Polysulfone & PPSU supplier: hydrolysis- and heat-resistant grades
PSU and PPSU withstand hot water, steam and repeated sterilization cycles that degrade most other clear engineering plastics.
One gaylord to a truckload · A polymer chemist reviews every quote · Every prime lot from our suppliers ships with a COA
Updated October 2026
Request a Quote- Impact strength
- PSU: moderate · PPSU: excellent
- Heat (HDT)
- ~170-205°C
- Clarity
- Transparent amber
At a glance
- Form
- Pellets
- Order size
- One gaylord to a truckload
- Grades
- PSU transparent grades · PPSU (highest toughness) · Glass-filled PSU · Plumbing / NSF-relevant grades
- Paperwork
- Supplier COA on every prime lot
- Ships to
- U.S. and Canada
- Sourcing
- Matched to your spec
The short answer
PSU and PPSU are the transparent amber resins for hot water, steam and repeated sterilization. Choose PSU for hot-water and food-service parts at the lower cost. Choose PPSU when the part needs the most steam cycles, the most impact strength and better chemical resistance. The failure seen most often is stress cracking where solvents, cleaners or molded-in stress meet, and wet resin is the usual process cause.
Grades we source
Tap a grade to add it to your quote request.
About Polysulfone / PPSU
Polysulfone (PSU) and polyphenylsulfone (PPSU) hold strength and clarity through repeated steam sterilization, making them the materials of record for medical sterilization cases (non-implant), plumbing manifolds, and food-service hot-water service. PPSU holds strength through more than 1,000 steam-sterilization cycles; PSU handles repeated steam cycles too, but fewer, so PPSU is the choice for the longest-life reusable parts. PPSU also adds an impact and chemical-resistance step over PSU.
Common applications
- Sterilization trays and cases
- Hot-water plumbing manifolds and fittings
- Food-service and dairy equipment
- Aircraft interior parts
- Battery and electrical components
Typical properties
| Impact strength | PSU: moderate · PPSU: excellent |
|---|---|
| Heat (HDT) | ~170-205°C |
| Clarity | Transparent amber |
| Chemical resistance | Outstanding vs. hot water, steam, acids and bases; PSU is attacked by ketones, esters and aromatic solvents (PPSU is better); both craze in chlorinated solvents |
| Relative cost | High |
Property ranges are general guidance and vary by grade and supplier; a polymer chemist confirms the exact spec against the data sheet and certificate of analysis for your application.
Which grade to ask for
The first decision is PSU or PPSU; they are not interchangeable.
| Grade type | Use it for | Watch out for |
|---|---|---|
| PSU, unfilled transparent | Hot-water fittings, food-service and dairy parts, filter housings | Fewer steam cycles than PPSU; attacked by ketones, esters and aromatic solvents |
| PSU, glass-filled | Stiff structural and electrical parts | Opaque; shrinkage is not isotropic (about 0.29% along flow and 0.46% across at 30% glass in one producer’s data) |
| PPSU, unfilled | Sterilization trays and cases, instrument handles, PEX fittings | Costs more than PSU; its shrinkage range is wider, so do not assume a PSU tool runs PPSU to size |
| PPSU, colored healthcare grades | Color-coded instrument handles and trays | The color is part of the grade; ask for steam-cycle and biocompatibility data on that color |
| Plumbing grades (NSF/ANSI/CAN 61) | Manifolds, fittings and valve bodies in drinking water | Listings are for a formulation at a stated water temperature, and the part maker holds the listing for the finished part |
| Food-contact grades | Dairy, coffee and beverage equipment | Ask for the producer’s FDA letter for the exact grade and color |
Typical starting points. Grades vary, so confirm on the data sheet for the exact grade.
Processing notes
- Drying. Sulfones absorb moisture very quickly. PSU: 135–163°C / 275–325°F for 2–4 h. PPSU: 135–177°C / 275–350°F for 3–5 h. Target 0.02–0.05%, and feed straight from the dryer. See the drying chart for other resins.
- Melt temperature. PSU 330–390°C / 626–734°F. PPSU 350–390°C / 662–734°F. Residence of about 5–20 minutes is workable, shorter near the top of the range.
- Mold temperature. PSU 120–160°C / 248–320°F. PPSU 138–180°C / 280–356°F. The hotter end lowers molded-in stress and improves crack resistance in service.
- Shrinkage. PSU about 0.6–0.7%. PPSU about 0.6–1.0%. Glass-filled sulfones are not isotropic, despite claims you may read to the contrary.
- Regrind. Producer guidance uses about 25% same-grade regrind as a typical blend, dried like virgin. Medical tray programs may restrict it. Clear parts show yellowing and specks first.
- Most common defect. Splay and bubbles from resin that picked up moisture between dryer and press. Stress cracking in service comes next, usually from a cold mold, sharp corners or a cleaner the grade was not checked against.
What to put on the purchase order
- PSU or PPSU, by name, plus fill. Unfilled or glass-filled. A PSU quote is not a PPSU quote.
- Melt flow and test condition. Test conditions differ by producer: some test PSU and PPSU at different temperatures and loads, others use one condition for both. Copy the method and condition from your data sheet and compare like with like on the COA.
- Sterilization or water conditions. Method, temperature and expected cycle count, or water temperature and chlorine level. A polymer chemist uses this to confirm the grade.
- Color. Natural transparent amber or an opaque color. For healthcare parts, name the exact color.
- Drinking water. If the part is in potable water, the NSF/ANSI/CAN 61 listing and its temperature class (23°C / 73°F, 60°C / 140°F or 82°C / 180°F).
- Food, medical and UL documents. Ask for the producer’s FDA letter for the exact grade. UL recognition is grade-specific and color-specific; check the grade’s listing on UL Product iQ.
- COA values to check. Melt flow against the data sheet range, and glass content for filled grades.
When to consider something else
- If you need higher heat, more stiffness or aircraft-interior flame and smoke data, look at PEI.
- If you need a transparent sulfone with more heat and less creep than PSU, look at PES.
- If the part can be opaque and must resist solvents, look at PPS or PEEK.
- If the clear part never sees steam or hot water, polycarbonate costs less, but it degrades with repeated autoclaving.
- For a side-by-side of hot-water resins, see best plastic for hot water and steam.
Common questions
What is the difference between PSU and PPSU?
Both are amorphous, transparent amber sulfones. PPSU is much tougher, resists more chemicals and survives more steam cycles, and it costs more. PSU covers hot-water and food-service parts at lower cost.
How many autoclave cycles can PPSU take?
In producer tests, PPSU keeps its properties through more than 1,000 steam cycles at 132–134°C (270–273°F). Real life depends on the cleaning chemicals, steam additives and part stress. Test with your actual cycle.
Does polysulfone need to be dried?
Yes. PSU absorbs moisture very quickly. Dry it at 135–163°C (275–325°F) for 2–4 hours to 0.02–0.05%, and feed straight from the dryer to the press.
Is polysulfone food safe?
Some PSU and PPSU grades are made to comply with FDA food-contact requirements, and some are listed to NSF/ANSI/CAN 61 for drinking water. Compliance is grade-specific, so ask for the producer’s FDA letter or listing for the exact grade and color.
Tell us the Polysulfone / PPSU grade you run now
A polymer chemist reviews every request, then matches your grade or finds a qualified equivalent and prices it.
What to send for an accurate quote
- The grade name, from any supplier, or a data sheet
- Color (natural, black or a custom match)
- Fill type and percentage, if any
- Melt flow, if you know it
- Quantity for this order and what you use in a year
- Ship-to city and state or province
PSU or PPSU, matched to your steam cycles
Tell us the sulfone grade, how the part is sterilized or what water it sees, and volume; a polymer chemist reviews it and we quote.
Request a QuoteNot sure which grade to ask for?
Send the grade you run now, or describe the part. A polymer chemist reviews every request.