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PPSU

Polifenilsulfona

PPSU·High Performance·Amorphous

PPSU (Polyphenylsulfone) is the "champion of the polysulfone family": amorphous, transparent amber, Tg of 220°C, HDT of 207°C, and the killer property no other plastic matches —tolerates over 1000 autoclave cycles at 132°C without losing properties, making it the #1 material for reusable surgical instruments. It's the "big brother" of the family, related to PES and PSU, but with a crucial chemical difference: its backbone contains biphenyl (-C₆H₄-C₆H₄-) instead of isopropylidene (PSU) or only ether groups (PES).

That biphenyl structure gives it two standout properties: exceptional impact resistance (the toughest of high-temp amorphous, doesn't crack even with cold impacts) and extreme hydrolysis resistance —where PSU hydrolyzes after 50 autoclaves, PPSU passes 1000 without issues. The dominant brand is Solvay/Syensqo Radel R (grades R-5000 standard, R-5100 instrumental, R-5500 for machining); BASF Ultrason P is the European alternative.

Flagship applications: reusable medical instruments (modular surgical kits, dental handles, sterilization trays), aerospace cabin interiors (overhead bins, ceiling panels, ducting), premium BPA-free baby bottles (leader in Asian market), dental drill housings. Processing-wise: drying 150°C × 4-6h, melt 340-380°C, hot mold 140-180°C. Cost $25-50/kg —between PEI above and PSU/PES below. Are you running Radel? Share your experience with repeated 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)1.43:1
L/D Ratio18 – 24
Compression Ratio1.5 – 2.5
Tonnage Factor3.09 – 6.18kN/cm²
Thermal Diffusivity0.2074mm²/s
Max Shear Rate50,0001/s
Shrinkage0.7 – 0.9%
Regrind❌ Not allowed
Heat Deflection (HDT) @ 1.82 MPa207°C
Glass Transition (Tg) @ 10°C/min220°C
Vicat Softening @ 50N205°C

Drying

Drying Temperature129 – 149°C
Drying Time3 – 4h
Recommended Moisture0.04%
Recommended Dryer TypeDesiccant
Dew Point-40°C

Temperatures

Melt343 – 377°C
Nozzle368 – 374°C
Front368 – 374°C
Middle360 – 374°C
Rear349 – 374°C
Demolding152 – 188°C
Mold (Cooling)135 – 177°C
Feed Throat35 – 79°C

Processing

Back Pressure1.7 – 5.2bar
Screw Speed30 – 60RPM
Injection SpeedMedium
Barrel Occupancy30 – 70%
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 – 0.0406mm
Land (Vent Land)0.762 – 1.52mm
Width (Vent / Clearance)4.06 – 10.2mm
Relief (Relief Channel)0.2032 – 0.4064mm

Frequently asked questions

**PPSU** (Polyphenylsulfone, also written **PPSF**) is an aromatic amorphous thermoplastic with a backbone alternating **sulfone groups** (-SO₂-) and **biphenyl** (-C₆H₄-C₆H₄-) instead of PSU's isopropylidene (-C(CH₃)₂-). That chemical difference is huge: - **PSU** (Polysulfone): isopropylidene + sulfone. Tg ~190°C. Cheaper and easier to process but lower performance. - **PES** ([Polyethersulfone](/en/desktop/datos-de-resina/pes)): ether + sulfone. Tg ~225°C. Better temperature. - **PPSU**: **biphenyl** + sulfone. Tg ~220°C, **better impact** and **better hydrolysis** than both siblings. The biphenyl structure blocks molecular movements that would generate cracks, translating into superior toughness and chemical stability.
For a unique property combination: - **(1) 1000+ autoclave cycles at 132°C** without significant property loss —the record among plastics. PSU handles 100-200, PC less than 50. - **(2) Outstanding impact strength**: instruments fall to floor, don't crack. PSU and PEI fracture at low temperatures; PPSU doesn't. - **(3) Disinfectant compatibility**: bleach, alcohols, vaporized hydrogen peroxide (VHP), all pass without attacking the material. - **(4) Biocompatibility** USP Class VI, ISO 10993, ISO 11135 (EtO sterilization). - **(5) Multiple sterilization**: steam, EtO, gamma, plasma, VHP —all OK without visible degradation. **Leading brands**: Karl Storz, Stryker, Aesculap use PPSU in retractor handles, orthopedic kits, sterilization trays, dental scalers.
- **Drying**: **150°C × 4-6 h mandatory**, desiccant dryer with dew point <-30°C. Final moisture <0.02%. - **Melt**: **340-380°C** (standard Radel 360°C). Window narrower than PSU because melt viscosity is higher. - **Mold**: **140-180°C mandatory** —ideally 160-180°C for maximum properties and minimum residual stress. - **Residence**: <10 min. Sustained >380°C starts degrading. - **Injection speed**: medium. PPSU's high melt viscosity requires **high torque** in machine —not recommended to inject PPSU in machine designed for commodity PE/PP.
**Reasons that positioned it as polycarbonate replacement in premium bottles**: - **BPA-free**: doesn't contain bisphenol-A. PPSU has biphenyl but **not hydrolyzable to BPA** —key difference vs PC. - **Resists 1000+ steam or boiling-water sterilization cycles** without yellowing or losing transparency (vs PC which yellows at 200-300 cycles). - **Superior impact resistance** —doesn't break if baby throws it. - **Natural pale amber color** —more yellow than PES, less than PEI. Some brands market as "natural amber color". - **FDA approved** and EU for prolonged direct food contact. **Premium brands**: Hegen (Singapore), Comotomo, Spectra, b.box, Pigeon premium series use PPSU. **Limitation**: higher cost than PP (3-5×) and PES (1.5-2×).
**Cabin interior replacing heavy metal or composites**: - **Overhead bins and panels**: thermoformed PPSU for overhead luggage compartments. Resists repeated impact, meets FAR 25.853. - **Ceiling panels and bezels**: ductwork for air conditioning, in-flight screen frames. - **Seat back panels** in some premium brands (Recaro Aircraft, B/E Aerospace). - **Lavatory components**: combination of impact resistance + steam sterilization compatibility is ideal. Vs PEI: PPSU has less modulus stiffness but **higher impact** and **better tolerance to cleaning chemicals** (aerospace lavatory uses aggressive chemicals daily).
**Shrinkage 0.6-0.8% isotropic** —slightly higher than PSU (0.5-0.7%) and PES (0.5-0.7%). The biphenyl structure makes the chain pack slightly more, generating somewhat more shrinkage on cooling. With 20% GF: drops to 0.3-0.5%. Predictability remains good as it's amorphous.
Both are amorphous transparent amber, high-temperature, V-0. Critical differences: - **PPSU wins on**: **impact** (drop resistance), **hydrolysis** (repeated autoclave), **medical toxicological track record** (longer history in implants and devices). - **PEI** ([Polyetherimide](/en/desktop/datos-de-resina/pei)) **wins on**: **higher HDT** (200°C vs 207°C —technically PEI is slightly lower but more stable in dry air), **inherent FAR 25.853 certified FST** (PEI has better aerospace track record), **slightly lower cost**. **2026 rule**: for reusable medical seeing water/steam → **PPSU**. For dry reusable medical + aerospace interiors → **PEI**.
**Yes, it's one of few plastics resistant to the full list**: - **Resists**: sodium hypochlorite (bleach 0.5-10%), hydrogen peroxide (3-35%), alcohols (ethanol, isopropanol), glutaraldehyde, peracetic acid, quaternary ammonium, VHP (vaporized peroxide). - **With limitations**: enzymatic detergents (OK but requires rinsing), benzalkonium. - **Doesn't resist**: chlorinated solvents (methylene chloride, chloroform —dissolve it), concentrated toluene, MEK. This compatibility profile is what makes it standard in **CSSDs (Central Sterile Supply Departments)** and for hospital processing with **automated washers**.
**Mechanically yes** up to 25% regrind in industrial without significant loss. **Thermally stable** —withstands multiple extruder passes. **Limitations**: for reusable medical and implants, regrind not allowed for traceability. For industrial applications (cookware, baby bottles, technical parts), 20-25% regrind is accepted. PPSU is **chemically stable** —doesn't generate halogens when melted like PVC— but the **post-consumer recycling market** is practically zero because most PPSU is captive in medical/aerospace with their own programs.
**In-service stress-cracking from high residual stress** —if you mold with cold tool (<140°C), the part has frozen tensions manifesting **months later** as spontaneous cracks (especially when exposed to chemicals or thermal cycles). **Cure**: - Uniform hot mold **160-180°C** mandatory. - **Moderate injection speed** —avoid excessive shear orienting chains. - **Post-mold annealing** for critical parts: 2-4 h at 200°C in air oven (relieves stress, improves performance). - Mold design without **adjacent thick-thin sections** generating cooling differential. Second common issue: **insufficient drying** → silver streaks (same as entire sulfone family).

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