PSU and PEI for Various Medical Device Applications

Among the myriad of materials available, polysulfone (PSU) and polyetherimide (PEI) stand out for their exceptional properties and versatility. In this technical post, PDC delves into the unique properties of PSU and PEI, their versatile applications in medical devices, and the advantages they provide to both manufacturers and end-users.

Overview of PSU and PEI: Polysulfone (PSU) and polyetherimide (PEI) are high-performance engineering thermoplastics renowned for their excellent mechanical properties, thermal stability, chemical resistance, and biocompatibility. PSU exhibits exceptional heat resistance, good dimensional stability, and resistance to steam sterilization, making it ideal for applications requiring prolonged exposure to high temperatures and harsh sterilization methods. On the other hand, PEI boasts high strength and stiffness, inherent flame resistance, and resistance to hydrolysis, making it suitable for demanding applications in the medical field. 

Applications in Diverse Medical Devices: 

  1. Surgical Instruments: Both PSU and PEI are commonly used in the manufacturing of surgical instruments such as handles, forceps, and retractors due to their excellent mechanical properties, chemical resistance, and biocompatibility. These materials ensure that surgical instruments maintain their integrity and performance even under repeated sterilization cycles and harsh operating conditions. 
  2. Implantable Devices: PSU and PEI find applications in the fabrication of implantable medical devices such as orthopedic implants, cardiovascular devices, and dental implants. Their biocompatibility, dimensional stability, and resistance to body fluids make them suitable for long-term implantation, contributing to improved patient outcomes and device longevity. 
  3. Diagnostic Equipment: In diagnostic equipment such as blood analyzers, imaging devices, and diagnostic reagent containers, PSU and PEI offer excellent transparency, chemical resistance, and dimensional stability, allowing for accurate and reliable test results. Moreover, their resistance to sterilization methods ensures the integrity of diagnostic devices throughout their service life. 
  4. Fluid Handling Components: Both PSU and PEI are utilized in the fabrication of fluid handling components such as connectors, manifolds, and valves in medical devices and analytical instruments. Their resistance to chemical attack, thermal stability, and low extractable levels ensure the purity of fluids and prevent contamination, critical for maintaining the integrity of diagnostic and therapeutic procedures. 

Conclusion: In conclusion, PSU and PEI polymers play a vital role in advancing medical device manufacturing by offering exceptional mechanical properties, thermal stability, chemical resistance, and biocompatibility. Their versatility and applicability across a wide range of medical devices, coupled with their ability to withstand harsh sterilization methods and demanding operating conditions, make them indispensable materials for the healthcare industry. As we continue to push the boundaries of innovation in medical device technology, PSU and PEI will undoubtedly remain at the forefront, driving advancements in patient care, diagnostic accuracy, and therapeutic efficacy. 

Mastery in Precision Molding – Insights from Our Journey:

Having 30+ years of experience in injection molding of high heat resins, Polysulfone (PSU) and Polyetherimide (PEI) present unique challenges due to their high melting temperatures and viscosity.  As with PEEK, these resins require a thorough understanding of thermal (both heating and cooling) control to maintain flow characteristics during the fill phase and control warp post-molding.  Because of the high viscosity, it is imperative to review minimal wall thickness and overall part complexity to ensure proper fill and pack. PDC’s customization of mold flow simulations allow insight into these polymers filling complex micro geometries. Overall, PSU and PEI offer exceptional performance properties, their processing challenges, only exacerbated when components are miniaturized, require a high degree of expertise in this arena.  Having DFM, Simulation, In-House Tooling and Master Molders all under one roof have allowed PDC to lead the industry in high temperature polymer micro injection molding.