Alternative and trade names
Udel®, Ultrason® S


An amorphous, transparent and pale amber high performance thermoplastic, similar to PES. It offers very good radiation resistance, good chemical and hydrolysis resistance and low ionic impurity levels. It has slightly lower temperature resistance than PES, but does offer lower moisture absorption levels than PES, although drying is still essential before thermoforming. It has poor fatigue characteristics and is prone to environmental stress cracking but has good long term thermal ageing resistance. Its chemical resistance is also very similar to PES.



Density ρ

1.24 g/cm³ at 20 °C

Limiting oxygen index LOI

30 % at 20 °C

Water absorption, equilibrium cwater,equib

0.4 % at 20 °C


Elastic modulus E

2.48 GPa at 20 °C

Elongation A

50 - 100 % at 20 °C

Hardness, Rockwell M HRM

91 [-] at 20 °C

Impact strength, Izod notched IIzod,not

69 kJ/m² at 20 °C

Tensile strength Rm

70 MPa at 20 °C


Coefficient of thermal expansion α

5.6E-5 1/K at 20 °C


UL 94 - HB

Heat deflection temperature, 1.80 MPa HDT1.8,MPa

174 °C

Max service temperature Tmax

150 - 180 °C


Dielectric constant, 1MHz εr,1MHz

3.1 [-] at 20 °C

Dielectric strength EDS

17 kV/mm at 20 °C

Dissipation factor, 1MHz ε''1MHz

5E-3 [-] at 20 °C

Electrical resistivity ρel

5.00E+14 Ω·m at 20 °C

Technological properties

Application areas

Applications include use in food processing equipment such as milking machines, pumps, valves, filtration plates, heat exchangers and various medical components requiring repeated steam sterilisation.


Chemical Resistance: Acids (concentrated) Fair, Acids (dilute) Good, Alcohols Good, Alkalis Good, Aromatic hydrocarbons Fair, Greases and Oils Good, Halogens Good, Ketones Poor

Radiation resistance


UV resistance


This material data has been provided by Goodfellow.

All metrics apply to room temperature unless otherwise stated. SI units used unless otherwise stated.
Equivalent standards are similar to one or more standards provided by the supplier. Some equivalent standards may be stricter whereas others may be outside the bounds of the original standard.