When it comes to patient safety and device reliability, few people ever talk about the materials used to manufacture widely used non-invasive medical devices. But, they should. From diagnostic housings to reusable handles and even connectors, every component in a medical device needs to balance mechanical performance, biocompatibility and regulatory compliance. And all while meeting the design and sterilization demands prioritized in clinical environments.
While there are a number of engineering resins available, polyetherimide (PEI) and polyphenylene oxide (PPO) stand out for their exceptional strength, heat resistance, and stability. So we’re going to focus on those today.
As the medical industry continues to evolve towards safer, smarter, and more sustainable materials, choosing the right engineering resin becomes a critical decision. Understanding the distinct benefits of PEI and PPO and how they compare to other commonly used polymers goes a long ways in helping medical device engineers better design for safety and longevity, as well as compliance.
Let’s dig in.
Why PEI and PPO Are Ideal for Non-Invasive Medical Devices
Non-invasive medical devices have to do more than just function (though that’s important), they have to perform reliably, often under tough conditions. From frequent sterilization to exposure to harsh disinfectants, these products need materials that won’t crack, warp, or degrade over time. That’s where polyetherimide (PEI) and polyphenylene oxide (PPO) come in. Both offer a level of performance that goes beyond what’s possible with general-purpose plastics.
PEI is known for its ability to withstand high heat, maintaining its structure even during repeated autoclave sterilization. In case you’re curious, “autoclave sterilization” is a high temp, high pressure steam process used to kill bacteria, viruses, fungi, and spores. If materials are weak or questionable, such high heat can degrade the materials pretty fast.
PEi delivers the kind of dimensional stability and stiffness engineers count on when designing reusable components. Again, think heat.
PPO, on the other hand, brings excellent hydrolytic stability and chemical resistance. That makes it a strong choice for products exposed to moisture, cleaning solutions, and temperature changes.
Both PEI and PPO also maintain their form in humid environments (think steam again) and can be formulated to meet key medical standards like ISO 10993 or USP Class VI for biocompatibility. That means they’re safe for skin contact and patient handling which is essential for non-invasive devices used every day in clinical settings.
When compared to more common materials like polycarbonate (PC), acrylonitrile butadiene styrene (ABS), or polyvinyl chloride (PVC), PEI and PPO stand out. While those resins work well for lightweight housings or disposables, they tend to lose shape under high heat or after multiple sterilization cycles. PEI and PPO hold up longer, keeping their integrity and performance through repeated use.
For manufacturers looking for a balance of safety, durability, and design flexibility, these resins deliver by helping bridge the gap between standard thermoplastics and the high-performance demands of modern medical devices.
Key Applications in Non-Invasive Medical Devices
PEI and PPO resins aren’t just strong on paper, they prove their value in real-world medical settings every day.
Their ability to resist heat, chemicals, and wear makes them reliable choices for components that must perform consistently, even after repeated cleaning or sterilization.
Here are some of the most common areas where these materials stand out.
Diagnostic Equipment and Device Housings
From blood analyzers and patient monitoring systems to imaging units and centrifuge housings, non-invasive diagnostic equipment depends on materials that can handle constant use without losing dimensional accuracy. PEI and PPO provide the rigidity and thermal stability needed to protect sensitive electronics while keeping weight and manufacturing costs under control. Their smooth surface finishes also make them easier to clean, a key advantage in clinical environments where hygiene is non-negotiable.
Reusable Handles, Trays, and Connectors
For reusable surgical tools, autoclave trays, and instrument handles that undergo repeated sterilization, PEI is often the go-to choice.
It keeps its form and mechanical properties even after dozens of sterilization cycles. PPO also performs well in connectors, tube fittings, and ergonomic grips where moisture and repeated handling come into play.
Both materials can be custom-formulated to improve grip, color stability, or resistance to stress cracking.
Fluid Management and Delivery Systems
When it comes to non-implantable devices that move or manage fluids, like pumps, valves, or external delivery cartridges, PEI and PPO deliver consistent performance.
Their low moisture absorption helps maintain precision fit and function, while their chemical resistance protects against degradation from cleaning solutions or reagents.
These examples show why PEI and PPO resins have become dependable materials for engineers designing next-generation medical devices that prioritize safety, reliability, and longevity.
Design and Processing Considerations
Selecting the right resin is only part of the equation.
How it’s processed and designed into a device can make or break overall performance.
PEI and PPO both offer excellent processability for complex geometries, but there are a few considerations that medical device engineers should keep in mind to get the most out of these materials.
Moldability and Dimensional Precision
Can it shape? And stay that way?
PEI and PPO resins allow for tight tolerances and precise molding, which is critical when parts need to align perfectly in diagnostic systems or reusable tools. Their inherent stiffness helps prevent warping during cooling, while their low moisture absorption keeps dimensions stable after production. These traits make both materials ideal for components that require repeatable accuracy, such as instrument housings, pump components, and sensor enclosures.
Color Matching and Transparency Options
While performance often takes center stage, aesthetics matter too; especially in medical environments where color coding, clarity, and clean appearance all contribute to usability and brand consistency.
PEI offers natural transparency with a slight amber hue, while PPO can be easily pigmented for opaque or translucent applications.
Polymer Resources can custom-compound both materials to achieve the exact color, opacity, or finish required, without compromising performance or regulatory compliance.
Maintaining Compliance Through Processing
It’s important to note that not all grades of PEI or PPO are created equal.
Medical-grade formulations from suppliers like Polymer Resources are designed to meet FDA and ISO requirements, including biocompatibility and lot-to-lot consistency. Proper drying, controlled processing temperatures, and post-mold conditioning help ensure these resins retain their mechanical properties and compliance through every production cycle.
From design to manufacturing, the key takeaway is simple: when processed correctly, PEI and PPO resins deliver the dimensional accuracy, sterilization resistance, and clean aesthetics that non-invasive medical devices demand.
Sustainability and Supply Chain Reliability
Because both materials are reusable and recyclable, they help extend the lifespan of medical components and reduce the need for frequent replacements. Their ability to endure multiple sterilization cycles also supports sustainability by cutting down on disposable plastics. For OEMs pursuing eco-conscious product lines, this can translate into lower overall material consumption without compromising safety or compliance.
On the production side, Polymer Resources manufactures and compounds materials domestically, which helps reduce lead times and minimize the supply chain risks associated with overseas sourcing (particularly related to tariffs).
Consistent, U.S.-based production also ensures that each formulation maintains the same high quality and regulatory traceability, critical for customers operating in the medical sector.
With PEI and PPO, manufacturers can count on a reliable supply of medical-grade resin solutions that perform, comply, and align with long-term sustainability goals.
Partnering with Polymer Resources
Selecting the right resin for a non-invasive medical device is about more than performance; it’s about trust.
Polymer Resources partners with medical manufacturers to deliver custom PEI and PPO formulations that meet strict standards for sterilization, strength, and biocompatibility.
Our U.S.-based team provides consistent, medical-grade compounding with precise color matching, transparency options, and regulatory documentation. From material selection to processing support, we help engineers design safer, smarter, and more sustainable devices with confidence.