Polyether sulfone (PES), usually an amorphous polymer. Compared with polysulfone, polyether sulfone has higher heat resistance and rigidity, its Tg is 225℃, and the thermal deformation temperature is 203℃. The mechanical properties are basically unchanged at 200℃. Polyether sulfone has excellent creep resistance and dimensional stability at high temperature. After adding 30% glass fiber reinforcement, the deformation under high load at 200℃ for 4 months is less than 0.005%. If half of the tensile strength is taken as the continuous service life, the polyether sulfone can be used for 20 years at 180℃ and 5 years at 200℃. Therefore, the long-term use temperature of polyether sulfone is 180℃, and 200℃ if 30% glass fiber reinforcement is added.

The mechanical properties of polyether sulfone are the highest among thermoplastics. For example, the tensile strength is 84.3MPa, the bending modulus is 2.65GPa, the elongation at break is 5-6% and the notch impact strength is 91J/m.

Polyether sulfone has excellent drug resistance to acid, alkali and other inorganic drugs and solvents, but can not resist strong polarity of organic solvents such as ketones, esters, halogenated hydrocarbons, dimethyl sulfone and so on. At high temperature, these organic solvents will promote residual stress leading to stress cracking, so glass fiber reinforced polyether sulfone should be used in this environment.

The impact strength of polyether sulfone, in the absence of notches, is equivalent to that of polycarbonate. But in the case of notch, notch radius has a great influence on impact strength. The smaller the notch radius, the lower the impact strength.

Polyether sulfone has excellent electrical properties and stable insulation performance at 200℃.

Compared with polysulfone, polyether sulfone has better melting processability and lower melt viscosity, small shrinkage (only about 0.6%), and good dimensional stability. However, polyether sulfone is more absorbent than polysulfone, so drying before forming is more important.