Sulfone Polymers Overview

Sulfone polymers are high-heat plastics with a clear advantage. These amorphous thermoplastics offer more toughness, strength and hydrolytic stability than other transparent plastics.


Sulfone polymers are high-heat plastics with a clear advantage. These amorphous thermoplastics offer more toughness, strength and hydrolytic stability than other transparent plastics. They withstand prolonged exposure to water, chemicals and temperatures – handling a broad range of end-use temperatures from -40°C to 204°C (-40°F to 400°F).

Udel® PSU – Rigid, high-strength, semi-tough, transparent plastic that offers higher heat resistance and better hydrolytic stability than polycarbonate (PC). It retains its good mechanical properties when exposed to steam and other sterilization techniques.

HDT of 174°C (345°F), Good practical toughness, Good chemical resistance. 

Radel® PPSU – Delivers the highest performance of our sulfone polymers, offering better impact resistance and chemical resistance than polysulfone (PSU) and polyetherimide (PEI).

HDT of 207°C (405°F), Superior toughness and impact strength, Best chemical resistance, R-7000 Series for aircraft interiors. 

Acudel® modified PPSU – A family of proprietary formulations that fill the cost-performance gap between PPSU and polysulfone (PSU).

HDT of 197°C (387°F), Better impact strength than PSU, Excellent long-term hydrolytic stability. 

Veradel® PESU – Combines good chemical resistance with a high heat deflection temperature of 204°C (399°F), making it a good fit for food service applications. This resin is also inherently flame retardant for use in electronic components and testing devices

HDT of 204°C (399°F), Better chemical resistance than PSU, Inherently flame retardant. 

Virantage® Tougheners – Comprehensive range of specialty polymers, oligomers and monomers in a variety of molecular weights and particle sizes. Product forms include powders, fibers and foams. High-temperature tougheners, Improves damage tolerance, Reactive end groups available.


Good-Better-Best Performance Capabilities

  Udel® PSU Veradel® PESU Acudel® mod. PPSU Radel® PPSU Virantage® PESU
Performance Good Better Better Best Specialty
Aircraft Interiors     X X  
Coatings   X   X  
Composites         X
Electrical & Electronics X X      
Fittings & Manifolds X   X X  
Faucet Components X   X X  
Food Service   X X X  
Fuel Systems       X  
Membranes X X   X  
Medical & Dental Devices X     X  
Orthopedics       X  
Sterilization Cases & Trays       X  


Sulfone polymers are noted for high heat deflection temperatures (HDT) and outstanding dimensional stability. These strong, rigid polymers are the only thermoplastics that remain transparent at service temperatures as high as 204°C (400°F). Even after long-term exposure, the resins do not discolor or degrade.


The hydrolytic stability of sulfone polymers makes them highly resistant to water absorption. This combines with heat resistance to deliver reliable long-term performance in hot water and steam, even under autoclave pressures. Unlike other transparent polymers, sulfone polymers are not prone to clouding or crazing.

Retention of Tensile Strength in 96°C Water



Retention of Tensile Strength in 132°C Water for 30 Minutes


Sulfone polymers are extremely tough and do not break in standard unnotched impact tests. They retain their toughness and strength over time, unlike polyetherimide (PEI) which exhibits a significant loss of impact strength and becomes brittle.

Retention of Tensile Strength



Retention of Impact Strength



The impact strength of test plaques heat aged at 190°C (375°F) for 170 hours was evaluated using a Gardner falling dart impact tester. Radel® PPSU absorbs significantly higher impact force than polyetherimide (PEI) without cracking or breaking.


Falling Dart Impact Test


Sulfone polymers have good chemical resistance to many materials, including the following:

  • Aqueous systems
  • Caustics
  • Inorganic acids
  • Aliphatic hydrocarbons
  • Detergents and soaps
  • Certain alcohols


General Indication of Chemical Resistance

  Udel® PSU Radel® PPSU PC
General Chemicals      
Alcohols Good Excellent Good
Acids, Concentrated Good Excellent Fair
Acids, Diluted Excellent Excellent Good
Bases, Concentrated Excellent Excellent Poor
Baes, Diluted Excellent Excellent Poor
Esters Poor Fair Poor
Hydrocarbons, Aliphatic Excellent Excellent Poor
Hydrocarbons, Aromatic Poor Fair Poor
Hydrocarbons, Chlorinated Poor Fair Poor
Ketones Poor Poor Poor
Hospital Disinfectants      
Bleach Solutions, 10% Excellent Excellent Good
Cavicide® Excellent Excellent Good
Envirocide® Excellent Excellent Good
Cidex® Excellent Excellent Excellent
Hydrogen Peroxide, 3% Excellent Excellent Good
Isopropyl Alcohol, 70% Good Excellent Good
Manu-Klenz® Excellent Excellent Excellent
Phenols, 2% Poor Excellent Good
Quaternaries Good Excellent Excellent
Sani-Cloth® HB Excellent Excellent Poor
Sani-Cloth® Plus Poor Excellent Poor
Sporotal® 100 Good Excellent Excellent
Wex-Cide® Poor Excellent Good


Udel® PSU and Radel® PPSU are compatible with a full range of commercial sterilization technologies. Because of its high heat resistance and excellent hydrolytic stability, Radel PPSU can be steam sterilized over 1,000 cycles without any significant loss of properties.



The Solvay family of Sulfone polymers offer transparent, opaque and glass-fiber reinforced grades in natural and colored resins.

Sulfone polymers are the only thermoplastics that remain transparent at temperatures as high as 204°C (400°F). Even after long-term exposure to elevated temperatures, the materials do not discolor or degrade.

The resin’s natural color is transparent light amber. Low-color grades of Udel PSU with a near water-white appearance are available. Solvay uses its proprietary low-color technology to create vibrant transparent colors that give OEMs a clear advantage over metal without compromising performance.

Veradel® PESU and Radel® PPSU are inherently flame retardant. Radel R-7000 Series products are specially formulated for us in aircraft interiors and are in compliance with stringent FAA regulations requiring low heat release, low smoke generation and low toxic gas emissions.