PEI processed parts

PEI Plastic vs. Other High-Performance Plastics: A Comprehensive Comparison by Beeplastic

Selecting the optimal plastic for an application is crucial in engineering and manufacturing. With various options on the market, it can be challenging to determine which high-performance plastic best suits your specific needs. PEI plastic is rapidly emerging as a top contender, providing exceptional properties that make it suitable across industries. This article will provide an in-depth exploration of PEI plastic, how it compares to other thermoplastics, and why it deserves consideration for your next project.

Structure of polyetherimide (PEI)


When designing parts and products, the type of plastic chosen can greatly impact functionality and lifespan. High-performance plastics have superior mechanical properties to withstand harsh conditions, but even within this category there are significant differences. PEI (polyethylenimine) plastic has been gaining popularity as engineers discover its impressive thermal, chemical, and electrical resistance.

However, how does PEI really stack up against other leading plastics like PEEK, PAI, PET, and more? This guide from Beeplastic will analyze the advantages and limitations of PEI plastic, as well as how it differs from other materials. With decades of experience providing custom plastic fabrication services, we offer an informed perspective on selecting the right plastic for your needs.

PEEK plastic

What is PEI Plastic?

PEI plastic is an amorphous thermoplastic that offers exceptional durability, stiffness, and heat resistance compared to traditional plastics. Its full name is Polyethylenimine, and it is categorized as a high-performance plastic due to its superior mechanical properties and performance capabilities.

Key benefits of PEI plastic include:

  • High heat deflection temperature
  • Resistance to hydrocarbons and solvents
  • Stability across a wide pH range
  • Excellent electrical insulating properties
  • Flame retardance and low smoke emissions
  • High impact strength and stiffness

These characteristics make PEI an extremely versatile material suitable for demanding applications in aerospace, medical devices, electrical components, automotive, and more. It maintains integrity even when exposed to continuous high temperatures, caustic chemicals, or high-energy radiation. PEI offers versatility beyond standard plastics.

Overview of High-Performance Plastics

High-performance plastics, also called engineering thermoplastics, are designed to withstand extreme conditions that would damage or degrade conventional polymers. They retain their properties through temperature fluctuations, corrosion, wear, and abrasion over long-term use.

Some of the most common high-performance plastics include:

  • PEEK (polyetheretherketone)
  • PAI (polyamide-imide)
  • PET (polyethylene terephthalate)
  • PPSU (polyphenylsulfone)
  • PSU (polysulfone)
  • PAR (polyaryletherketone)

Beeplastic specializes in machined plastic parts and shapes crafted from these advanced materials, including rods, sheets, tubes, and finished components. Our combination of CNC equipment and skilled technicians enables us to work with even the most challenging plastics.

PEI processed parts

PEI Plastic Advantages and Disadvantages

While PEI demonstrates exceptional performance across numerous metrics, it also carries some limitations depending on the application. Understanding both the pros and cons allows proper material selection.

Key advantages of PEI plastic:

  • Retains stiffness, strength, and impact resistance at high temperatures. PEI has a high heat deflection temperature around 170°C.
  • Excellent chemical resistance and electrical insulating properties. It can withstand exposure to fuels, acids, bases, and solvents that would damage other plastics.
  • Low flammability and smoke emissions. PEI meets stringent flammability standards in aviation and infrastructure.
  • Resistance to high-energy radiation. Makes it suitable for sterilization methods.
  • Lower water absorption than nylon and other engineering plastics, which reduces dimensional changes.

Potential disadvantages include:

  • Requires high mold temperatures and is difficult to thermoform compared to other plastics.
  • More prone to stress cracking than materials like PEEK.
  • Can be impacted by UV radiation and weathering over time if not protected.
  • Honeycomb structure can trap contaminants during processing.

Despite these limitations, PEI remains extremely versatile for components and parts facing thermal cycling, caustic or hazardous chemicals, radiation sterilization, or high-voltage insulation.

polyetherimide (PEI)

PEI vs. PEEK Plastic Comparison

PEEK and PEI plastics have emerged as two leading choices for replacing metals across demanding applications. How do their properties and performance stack up?

PEEK advantages:

  • Superior resistance to chemical and environmental stress cracking.
  • Higher strength and stiffness than PEI.
  • Better wear and abrasion resistance.
  • Easier to thermoform and injection mold.

PEI advantages:

  • More economical alternative to PEEK.
  • Better high temperature performance above 150°C.
  • Lower water absorption.
  • Higher radiation resistance.
  • Excellent electrical insulating properties.

While PEEK offers the highest overall mechanical performance, PEI provides comparable capabilities at a lower price point. PEI also withstands gamma or electron beam radiation better than PEEK. Consider both materials for critical components facing heat, corrosion, wear, or radiation sterilization.


Other Notable High-Performance Plastics

While PEEK and PEI are likely the top candidates for replacing metals, other thermoplastics also provide unique benefits:

PAI (polyamide-imide) offers extremely high strength and rigidity up to 290°C. It also demonstrates chemical and wear resistance, but with lower toughness than PEI. PAI withstands higher long-term heat than PEI.

PC (polycarbonate) is highly impact resistant and optically clear but has poor chemical resistance. It replaces glass in protective applications.

PET (polyethylene terephthalate) carries excellent solvent resistance but poorer mechanical performance than PEI. PET is commonly used for containers and packaging.

PPSU (polyphenylsulfone) provides high temperature resistance up to 190°C along with chemical and oxidation resistance. It is frequently used in aerospace and pharmaceutical processing.

With a wide range of polymers available, work with an experienced plastic fabricator like Beeplastic to select the best material for your application requirements and operating conditions. Minor property differences can have a big impact on real-world performance and service life.

Beeplastic Custom Plastic Services

With over 25 years in business, Beeplastic offers full-service plastic manufacturing and machining using advanced equipment and techniques. We work with clients across industries to convert stock plastic sheets, rods, and blocks into finished components and parts.

Our plastic fabrication capabilities include:

  • CNC milling, routing, and turning with tight tolerances
  • Waterjet and laser cutting of sheets/plates
  • Plastic welding services including spin welding
  • Custom plastic extrusions and molded parts
  • Plastic polishing, painting, and finishing

Whether your project calls for PEI, PEEK, acrylic, or any other plastic, Beeplastic has the expertise to machine it to spec. We handle small prototyping runs or high-volume production with fast turnarounds. Our experienced engineering team provides guidance to find the optimal materials and manufacturing methods before beginning your project.

Practical Applications and Case Studies

PEI and other high-performance plastics have proven their capabilities across demanding industries:

  • In aerospace, PEI withstands the extreme cold of cryogenic fuel systems while providing low flammability.
  • Medical device makers utilize PEI for its sterilization compatibility and biocompatibility for long-term implants.
  • PEI plastic replaces metal parts vulnerable to corrosion in offshore oil and gas operations.
  • Engineers use glass-filled PEI bearings, bushings, and wear pads for low friction and extended service life across heavy machinery.
  • PEI machine components boost uptime for semiconductor manufacturers by avoiding damage from caustic chemicals.

Beeplastic itself has produced a wide range of custom PEI plastic components for mission-critical functions. For example, we manufactured a set of PEI plastic utilities marked with measurement labels to be installed on a spacecraft exterior. The parts needed to maintain dimensional stability across a huge temperature variance while in space.

We also fabricated a series of PEI plastic timing gear covers designed to protect timing components in an aircraft engine. PEI’s strength and heat resistance were essential for preserving tight clearances and tolerances.

From this comparison, it is clear that PEI plastic holds unique advantages that make it suitable for replacing metals, glass, and other plastics across demanding applications. While no material is perfect for every operating environment, PEI’s overall balance of thermal, chemical, electrical, and mechanical properties make it one of the most versatile and high-performing options available.

It continues to see expanded use in key industries such as aerospace, automotive, semiconductor manufacturing, and medical devices. As engineers learn more about PEI’s capabilities, it is likely to displace additional plastics, ceramics, and even metals in critical components. However, every application carries unique requirements—collaborate with an experienced plastics manufacturer like Beeplastic to select the ideal material or blend for your operating conditions.

polyetherimide (PEI) plastic


Ready to leverage PEI plastic or other high-performance polymers for your next project? Beeplastic has the expertise and capabilities to take on any custom plastic machining challenge. Browse our range of plastic fabrication services or reach out for a personalized quote. Our team is ready to help engineer plastics that perform across your specific application needs.

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