PSU
ASTM D6394 · ISO 1043 PSU · also Udel, Ultrason S
PSU is an amorphous bisphenol-A polysulfone (Udel P-1700, Ultrason S, D6394) with a Tg near 185 °C, supplied as transparent amber unfilled stock and in GF20, GF30, GF40, CF30, PTFE-lubricated, membrane and medical grades.
PSU grades and fills
PSU is supplied in 7 conditions, soft to hard.
Compare all 7 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
PTFE-lubricated bearing grade (typically 10–15% PTFE) | Use for sliding/wear parts needing low friction at high temperature; strength and ductility drop versus natural PSU. | 55 | 55 | 15 | 82 Shore D |
Unfilled / Natural (transparent amber, e.g. Udel P-1700) | Standard injection/extrusion grade: pick for transparency, autoclavability and general high-temperature insulating parts. | 71 | 60 | 69 HRM | |
Membrane / solution-casting grade (high, controlled molecular weight) | Choose for ultrafiltration, hemodialysis and gas-separation membranes cast from NMP/DMAc solution rather than melt processed. | 72 | 73 | 70 | 85 Shore D |
20% glass fiber reinforced | Mid-level stiffening with lower warpage than GF30; use for load-bearing housings at 120–150 °C. | 100 | 3.5 | 88 HRM | |
30% glass fiber reinforced | Highest stiffness/creep resistance and lowest CTE of the PSU family; opaque, more abrasive to tools and molds. | 117 | 2.5 | 95 HRM | |
40% Glass Fiber | Highly filled 40% short-glass polysulfone for maximum stiffness, creep resistance and low thermal expansion in electrically insulating structural parts. | 130 | 2 | 92 HRM | |
30% Carbon Fiber | Polysulfone compounded with 30% short carbon fiber for maximum stiffness, dimensional stability and static-dissipative behaviour at up to ~160 °C. | 155 | 1.7 | 95 HRM |
Supply forms, finishes and certifications
Ways PSU is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
EXT-STOCK | Extruded stock shape | Surface finish |
Medical GradeDefault | ISO 10993 / USP Class VI tested, autoclavable | Certification |
What is PSU?
PSU is an amorphous bisphenol-A polysulfone (Udel P-1700, Ultrason S, D6394) with a Tg near 185 °C, supplied as transparent amber unfilled stock and in GF20, GF30, GF40, CF30, PTFE-lubricated, membrane and medical grades. Engineers use it for repeated steam autoclaving without significant strength loss, hydrolysis resistance, dimensional stability and electrical insulation; default values are 1.24 g/cm3, 70 MPa tensile strength, 55 % elongation, 2.5 GPa modulus and 150 °C service temperature. Limits are poor UV and weathering resistance with yellowing, attack and stress cracking by aromatics, ketones, chlorinated solvents and some esters, and only moderate notched toughness. PSU has a density of 1.24 g/cm³ (0.0448 lb/in³), heavier than 63% of polymer grades. Its glass-transition temperature is 185°C (365 °F). PSU has a yield strength of 70 MPa (10.2 ksi) and a tensile strength of 71 MPa (10.3 ksi) — stronger than 79% of polymer grades. Elongation at break is 60% and the elastic modulus is 2.5 GPa (0.363 Msi).
What is PSU used for?
- Medical instrument trays and sterilization cases
- Dialyzer housings and membranes
- Food-contact containers
- Hot-water pipe fittings
- Electrical insulating components
- Reusable autoclavable medical parts
Advantages
- High strength — 70 MPa (10.2 ksi), better than 79% of polymer grades
- High service temperature — 150°C (302 °F), better than 79% of polymer grades
- Conducts heat well — 0.26 W/m·K (0.15 BTU/hr·ft·°F), better than 77% of polymer grades
- Polishes to a fine finish — 70/100, better than 77% of polymer grades
Limitations
- High embodied carbon — 7 kg CO₂/kg, worse than 77% of polymer grades
PSU properties
Typical room-temperature values in the Medical Grade condition; bars are the position among polymer grades.
Physical6
PSU has a density of 1.24 g/cm³ (0.0448 lb/in³), heavier than 63% of polymer grades. Its glass-transition temperature is 185°C (365 °F).
Mechanical15
PSU has a yield strength of 70 MPa (10.2 ksi) and a tensile strength of 71 MPa (10.3 ksi) — stronger than 79% of polymer grades. Elongation at break is 60% and the elastic modulus is 2.5 GPa (0.363 Msi).
Thermal11
PSU is rated for continuous service to 150°C (302 °F). It conducts heat at 0.26 W/m·K (0.15 BTU/hr·ft·°F), better than 77% of polymer grades. Thermal expansion is 56 µm/m·K (31.1 µin/in·°F).
Electrical7
PSU is an electrical insulator with a dielectric strength of 17 kV/mm (431.8 V/mil) and a resistivity of 1×10¹⁴ Ω·m.
Chemical & Environmental3
Corrosion resistance is very good (80/100), worse than 52% of polymer grades. UV resistance is poor.
Sustainability4
Producing a kilogram of PSU takes about 130 MJ of energy and emits 7 kg of CO₂ — more than 77% of polymer grades. Typical recycled content is 0%.
Manufacturability8
PSU's machinability is good (65/100, better than 66% of polymer grades); weldability good (60/100); formability fair (45/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the polymer family
Yield strength against density for every polymer grade FabDigit runs. PSU is highlighted; hover a dot for its name, or open the interactive family chart.
Working with PSU
Is PSU easy to machine?
Machines like a tough amorphous plastic: sharp positive-rake carbide tools, high speed, light feed, air or water-soluble coolant only (avoid ketone/chlorinated cutting fluids); anneal blanks ~165 °C to relieve stress and prevent crazing.
Can PSU be welded?
Joins well by ultrasonic, hot-plate/hot-gas and spin welding; solvent bonding with methylene chloride blends is fast but leaves stress-crack risk, so epoxy or ultrasonic is preferred for medical parts.
Can PSU be formed, bent or molded?
Dry resin 3–4 h at 135–150 °C to <0.05% moisture, mold at 330–385 °C melt with 100–160 °C tool, moderate-high injection pressure; thermoformable and extrudable, shrinkage ~0.6% natural / ~0.2% GF30.
Manufacturability
The process limits FabDigit applies to PSU. Every PSU part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Better65 / 100 |
|---|---|
| ISO material group | N.8 |
| Cutting speed (rough / finish) | 400 / 500 m/min |
| Minimum wall | 0.5 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 10× diameter |
| Best surface (machined / polished) | Ra 0.8 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Better45 / 100 |
|---|---|
| Weldability | Better60 / 100 |
Injection molding
| Mold shrinkage | — |
|---|---|
| Wall thickness | — – — |
| Recommended draft | — |
| Pre-drying | — |
PSU chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| bisphenol A (BPA) monomer unitpolycondensation with DCDPS forms the polysulfone backbone | ≈ 45 | 45 |
| 4,4'-dichlorodiphenyl sulfone (DCDPS) moaryl-ether-sulfone repeat unit -[O-C6H4-C(CH3)2-C6H4-O-C6H4-SO2-C6H4]- | ≈ 55 | 55 |
| glass fiberonly in GF variants (sized chopped E-glass) | 10 – 30 | 30 |
| PTFEonly in lubricated bearing grades | 10 – 15 | 15 |
| polysulfone polymernatural grade is 100% polymer; no filler, minimal additives | balance |
What surface finishes work on PSU?
Transparent grade can be flame- or vapor-polished and buffed to optical clarity; paints/adhesives need degreasing or plasma/corona activation; can be metallized or vacuum-sputtered, but unprotected surfaces yellow in sunlight.
Surface treatments FabDigit runs on polymer parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Injection Molding Coating
Organic Coating
Metallization / Functional
Equivalent designations
Standards and trade names that resolve to PSU in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- D6394
- ISO
- 1043 PSU
- Trade names
- UdelUltrason S
- Also called
- Polysulfone
How much does PSU cost?
PSU is a high-cost polymer ($$$$), pricier than about 59% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
PSU — frequently asked
What is PSU used for?
PSU is typically used for medical instrument trays and sterilization cases, dialyzer housings and membranes, food-contact containers, hot-water pipe fittings, electrical insulating components and reusable autoclavable medical parts. In short: high-heat steam resistant.
What is the yield strength of PSU?
PSU has a typical yield strength of 70 MPa (10.2 ksi) and a tensile strength of 71 MPa (10.3 ksi) — stronger than 79% of polymer grades. Strength varies by condition: see the 7 listed tempers.
Is PSU easy to machine?
Reasonably — machinability is rated good (65/100, better than 66% of polymer grades). Machines like a tough amorphous plastic: sharp positive-rake carbide tools, high speed, light feed, air or water-soluble coolant only (avoid ketone/chlorinated cutting fluids); anneal blanks ~165 °C to relieve stress and prevent crazing.
Can PSU be welded?
Yes — weldability is rated good (60/100). Joins well by ultrasonic, hot-plate/hot-gas and spin welding; solvent bonding with methylene chloride blends is fast but leaves stress-crack risk, so epoxy or ultrasonic is preferred for medical parts.
What surface finishes work on PSU?
Transparent grade can be flame- or vapor-polished and buffed to optical clarity; paints/adhesives need degreasing or plasma/corona activation; can be metallized or vacuum-sputtered, but unprotected surfaces yellow in sunlight.
Can PSU be formed, bent or molded?
Dry resin 3–4 h at 135–150 °C to <0.05% moisture, mold at 330–385 °C melt with 100–160 °C tool, moderate-high injection pressure; thermoformable and extrudable, shrinkage ~0.6% natural / ~0.2% GF30.
What is the maximum service temperature of PSU?
PSU is rated for continuous use to about 150°C (302 °F), and briefly to 180°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does PSU cost?
PSU is a high-cost polymer ($$$$), pricier than about 59% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Can FabDigit make parts in PSU?
Yes — PSU is available for CNC machining, sheet metal and injection molding; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- Udel PSU Design Guide & P-1700 data sheet — Solvay Specialty Polymers (2021)
- TECASON S (PSU) stock shapes datasheet — Ensinger (2022)
- CAMPUS plastics data – polysulfone (PSU) grades — CWFG / CAMPUS consortium (2023)
- Engineered Materials Handbook Vol.2: Engineering Plastics — ASM International (1988)
- ISO 527-2 / ISO 75 / ASTM D638, D790, D256, D257 test methods — ISO / ASTM (2019)
- GB/T 13527 / ISO 10993-1 biological evaluation reference for medical PSU — SAC / ISO (2018)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.