February 15, 2025 – Polyetherimide (PEI), an amorphous high-performance polymer, has been shining brightly in multiple industries due to its exceptional properties. This amber-transparent solid material inherently possesses flame retardancy and low smoke emission characteristics, boasting a UL94-V-0 flammability rating and an impressive oxygen index of 47%, which gives it a clear advantage in environments with strict fire safety requirements.
In terms of high-temperature stability, PEI’s performance is equally remarkable. With a glass transition temperature of 217°C and a heat deflection temperature reaching 220°C, it can be used stably for long periods even at 170°C. More astonishingly, under a load of 1.8MPa, its heat deflection temperature remains high at 200°C, and the onset temperature of thermal decomposition in a nitrogen environment soars to 510°C. These data fully demonstrate PEI’s outstanding performance in high-temperature conditions, making it an ideal choice for aerospace, electronics, and other high-heat-demand fields.
According to AsiaMB’s industry insights, PEI’s hydrolytic stability is also commendable. Whether resisting high temperatures or steam, PEI maintains its excellent physical and mechanical properties. Even after immersion in 120°C water for 1000 hours, its tensile strength remains stable, and repeated steam pressure treatment and vacuum drying have no impact on its performance. This exceptional stability allows PEI to be reliably used in complex environments such as high humidity and high temperatures.
In addition to the aforementioned characteristics, PEI exhibits excellent resistance to ultraviolet and γ-ray radiation. After 1000 hours of xenon lamp exposure, its tensile strength remains almost unchanged, making it particularly suitable for manufacturing products like rear reflectors for automotive headlights that are exposed to long-term outdoor lighting.
In terms of mechanical properties, PEI also shows outstanding performance. Unreinforced PEI has a tensile strength of 105MPa, a flexural modulus of 3.3GPa, and an elongation at break of up to 60%. Although its notched impact strength is relatively low, its unnotched impact strength can reach 1270J/m. By adding glass fibers, carbon fibers, or other fillers for reinforcement and modification, PEI’s performance can be further enhanced to meet the application needs of high-strength, high-rigidity engineering plastics.
Furthermore, PEI exhibits excellent electrical properties. It maintains a basically constant dielectric constant and dissipation factor over a wide range of temperatures and frequencies, with a volume resistivity above 1×10¹²Ω·cm and a dielectric strength of 33 to 35kV/mm. These excellent electrical properties make PEI suitable for use as an insulating material for electronic sensor components.
It is worth mentioning that research institutions such as Zhejiang University of Technology and Tsinghua University are also conducting in-depth studies on PEI, further enhancing its performance through the synthesis of composite materials. These research findings open up possibilities for PEI’s application in more fields and fill us with anticipation for the future of this high-performance polymer.