Ultem: The Ultimate Engineering Material

Ultem, also known as polyetherimide (PEI), is a high-performance thermoplastic renowned for its exceptional mechanical, thermal, and chemical properties. Developed by General Electric Plastics (now SABIC), Ultem has become a critical material in various high-demand applications across multiple industries, including aerospace, automotive, electronics, and medical devices. This article explores the invention and history of Ultem, its unique properties, and its diverse applications, with a particular focus on its value in diffusion bonded manifolds for medical and life science devices.

Invention and History

Ultem polyetherimide was developed by General Electric Plastics in the late 1970s as part of a broader effort to create high-performance thermoplastics that could withstand harsh conditions while offering ease of processing. The development of Ultem was driven by the need for materials that combined the mechanical strength and thermal stability of metals with the lightweight and versatile processing characteristics of plastics.

The creation of Ultem was a significant achievement in polymer chemistry, resulting from the synthesis of a polyetherimide structure that offered a unique combination of properties. Introduced commercially in the early 1980s, Ultem quickly gained recognition for its performance in demanding applications, with the added benefit of a semi-transparent material – offering optical clarity with proper surface finishing techniques. Today, Ultem is produced and marketed by SABIC, continuing to be a preferred material in high-performance engineering applications.

Ultem PEI cnc machining

Physical Properties

Ultem is characterized by its impressive mechanical strength and toughness. It exhibits a high tensile strength, with certain grades boasting 16,000 psi, making it suitable for structural components that require durability and resistance to mechanical stress. Ultem’s high modulus of elasticity further enhances its rigidity and structural integrity, allowing it to maintain its shape and performance under load.

In addition to its strength, Ultem offers excellent impact resistance. Unlike many brittle polymers, Ultem can absorb significant energy without fracturing, making it suitable for applications where impact resistance is critical. Its low coefficient of thermal expansion ensures dimensional stability across a wide range of temperatures, reducing the risk of warping or deformation.

Thermal Properties

One of Ultem’s most notable attributes is its exceptional thermal stability. It can withstand continuous use temperatures of up to 340°F (170°C). This high heat resistance makes Ultem ideal for applications exposed to elevated temperatures, such as in aerospace and automotive industries.

Ultem also boasts a high glass transition temperature, ensuring that it remains stable and retains its mechanical properties even near its upper temperature limits. This thermal performance is crucial for components that must maintain their integrity and functionality in high-temperature and autoclave environments.

CNC machined Ultem vendor

Chemical Properties

Ultem exhibits excellent chemical resistance, making it suitable for applications involving exposure to various chemicals, including solvents, acids, and bases. Its resistance to hydrolysis ensures that it remains stable in humid or wet environments, a critical feature for applications in medical and life science devices where sterilization and cleaning are essential.

Ultem’s low moisture absorption rate further enhances its dimensional stability and maintains its mechanical properties over time, even in humid conditions. This chemical resilience, combined with its low outgassing properties, makes Ultem an ideal material for sensitive applications, such as those in the aerospace and life science industries.

Applications in Modern Industries

Aerospace Industry

In the aerospace industry, Ultem is used for a variety of components, including insulators, coolant systems, and structural parts. Its high strength-to-weight ratio and excellent thermal stability make it ideal for aerospace applications where reducing weight and maintaining performance at high temperatures are critical.

Automotive Industry

Ultem’s high thermal and mechanical performance makes it suitable for automotive applications, such as under-the-hood components, electrical connectors, and lighting systems. Its resistance to automotive fluids and ability to withstand high temperatures contribute to improved vehicle reliability and performance.

Polished Ultem machined part

Electronics and Electrical

The electronics industry benefits from Ultem’s excellent electrical insulating properties. It is used in connectors, circuit boards, and other electronic components that require high dielectric strength and thermal stability. Ultem’s low dielectric constant and dissipation factor ensure reliable performance in high-frequency applications.

Medical Devices

Ultem is widely used in medical and life science devices due to its biocompatibility, chemical resistance, and ability to withstand repeated sterilization. It is used in surgical instruments, diagnostic equipment, and a variety of laboratory devices. One of the most valuable applications of Ultem in the medical field is in diffusion bonded manifolds.

Value of Ultem in Medical and Life Science Devices

Diffusion bonded manifolds are critical components in medical and life science devices, used for fluid management and control in applications such as drug delivery systems, diagnostic instruments, and laboratory equipment. Ultem’s properties make it an ideal material for these manifolds, offering several advantages:

Bonded Ultem Manifold

Chemical Resistance and Biocompatibility

Ultem’s resistance to a wide range of chemicals ensures that it can handle various reagents and cleaning solutions without degrading or contaminating the fluid stream. Its biocompatibility makes it safe for use in medical devices that come into contact with biological tissues and fluids, ensuring patient safety and compliance with medical standards.

Thermal Stability

Diffusion bonded manifolds often operate under varying thermal conditions, from room temperature to elevated temperatures during sterilization. Ultem’s high thermal stability ensures that the manifolds maintain their integrity and performance, even after repeated sterilization cycles. This is crucial for maintaining the reliability and longevity of medical devices.

Precision and Dimensional Stability

The manufacturing of diffusion bonded manifolds requires precision to ensure accurate fluid flow and control. Ultem’s low coefficient of thermal expansion and high dimensional stability ensure that the manifolds retain their precise dimensions and performance characteristics over time, ensuring reliable operation of the medical devices.

Manifold valve assembly

Ease of Processing

Ultem can be processed using various manufacturing techniques, including precision machining, annealing, and diffusion bonding. This versatility in processing allows for the production of complex and precise manifold designs, tailored to the specific needs of medical and life science applications. The ability to create intricate and reliable manifolds enhances the functionality and efficiency of medical devices.

The Ultem-ate Conclusion

Ultem polyetherimide stands as a remarkable achievement in the field of high-performance thermoplastics. Its unique combination of mechanical strength, thermal stability, chemical resistance, and ease of processing has made it an essential material in numerous industries. From aerospace and automotive to electronics and medical devices, Ultem’s reliability and performance under extreme conditions continue to support innovation and improve the efficiency and longevity of critical components.

Bonded Ultem Chip


Its value in diffusion bonded manifolds for medical and life science devices highlights Ultem’s critical role in ensuring the reliability, safety, and efficiency of essential medical equipment. As technology and industry continue to advance, Ultem polyetherimide will undoubtedly remain a cornerstone material, enabling the development of innovative solutions and driving progress in high-performance applications.

Is your team interested in bonded Ultem manifolds or other custom Ultem parts to support your project? Reach out to the experts at Piedmont CMG for a free quote and DFM feedback on your design.