Repeated autoclave. Hydrolysis resistant. Amber transparent.
Polysulfone (PSU) and polyphenylsulfone (PPSU/Radel) handle 1000+ autoclave cycles without degradation. Hot water and steam stable, transparent amber, FDA compliant. Standard for reusable medical devices, lab equipment, plumbing manifolds, aerospace interior.
At a glance
- Density
- 1.29 g/cc
- Tensile strength
- 73 MPa
- Flexural modulus
- 2.3 GPa
- Elongation
- 60%+
- HDT (1.8 MPa)
- 207 °C
- Continuous service
- 180 °C
- Transparency
- Amber
- Biocompatibility
- USP Class VI
Key data
- Density
- 1.29 g/cc
- Tensile strength
- 73 MPa
- Flexural modulus
- 2.3 GPa
- Elongation
- 60%+
- HDT (1.8 MPa)
- 207 °C
- Continuous service
- 180 °C
- Transparency
- Amber
- Biocompatibility
- USP Class VI
Sulfone polymer family.
PSU (Udel)
Udel polysulfone from Solvay. 174 °C HDT, excellent hydrolysis resistance. Standard grade, most common, cheapest of the sulfones.
PES
Polyethersulfone. 210 °C HDT — between PSU and PPSU. Slightly amber color. Used for higher-temperature service.
PPSU (Radel)
Polyphenylsulfone. 207 °C HDT + highest impact resistance of sulfones. Used for aerospace interior, medical devices requiring ultimate durability.
Medical PSU
FDA-compliant medical grade. Used for reusable medical instruments, drug-contact hardware, dialysis membranes.
FR Grade
Flame-retardant grade. Aerospace interior applications per FAR 25.853.
Glass-Filled
Glass-reinforced PSU/PPSU for structural applications requiring higher stiffness.
Three main grades: PSU (standard), PES (higher temperature), PPSU (premium — highest properties). Each serves different applications based on temperature and performance needs.
Why sulfones for medical.
1000+ autoclave cycles
PSU/PPSU survive repeated sterilization without degradation. Other plastics embrittle or discolor.
Hydrolysis resistant
Hot water, steam, disinfectants — sulfones handle it all. No chain scission like polycarbonate.
Transparent
Amber transparency enables visual inspection. PPSU slightly less clear than PSU but tougher.
FDA + USP Class VI
Medical grade compliance for reusable instruments, drug-contact hardware, dialysis equipment.
Sulfones combine hot-water stability, biocompatibility, and transparency — a unique combination for reusable medical devices.
Sulfone applications.
Reusable surgical trays
Autoclavable surgical instrument trays — survive 1000+ sterilization cycles
Dental equipment
Dental instruments, handpiece components — repeated autoclave sterilization
Laboratory ware
Lab equipment hardware, membrane housings, filtration ware
Dialysis equipment
Hemodialysis filter housings, blood-contact components
Plumbing manifolds
PPSU plumbing manifolds for hot water — resist hydrolysis at elevated temperature
Aerospace interior
FR-grade PSU/PPSU for aircraft interior components per FAR 25.853
Food service
Commercial food service equipment — repeated cleaning, dishwasher safe
Coffee equipment
Espresso machine components handling hot water and steam
Infant feeding bottles
PPSU baby bottles — stronger than polycarbonate, no bisphenol A concerns
Sulfone finishing.
As-machined
Amber transparent. PPSU slightly darker than PSU. Ra 1.6 µm typical.
Polished
Ra 0.2 µm achievable. Improves optical transmission for visual applications.
Vapor polished
Solvent vapor polishing creates optical-grade surface.
Laser marked
Good contrast on amber surface. Standard for part identification.
Bonded
Can be solvent bonded (methylene chloride) or ultrasonic welded.
Painted
Accepts paint with surface preparation.
Machined threads
Threads stable in PSU/PPSU — no cold-flow issues.
Stress-relief annealed
Post-machining annealing at 160 °C for 2 hours reduces residual stress, prevents stress cracking.
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Repeated autoclave — questions
PSU vs PPSU — key difference?
PSU (Udel): $60-90/kg, 174 °C HDT, transparent amber, slightly less tough. PPSU (Radel): $100-150/kg, 207 °C HDT, same color family, much tougher (doesn't crack under impact). PPSU is premium grade — use when impact resistance matters (baby bottles, tools subjected to drop) or higher temperature needed. PSU adequate for most autoclavable lab and medical applications.
PSU vs polycarbonate for transparent parts?
Polycarbonate: cheap ($8-12/kg), great clarity, impact resistant. Problem: hydrolyzes in hot water — not truly autoclavable (10-20 cycles max). PSU: more expensive ($60-90/kg), slight amber tint, survives 1000+ autoclave cycles. For reusable autoclavable medical applications: PSU wins. For consumer optical/impact applications: polycarbonate wins.
Stress cracking concerns?
Sulfones can stress-crack when exposed to certain solvents under stress. Common offenders: acetone, methylene chloride, some cleaners. Post-machining annealing at 160 °C for 2 hours relieves internal stress, dramatically improves chemical resistance. Design considerations: avoid sharp internal corners, avoid thin sections, test specific cleaning chemistry. Our PSU/PPSU parts are annealed as standard practice.
Machining notes?
Machines similar to polycarbonate — soft, cuts cleanly. Sharp carbide tooling, air coolant (water coolant can cause stress-cracking), climb milling, avoid flood coolant. Typical tolerance ±0.05 mm easily achieved. For optical surfaces, diamond polishing or vapor polishing after CNC. Annealing after machining is standard for stress-relief.
Temperature limit specifics?
PSU: 170 °C continuous, 180 °C peak short-term. PES: 190 °C continuous. PPSU: 180 °C continuous, 200 °C peak. All three survive standard autoclave cycles (121 °C / 15 psi / 20 minutes). For higher-temperature service (above 200 °C continuous), switch to PEI (Ultem) or PEEK.
Lead times?
PSU: 1-2 week lead time. PPSU: 2-3 weeks. Medical-grade with documentation: 3-4 weeks. Custom colors: 3-4 weeks. FR grades: 2-3 weeks. For rush, standard natural/amber PSU often available from stock.
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