Ultem” by SABIC being one of the most well-known.
- Processing: PEI can be processed using conventional injection molding, extrusion, and blow-molding techniques.
In summary, polyetherimide is a versatile high-performance polymer that offers a combination of high temperature, mechanical strength, and chemical resistance, making it suitable for demanding applications in various industries.