This document provides an overview of high heat polymers for medical applications. It defines high heat polymers as polymers processed above 600°F and discusses their advantages over other polymers, including higher heat resistance and strength. The document summarizes key high heat polymers - PEEK, PPSU, PSU, PESU, PEI - outlining their properties, processing characteristics, medical uses, advantages, and limitations. It concludes that high heat polymers enable new demanding medical devices and engineers would benefit from understanding their options when selecting materials.
1. HOW TO CHOOSE THE IDEAL HIGH
HEAT POLYMER FOR YOUR
EXTRUDED MEDICAL APPLICATION
by
Jonathan Jurgaitis
Sr. Extrusion Engineer
2. Personal Introduction
• Employed at Apollo Medical Extrusion as Sr. Extrusion Engineer.
• In the extrusion industry for 23 years.
• 13 years at industrial custom profile and tubing extruder.
• 9-3/4 years in custom medical extrusion industry.
• Have been extruding high heat polymers for about 7 years, now
exclusively focusing on high heat polymer extrusion.
• Responsible for business development of high heat polymer projects,
materials research, technical assistance, tooling design, process
development and R&D processing.
3. Introduction
A profound shift is taking place in the medical industry of more minimally
invasive, quicker and more effective procedures. The goal of this shift is to
minimize patient recovery times, reduce access incision sizes and provide
better outcomes. This requires new medical devices that demand more
performance from their components. The greater demands require
components to be made of advanced materials, some of these materials
fall under the description of high heat polymers.
There are a wide range of these high heat polymers but many may be
relatively unknown to device designers and engineers. Unfamiliarity with
high heat polymers can prove challenging in choosing the ideal material
for today’s demanding and cutting edge medical devices and
components.
My aim is to share information about the variety of high heat polymers that
are available for high requirement medical applications so designers and
engineers will have the tools to better choose the ideal high heat polymer
for their devices and components.
4. Overview
• What is a high heat polymer?
• How is a high heat polymer different than other polymers?
• General medical uses and applications of high heat polymers.
• Types, properties, positives and limitations of major high heat polymer
families.
• Conclusion.
5. WHAT IS A HIGH HEAT POLYMER?
• High heat polymers fall into the description of engineering polymers but
have properties at the pinnacle of performance.
• Generally, a high heat polymer is categorized as any plastic that is
processed at temperatures at or above 600° F.
• They are sometimes also tagged
with an added descriptor to
differentiate them, such as
“Ultra” polymer.
• High heat polymers account for
a very small percentage, by
volume, of all plastics.
6. WHAT IS A HIGH HEAT POLYMER?
• Because of their high processing temps, they require specially outfitted
extruders, ideally, tooling made of special alloys and require different
downstream processing techniques.
• High heat polymers bridge the performance gap between standard
engineering materials and metals, composite materials and thermoset
plastics.
• There are semi-crystalline and amorphous high heat polymers.
• Increasingly finding applications in demanding medical devices and
procedures.
• Many high heat polymers are relatively new to the plastics industry and
just gaining interest in the medical industry.
• Customers, processors and end users could benefit from additional
information about high heat polymer properties, types and their uses.
7. HOW IS A HIGH HEAT POLYMER DIFFERENT
THAN OTHER POLYMERS?
• High heat polymers process at higher temperatures, typically 600° F +,
and therefore are more heat resistant and have higher continuous
operating temps, most well above 300° F.
• High heat polymers have stronger physical properties than other
engineering materials, such as nylon and PC, in the areas of impact
resistance, tensile and flexural strength.
• High heat polymers are very chemically resistant and can withstand all
but the harshest chemicals and environments.
• The high heat materials listed here are all flame resistant without the
need for additives.
• Some high heat polymers are moderately priced but can range up to
being rather expensive. Their different processing requirements also
tend make them more expensive to process.
• All high heat polymers are considered rigid materials and do not come
in varying durometers.
8. GENERAL MEDICAL USES AND APPLICATIONS
OF HIGH HEAT POLYMERS
• All the high heat materials that will be covered here have ISO 10993
and/or USP Class VI approval, they are suitable for medical applications
and up to permanent implantation with some grades.
• Because of the strength and stiffness of these materials they tend to be
used as structural aspects of a device.
• These materials have excellent pushability and torque properties even at
very small diameters so they may be able to eliminate braid and coil
reinforcement in some instances.
• Orthopedic and dental applications are common because of their
similarity to the density and strength of bone.
• High heat polymers can replace stainless steel because their strength is
approaching that of stainless steel, but can add flexibility, transparency
and easier attachment methods to a device.
• High heat polymers are suitable for one time use applications but also for
durable devices because of their strength and sterilization performance.
9. TYPES, PROPERTIES, POSITIVES & LIMITATIONS OF
MAJOR HIGH HEAT POLYMERS
We will be covering the more common types of high heat polymers, PEEK,
PPSU, PSU, PESU* and PEI**, their main properties, costs and their positive
and limiting factors.
Each of these materials have different grades designed for different
processing methods and end uses but all have grades suitable for
extrusion.
*PEEK, PPSU, PSU and PESU information will be based on Solvay Specialty
Polymers’ versions of these materials.
**PEI information will be based on Ultem, manufactured by SABIC.
10. PEEK (POLYETHERETHERKETONE)
• PEEK is currently the high heat polymer “buzz” material in medical
applications.
• PEEK is a semi-crystalline polymer. This means that a portion of the
molecules align during proper processing and form crystals. This
crystallinity is partly what gives PEEK superior properties.
• Extreme continuous use temperature of 465° F +.
• Excellent chemical resistance to all hospital disinfectants.
• Highest stiffness of these materials.
• Highest tensile and flexural strength and lowest elongation of these
materials.
• High purity, very bio-stable.
• Smooth, glossy, low energy surface finish.
• Permanent implant grade available. Must go through extensive
approval process per application.
11. MEDICAL DEVICE APPLICATIONS, EXTRUSION
• PEEK is finding an increase in new device applications. Currently, PEEK is
being used in many orthopedic applications for long-term implants
primarily for spine and bone-screw applications. While most of these
applications are molded components bone-screws can be machined
from PEEK extrusions.
• Developing markets for PEEK extrusions include
• Cardiovascular applications
• Neurovascular applications
• Atrial Fibrillation (due to PEEK’s insulating properties & heat resistance)
• Artherectomey devices (due to PEEK’s insulating properties & heat resistance)
12. PEEK POSITIVES & LIMITATIONS
• Positives
• Can be extruded into large diameter and micro tubing, thin walls, multi-
lumens, rods, mandrels and filament.
• Can be compounded to custom colors, with additives and reinforcements.
• Easier to cut, can be heat formed & RF welded.
• Can withstand 40 kGy of Gamma, greater than 1000 steam sterilization
cycles, and 100 or more cycles of all other sterilization methods.
• Limitations
• High raw material costs. Compounded costs can be well over $100/lb.
• Opaque beige color that may not be aesthetically pleasing, can cause
limitations for some colors. Some colors and additive types can be limited
because of high process temps.
• Not as “tough” as other high heat polymers.
• Needs special surface preparation prior to printing.
• Special tooling required for some configurations.
13. PEEK ALTERNATIVE PAEK (POLYARYLETHERKETONE)
• PAEK has very similar properties to PEEK with only slightly better or worse
performance in various areas. (See comparison chart below)
• Still semi-crystalline.
• Approximately 20% to 30% lower raw material costs.
• Many of the same positives & limitations as PEEK.
14. AMORPHOUS HIGH HEAT POLYMERS
The remainder of the high heat polymers to be discussed are all
amorphous and transparent. Amorphous materials do not have a distinct
melting temperature and no crystalline structure. (See comparison chart
below)
15. PPSU (POLYPHENYLSULFONE)
• PPSU is the highest performing sulfone polymer.
• PPSU has the highest heat resistance of all the sulfones.
• Continuous use temperature of about 400° F.
• Excellent chemical resistance to all hospital disinfectants.
• Hydrolytically stable for high heat and humidity environments.
• Excellent ductility and toughness.
• Potential applications: steerable catheters, fluid transfer of aggressive
chemicals and drugs.
• Permanent implant grade available. Must go through extensive
approval process per application.
• Permanent applications such as wire lead coatings and orthopedics.
16. PPSU POSITIVES & LIMITATIONS
• Positives
• Can be extruded into large and micro tubing, thin walls, multi-lumen, rods,
and filament.
• Can be compounded to custom colors, with additives and reinforcements.
• Transparent. Can be made with transparent color tints.
• Can be heat formed, RF welded and reflowed.
• Can be printed on without significant surface preparation.
• Can withstand 40 kGy of Gamma, greater than 1000 steam sterilization
cycles, and 100 or more cycles of all other sterilization methods.
• Limitations
• Highest raw material cost of all the sulfones and Ultem, but less than PEEK.
• Transparent amber color that may affect some colors. Some colors and
additive types can be limited because of high process temps.
• Lower tensile and flexural strengths than other sulfones and Ultem.
• Special tooling required for some configurations.
17. PSU (POLYSULFONE)
• PSU is a high strength sulfone polymer.
• Continuous use temperature of about 345° F.
• Good chemical resistance to many hospital disinfectants.
• Hydrolytically stable for high heat and humidity environments.
• Better ductility and toughness.
• High clarity.
• Potential applications: dental tools and components.
• Higher performance alternative to polycarbonate. Does not require
tinting to compensate for Gamma sterilization effects like
polycarbonate.
• Permanent implant grade available. Must go through extensive
approval process per application.
18. PSU POSITIVES & LIMITATIONS
• Positives
• Can be extruded into large and micro tubing, thin walls, multi-lumen, rods,
and filament.
• Can be compounded to custom colors, with additives and reinforcements.
• High clarity. Can be made with transparent color tints.
• Can be heat formed, RF welded and reflowed.
• Can be printed on without significant surface preparation.
• Can withstand 40 kGy of Gamma and up to 100 cycles of all other
sterilization methods.
• Moderate raw material costs similar to PESU and Ultem.
• Limitations
• Decreased sterilization resistance compared to PPSU
• Can limit some colors and additive types because of high process temps.
• Lower tensile and flexural strengths than PESU and Ultem.
• Special tooling required for some configurations.
19. PESU (POLYETHER SULFONE)
• PESU is a very high strength sulfone polymer.
• Continuous use temperature of about 390° F.
• Better chemical resistance to many hospital disinfectants.
• Hydrolytically stable for high heat and humidity environments.
• Highest stiffness of the sulfones, can eliminate braiding and
reinforcement in some applications.
• High hardness.
• High clarity.
• Good alternative to Ultem with higher clarity.
• Highest performance alternative to polycarbonate. Does not require
tinting to compensate for Gamma sterilization effects like
polycarbonate.
• Potential applications: sight windows and clear patient access devices.
20. PESU POSITIVES & LIMITATIONS
• Positives
• Can be extruded into large and micro tubing, thin walls, multi-lumen, rods,
and filament.
• Can be compounded to custom colors, with additives and reinforcements.
• High clarity. Can be made with transparent color tints.
• Can be heat formed, RF welded and reflowed.
• Can be printed on without significant surface preparation.
• Can withstand 4 megarads of Gamma, greater than 1000 steam sterilization
cycles and 100 or more cycles of all other sterilization methods.
• Moderate raw material costs similar to PSU and Ultem.
• Limitations
• Can limit some colors and additive types because of high process temps.
• Slightly lower tensile and flexural strengths than Ultem.
• Special tooling required for some configurations.
21. PEI (POLYETHERIMIDE)
• PEI is a very high strength amorphous polymer.
• A thermoplastic variation of PI.
• Continuous use temperature of about 400° F.
• Better chemical resistance to many hospital disinfectants.
• Hydrolytically stable for high heat and humidity environments.
• Higher stiffness, strength and tensile properties than the sulfones.
• Excellent color stability through many sterilization cycles.
• Potential applications: device sheaths, access devices, sterilization tray
dividers and supports, dental tool parts and fixtures.
• Ultem is a well known brand name among high heat polymers.
22. PEI POSITIVES & LIMITATIONS
• Positives
• Can be extruded into large and micro tubing, thin walls, multi-lumen, rods,
and filament.
• Can be compounded to custom colors, with additives and reinforcements.
• Transparent. Can be made with transparent color tints.
• Can be heat formed, RF welded and reflowed.
• Can be printed on without significant surface preparation.
• Can withstand greater than 1000 steam sterilization cycles, and is suitable
for Gamma, EtO and vaporized hydrogen peroxide sterilization processes.
• Moderate raw material costs, similar to PSU and PESU.
• Limitations
• Transparent amber color that can affect some colors. Can limit some colors
and additive types because of high process temps.
• Potentially long lead times for raw material.
• Special tooling required for some configurations.
23. OTHER HIGH HEAT POLYMERS
There are a variety of other high heat polymer families that fall into similar
performance property ranges as those discussed here.
Many other high heat polymer types have extrusion grades but may have
notable restrictions that could limit the types of extrudable parts.
Other high heat polymer types beyond those listed here, tend to be
formulated for more targeted applications and/or specific physical,
chemical or thermal properties.
The high heat materials previously discussed here are more common, have
good medical application support and mostly have a reliable supply
channel. That is not to say that materials not covered in this presentation
should be avoided.
24. CONCLUSION
Extrusion of medical components out of high heat polymers is a relatively
new type of application area in the medical industry. High heat materials
have added a level of performance that was relatively unknown until
somewhat recently.
Navigating the properties and differences between high heat polymers
requires those in development and specification roles to gain a new
knowledge set. The goal of this presentation was to provide a high-level
overview of these materials to quickly help designers and engineers gain
awareness of the many high heat material options that are available.
Knowledge of and familiarity with these high heat materials will enable
designers and engineers to specify the ideal high heat polymer for their
application and open up a brave new world of medical devices.
Thank you for your time and attention.
25. CREDITS
• All material properties and descriptions for Solvay Specialty Polymers
brand materials were compiled from technical data sheets, processing
guides and other material literature generated by Solvay Specialty
Polymers.
• All material comparison charts used herein were copied from
corresponding Solvay Specialty Polymers webpages.
• All comparison information between Solvay Specialty Polymers brand
materials and Ultem were taken from literature generated by Solvay
Specialty Polymers.
• All Ultem material properties and descriptions were taken from technical
data sheets and material literature generated by SABIC. Ultem is
manufactured by SABIC.
• All PEEK extrusion medical application information provided by Joe
Stephens, Apollo Medical Extrusion VP of Sales and Marketing.