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Virantage® PESU


High-temperature thermoplastics, such as Virantage® PESU, improve the toughness of epoxy systems while retaining high modulus, high temperature capability, hot-wet performance and resistance to aggressive environments.

Repeating unit for functionalized r-PESU


Discover all Virantage® PESU grades



The addition of high molecular weight Virantage® PESU leads to an increase in the viscosity of an epoxy solution. The change in viscosity depends on the concentration and molecular weight of the additive and may require some modifications to the subsequent composite preparation processes.

Solution Viscosity of PESU-TGAP* at 75 °C (167 °F)

*TGAP (triglycidyl-p-aminophenol)


Toughening Performance

The effect of varying the concentration of three Virantage® PESU grades on the fracture toughness (K1C) of a TGAP epoxy system cured with DDS (4, 4’-diamino-diphenyl sulfone) is shown in the figure below. As expected, the slightly higher molecular weight VW-10200 RP gives higher K1C values compared to the same loading with the lower molecular weight VW-10700 RP and implies more effective toughening. The non-functionalized VW-10300 P offers toughening capability up to certain loading levels.

Effects of PESU concentration and MW on fracture toughness for TGAP-PESU-DDS



Virantage® PESU tougheners can be added to a variety of commercial epoxy systems via several different methods. Virantage® PESU can be directly dissolved in a liquid epoxy system followed by the addition of a curing agent. It can also be dissolved in a number of solvents and then mixed with epoxy/hardener systems. Virantage® PESU may also be adducted with an epoxy using a catalyst followed by the addition of a hardener.

Virantage® PESU and other sulfone polymers can absorb small amounts of water and retain up to 2 % moisture at equilibrium. Although they are hydrolytically stable, it is best to dry them prior to processing to remove casual surface moisture. 

Virantage® PESU products are stable at room temperature and should be stored in a closed container. When preparing epoxy systems using Virantage® PESU tougheners, refer to the epoxy manufacturer’s product guidelines for storage and stability information.