Polyphenylsulfone (PPSF/PPSU): Quick Quotes and Worldwide Delivery

Polyphenylsulfone (PPSU/PPSF) – properties, uses and sourcing

Polyphenylsulfone, widely known under the trade names PPSU or PPSF, is one of the highest‑performing members of the sulfone family of polymers. The polymer’s backbone consists of aromatic rings linked by sulfone (–SO₂–) groups. This structure gives polyphenylsulfone exceptional thermal and chemical stability. The material was commercialised under Union Carbide’s Radel® trademark in the mid‑1970s; the trademark filing, made on 1 October 1976 and registered on 17 May 1977, marks the birth of the PPSU market. Today, Solvay’s Radel® brand still offers a range of grades, such as R‑5000, R‑5100 and R‑5500, tailored for specific processing requirements.

Molecular structure and identification

Polyphenylsulfone belongs to the polysulfone family but differs from traditional polysulfones (PSU) because its repeating unit contains a biphenyl group rather than an isopropylidene bridge. The aromatic sulfone structure makes the polymer amorphous—there is no true melting point—and provides rigidity at low temperatures down to –240 °C. The base polymer is listed by ChemicalBook under CAS No. 25608‑64‑4 and is described as 1,1‑biphenyl‑4,4′‑diol polymerised with 1,1′‑sulfonyl‑bis(4‑chlorobenzene); common synonyms include polyphenylsulfone and poly[oxy(1,1‑biphenyl)‑4,4′‑diyloxy‑1,4‑phenylenesulfonyl‑1,4‑phenylene].

Core properties of PPSU

Thanks to its aromatic sulfone structure, PPSU offers a unique combination of thermal, mechanical and chemical properties:

• High heat resistance – injection‑moulded PPSU maintains mechanical integrity at continuous‑use temperatures up to 260 °C and has a heat‑deflection temperature around 196 °C (ISO 75). Radel® grades list HDT values of 207 °C.

• Mechanical strength – typical unfilled grades have a tensile strength of 70–75 MPa and flexural strength around 105 MPa; the material’s toughness is evidenced by notched‑Izod impact values of ~3.8 J cm⁻¹. Tuntun Plastic notes that PPSU’s tensile strength can reach 70 MPa (10,152 psi).

• Dimensional stability – the polymer’s high modulus (2.3–2.7 GPa) and low moisture uptake (0.3–0.6 %) mean that parts maintain their shape under humidity or temperature fluctuations.

• Chemical and hydrolytic resistance – PPSU resists acids and bases and withstands aggressive disinfectants. It also tolerates more than 1,000 cycles of steam sterilisation at 134 °C without significant property loss, making it ideal for medical devices.

• Electrical insulation – the polymer has a high volume resistivity (~6×10¹⁵ Ω·cm) and a low dielectric constant (~3.46), so it serves as an excellent insulator in electronic connectors.

• Biocompatibility and safety – PPSU is BPA‑free and inert; Tuntun Plastic notes that it complies with ISO 10993, NSF, ACS, WARS, UL‑94, REACH and RoHS standards. This compliance, together with its ability to be sterilised repeatedly, explains why PPSU baby bottles are marketed as safer alternatives to polypropylene (PP) or polycarbonate bottles.

A small overview of typical properties is given in Table 1.

Advantages and limitations

The high heat resistance, chemical inertness, dimensional stability, impact strength and biocompatibility of PPSU make it attractive for demanding applications. Unlike commodity plastics, it can be repeatedly sterilised without degradation and maintains strength at boiling temperatures. However, designers should note two drawbacks: cost – PPSU is more expensive than engineering thermoplastics like ABS or nylon – and processability. Its amorphous nature gives it a high glass transition temperature (≈220 °C), which means melting requires precise temperature control and results in high melt viscosity. Skilled processing and drying are essential to avoid injection‑moulding defects.

Available forms and grades

BACH INDUSTRY AG supplies PPSU in various forms and grades to meet different processing needs. The base polymer is available as resin pellets or granules for injection moulding, filament for 3D printing and powder for additive manufacturing. Semi‑finished products include PPSU sheet, rod, tube and film, which can be machined or thermoformed for prototypes or small production runs. High‑performance membranes made from polyphenylsulfone provide excellent chemical resistance for filtration and dialysis applications.

Within the Radel® family, grades differ in flow characteristics and colour options. General‑purpose grades such as R‑5000 and R‑5100 are available in transparent or opaque colours. R‑5500 offers a low‑flow grade suitable for extrusion, while R‑5800 and R‑5900 provide medium‑ and high‑flow behaviour. Glass‑fibre‑reinforced grades (e.g., RG‑5010) deliver higher stiffness and dimensional stability.

Processing and fabrication

Injection moulding is the most common fabrication method. The recommended melt temperature is ~360 °C, and the material should be dried at 165 °C for about four hours to remove moisture. Uniform wall thicknesses (0.76–2.92 mm) and smooth transitions help avoid sink marks and voids. Rounded corners and appropriate draft angles are also important. PPSU can also be extruded into tubes or film, thermoformed or blow‑moulded for hollow parts. For additive manufacturing, PPSU filaments from suppliers such as 3DXTech are used in FDM printers; they require high nozzle temperatures (approx. 380–400 °C) and heated build platforms.

Applications

PPSU is used wherever strength, temperature resistance and chemical compatibility are critical:

• Medical and dental devices – repeated steam sterilisation and biocompatibility make PPSU ideal for instrument handles, surgical trays, implant trials and ventilator humidification tanks. The material’s impact strength and sterilisation resistance explain its popularity for dental and surgical instruments.

• Baby bottles and food‑contact products – PPSU baby bottles, feeding bottles, sippy cups and weighted straw cups are valued because the material is BPA‑free and can withstand repeated boiling or UV sterilisation. Its amber transparency allows parents to monitor contents, and the material does not release BPA or phthalates during use. Compared with polypropylene bottles, PPSU bottles tolerate higher temperatures, and they are lighter and shatter‑resistant compared with glass bottles.

• Plumbing fittings – PPSU tees, elbows and PEX components provide corrosion‑free alternatives to brass. In plumbing, Radel® PPSU fittings resist crack formation and serve reliably in hot‑water service.

• Aerospace and automotive – the combination of low flammability, high impact strength and colourability (for cabin interiors) makes PPSU suitable for aircraft interior panels and electrical connector housings. The polymer also appears in automotive coolant systems and pump components where resistance to hot water and glycols is important.

• Membranes and filtration – polyphenylsulfone membranes are used for water treatment and gas separation because of their chemical stability and ability to withstand cleaning agents.

Comparisons with other materials

Compared with polyetherimide (PEI), PPSU offers better impact strength and chemical resistance. Syensqo’s Radel® literature notes that the material combines impact strength similar to polycarbonate (PC) with better chemical resistance than PEI. While PEI and PSU can operate near 170 °C and 150 °C respectively, PPSU’s HDT of ~196–207 °C gives it a wider service window. Compared with polypropylene (PP), PPSU has far higher tensile strength and heat resistance, which is why PPSU bottles cost more but last longer. It also surpasses tritan and silicone in heat stability and sterilisation durability, although silicone remains more flexible. Relative to glass, PPSU bottles are lighter and shatter‑proof. In short, PPSU sits at the top of the sulfone family and delivers premium performance for demanding applications.

Safety, durability and sustainability

PPSU is inherently flame‑retardant and retains mechanical properties after long‑term exposure to hot water. Studies show that repeated sterilisation does not cause significant hydrolytic degradation, so the material has a long service life for baby bottles and medical devices. The polymer’s inertness reduces the risk of leaching additives, and its smooth, non‑porous surface resists biofilm formation. As an amorphous polymer, PPSU can be recycled through mechanical regrinding or re‑moulding; however, specialised facilities are required because of its high processing temperature.

Identifiers, pricing and where to buy

For procurement, the CAS number 25608‑64‑4 uniquely identifies unreinforced polyphenylsulfone. When evaluating the price of PPSU granules, sheet, rod or finished products, buyers should consider the grade (e.g., R‑5000 vs glass‑filled), form, and quantity. PPSU is generally more expensive than commodity plastics due to its complex synthesis and high processing temperature. Nevertheless, its long service life can lower the cost per use, especially for products subjected to frequent sterilisation.

BACH INDUSTRY AG is a reliable supplier of PPSU materials and components. We offer raw resin, granules, Radel® PPSU grades, glass‑filled composites and a wide range of semi‑finished products (sheet, rod, tube, film). Our product line also includes plumbing fittings, PEX components, baby bottles and other consumer goods made from PPSU. Customers can buy these materials directly from us, and we provide competitive pricing for large or small orders. We serve Switzerland, Germany, Austria, Liechtenstein, Belgium and Africa, ensuring prompt delivery and local support. Whether you need high‑temperature filament for 3D printing, PPSU fittings for hot‑water systems or PPSU baby bottles, our team will help you choose the right grade and customise the order to suit your needs.

Conclusion

Polyphenylsulfone (PPSU/PPSF) is a high‑performance thermoplastic that combines high temperature resistance, mechanical strength, hydrolytic stability and chemical inertness. Originally introduced under Union Carbide’s Radel® trademark in 1976, PPSU has evolved into many grades and forms for diverse applications—from medical devices and food‑contact products to plumbing fittings and aerospace components. Its superior properties justify a higher price tag, yet the material’s durability and safety make it a compelling choice for critical parts. With accurate identification via CAS 25608‑64‑4 and a clear understanding of its benefits and limitations, designers and manufacturers can confidently specify PPSU. BACH INDUSTRY AG stands ready to supply the material across Switzerland, Germany, Austria, Liechtenstein, Belgium and Africa, providing technical support and competitive pricing for your next project.