Desktop
Resin Data
PES

Polietersulfona (PESU)

PES·High Performance·Amorphous

PES (Polyethersulfone, also PESU) is the world's #1 polymer for hemodialysis membranes —the plastic filter keeping millions of people with kidney failure alive— thanks to a unique combination: amorphous transparent pale amber, Tg of 225°C, HDT of 205°C, exceptional hydrolysis resistance, and proven biocompatibility in chronic blood contact. It's the "middle brother" of the polysulfone family, between PSU (cheaper, lower temp) and PPSU (higher impact, biphenyl backbone).

Global brands: BASF Ultrason E (grades E2010, E6020 are world references), Solvay/Syensqo Veradel PESU, Sumitomo Sumika Excel. Its backbone alternates ether groups (-O-) and sulfone groups (-SO₂-) between phenyl rings, giving it exceptional thermal stability without needing to crystallize —it's 100% amorphous and processes with fewer issues than a semi-crystalline like PEEK.

Processing-wise: drying 150°C × 4 h (hygroscopic — key), melt 340-380°C, mold 140-180°C mandatory (better 160°C+), low isotropic shrinkage 0.5-0.7%. Dominant applications: hemodialysis and ultrafiltration membranes (medical filters, water), BPA-free baby bottles, autoclavable medical instruments, ovenable parts (microwave), aerospace connectors. Cost $15-30/kg —more accessible than PEI and much more than PEEK. Are you running PES? Share your experience with membranes or autoclave in the comments.

The ranges shown in these data tables were compiled by the MVPS team from various parameter sheets and literature, integrating the lower and upper limits for each material type.

This information must be carefully reviewed when developing injection molding processes. Final ranges and processing tolerances are the responsibility of the engineer in charge.

These ranges are not recommended for developing specific process tolerances. MVPS always recommends requesting and consulting the supplier's data sheet.

General Properties

Chemical StructureAmorphous
Specific Gravity (Density)1.37:1
L/D Ratio18 – 24
Compression Ratio2 – 2.5
Tonnage Factor4.63 – 6.18kN/cm²
Thermal Diffusivity0.1194mm²/s
Max Shear Rate50,0001/s
Shrinkage0.5 – 0.7%
Regrind❌ Not allowed
Heat Deflection (HDT) @ 1.82 MPa196°C
Glass Transition (Tg) @ 10°C/min210°C
Vicat Softening @ 50N210°C

Drying

Drying Temperature129 – 138°C
Drying Time2 – 6h
Recommended Moisture0.05%
Recommended Dryer TypeDesiccant
Dew Point-40°C

Temperatures

Melt288 – 410°C
Nozzle341 – 391°C
Front341 – 391°C
Middle321 – 371°C
Rear299 – 349°C
Demolding96 – 210°C
Mold (Cooling)79 – 199°C
Feed Throat35 – 79°C

Processing

Back Pressure1.7 – 5.2bar
Screw Speed30 – 100RPM
Injection SpeedMedium
Barrel Occupancy25 – 75%
Injection Pressure700 – 1,500Pbar
Holding Pressure175 – 1,200Pbar
Cushion6.4 – 12.7mm

Mold

Runner Diameter3.05 – 6.1mm
Gate Diameter0.76 – 1.52mm
Gate Area0.46 – 1.82mm²
Wall Thickness0.51 – 4.57mm

Venting

Depth (Vent Depth)0.0203 – 0.0508mm
Land (Vent Land)0.762 – 1.52mm
Width (Vent / Clearance)3.05 – 10.2mm
Relief (Relief Channel)0.2032 – 0.4064mm

Frequently asked questions

**PES** (Polyethersulfone, also written **PESU**) is an aromatic amorphous thermoplastic with a structure alternating **sulfone groups** (-SO₂-) and **ether groups** (-O-) between phenyl rings. The sulfone group —with two oxygen atoms double-bonded to sulfur— gives it thermal rigidity. The "polysulfone" family has 3 members: - **PSU** (Polysulfone): contains isopropylidene (-C(CH₃)₂-) in the backbone. Tg ~190°C. Cheapest and easiest to process. - **PES**: only sulfone and ether groups. Tg ~225°C. Temperature/cost balance. - **PPSU** ([Polyphenylsulfone](/en/desktop/datos-de-resina/ppsu)): contains **biphenyl** (-C₆H₄-C₆H₄-) instead of isopropylidene. Tg ~220°C but much higher impact strength and hydrolysis resistance.
Five combined reasons no other polymer matches: - **(1) Biocompatibility in chronic blood contact**: low coagulation, low plasma protein adsorption, no significant inflammatory response. - **(2) Ability to form membranes with controlled pores** 1-100 nm —ideal range to retain large proteins and pass urea, creatinine, and small toxins. - **(3) High permeability** to low-molecular-weight molecules —efficient filtration. - **(4) Endotoxin retention** —prevents bacteria and toxins from passing to the patient. - **(5) Sterilizable** by gamma, EtO, and steam without membrane degradation. Leading brands in hemodialysis filters: **Fresenius FX** (Helixone Plus, modified PES), **B. Braun Diacap Pro**, **Toray Filtryzer BG** —all based on PES.
- **Drying**: 150°C × 4 h in desiccant dryer with dew point <-30°C. Final moisture <0.05% (target <0.02% for optical parts). - **Melt**: 340-380°C (standard BASF Ultrason E: 360°C). GF grades can go up to 390°C. - **Mold**: **140-180°C mandatory** —ideally 160°C+ for transparent parts. Cold mold generates stress causing spontaneous cracks months later. - **Residence**: <10 min. PES is thermally stable but sustained temperature >390°C degrades it. - **Injection speed**: medium. Shear thinning aids thin-wall filling.
**Yes, and it replaced polycarbonate in many premium markets**. Advantages: - **BPA-free**: doesn't contain bisphenol-A, monomer present in PC suspected as endocrine disruptor (banned in EU baby bottles since 2011, USA 2012). - **Sterilizable by boiling and steam**: 100°C+ infinite times without yellowing (vs PC which yellows and degrades). - **FDA approved** for food contact. - **Natural pale amber color** (not crystal clear —some brands present it as "natural amber"). Brands: **NUK Smart Soothe**, **Tommee Tippee Heat Resistant**, **Difrax** use PES. **Limitation**: more expensive than PC ($15-30/kg vs $3-5/kg) and color not perfectly transparent.
**0.5-0.7% isotropic** —low, predictable, similar to PEI and PSU. Being amorphous, no crystalline directionality. With 30% GF: drops to 0.2-0.4% with mild fiber-orientation anisotropy. Predictability is key for **medical parts with strict tolerances** (luers, syringes, connectors) and **dental parts** that assemble with metal or ceramic.
Both are amorphous aromatic transparent amber, very similar. Key differences: - **PES wins on**: **hydrolysis resistance** (repeated boiling-water autoclave is its strength), **biocompatibility** for membranes and blood contact, **lower cost** ($15-30/kg vs PEI $25-50/kg). - **PEI/Ultem** ([Polyetherimide](/en/desktop/datos-de-resina/pei)) **wins on**: **HDT temperature** (200°C vs 205°C —technically similar but PEI holds better in dry air), **inherent FST** for aerospace (PES is also V-0 but FAR 25.853 certification is more established with Ultem), **chemical resistance to fuels** (Jet A, gasoline). **2026 rule**: for medical, membranes, baby bottles, parts that see hot water repeatedly → **PES**. For aerospace interiors and high-frequency connectors → **PEI**.
**Reusable high-temperature non-teflon cookware**: containers that go to microwave and conventional oven up to 180°C, ovenable kids' kitchen kits, industrial-kitchen pitchers. **Advantages**: BPA-free, no migration to hot foods, repeated dishwasher resistance, durable. **Brands**: **Bormioli Rocco** some products, **Pyrex flexible** alternatives, **Lekue**. **Limitation**: PES is not **non-stick** (doesn't replace Teflon or non-stick ceramic), so used for containers and trays, not pans.
**Yes, improves on hydrolysis and bases but similar to PSU in organics**: - **PES resists better**: continuous boiling water, water vapor, concentrated caustic bases (50% hot NaOH), hot diluted acids. - **PES similar to PSU in**: alcohols, aliphatic hydrocarbons, ketones (both attacked by acetone/MEK), chlorinated solvents (both dissolved by DCM). - **Doesn't resist**: concentrated mineral acids (96% H₂SO₄, oleum), concentrated ketones, aromatic hydrocarbons, esters. That's why PES is **superior to PSU for medical autoclave** (134°C steam multiple cycles) and continuous boiling water use.
**Yes, mechanically**, up to 25-30% regrind in industrial grades without significant loss. **It's thermally stable** —withstands multiple extruder passes. **Limitations**: for medical and filters (hemodialysis membranes), regrind isn't allowed for traceability and purity criticality. For industrial applications (connectors, baby bottles, cookware), 25% regrind is accepted without issues. PES is **chemically stable**, doesn't generate dioxins or HCl when melted like PVC —clean recycling.
**Bubbles and streaks from insufficient drying moisture** —same as PEI, PES is **hygroscopic** and absorbs moisture fast. If you process with moisture >0.05%, **silver streaks and micro-bubbles guaranteed**. Cure: 150°C × 4-6 h drying mandatory, desiccant dryer with dew point <-30°C, **don't open bags more than 1 hour before loading the hopper**. Second common issue: **cold mold generates stress** manifesting months later as **crazing** (surface microcracks) in transparent parts. Keep mold at 160°C+ always, and ideally post-mold anneal 1-2h at Tg+10°C (~235°C) for critical parts.

Sources

Discussion (0)