Performance and Characteristics of Polyethersulfone(PES) and the Filter Membrane
Polyethersulfone is prepared by condensation of 4,4′-bissulfonyl chloride diphenyl ether with diphenyl ether catalyzed by anhydrous ferric chloride. The refractive index is 1.85, the glass transition temperature is 225°C, and the heat distortion temperature is 203°C (1.82MPa). PES has excellent aging resistance and can be used for up to 20 years at 180°C. PES has good flame resistance and does not emit smoke even if it burns. The creep resistance is good, the strain under 150℃ and 20MPa pressure is only 2.55%.
Mechanical performance of PES
Polyethersulfone (English abbreviation PES) is usually an amorphous polymer. Compared with polysulfone, polyethersulfone has higher heat resistance and rigidity, with a Tg of 225°C and a heat distortion temperature of 203°C. The mechanical properties remain basically unchanged at 200°C.
PES has excellent creep resistance and dimensional stability at high temperatures. After adding 30% glass fiber reinforced, the deformation of 4 months under 200℃ high load is less than 0.005%. If the tensile strength is reduced by half as the continuous service life, polyethersulfone can be used for 20 years at 180°C and 5 years at 200°C. Therefore, the long-term use temperature of polyethersulfone is 180°C, and if 30% glass fiber is added, it is 200°C.
The mechanical properties of polyethersulfone are among the highest among thermoplastics. For example, the tensile strength is 84.3MPa, the flexural modulus is 2.65GPa, the elongation at break is 5-6%, and the notched impact strength is 91J/m.
Polyethersulfone has excellent chemical resistance to inorganic chemicals and solvents such as acids and alkalis, but cannot withstand strong polar organic solvents such as ketones, esters, and halogenated hydrocarbons, and dimethyl sulfoxide. At high temperatures, these organic solvents will promote residual stress to induce stress cracking, so glass fiber reinforced polyethersulfone should be used in this environment. The impact strength of polyethersulfone is equivalent to that of polycarbonate without notches. However, in the case of a gap, the impact strength of the gap radius has a great influence. The smaller the notch radius, the lower the impact strength.
Polyethersulfone has excellent electrical properties and stable insulation performance at 200°C. Compared with polysulfone, PES has better melt processability and lower melt viscosity, low molding shrinkage (only about 0.6%), and good dimensional stability. However, the water absorption of polyethersulfone is greater than that of polysulfone, so drying before molding is more important.
PES filter membrane
The pores of the Hydrophobic polyethersulfone filter membrane account for more than 80% of the membrane volume. The micropore opening rate has unique micropores. The geometric shape improves the filtration efficiency and flow rate of the solution that is difficult to filter. Made of polyethersulfone and polypropylene and combined with hot melt and without adhesive, the PES filter membrane can be applied to such industries with stricter requirements as the chemical and pharmaceutical industries.
The unique hydrophilic properties, without surfactants and surface lubricants, provide a high level of filtration accuracy and throughput for filtered solutions, a wide applicable pH range, low adsorption capacity. Also, PES filter membrane features a high retention rate, good strength, good thermal stability, and resistance to chemical and forward/reverse pressure shocks. The production process adopts unique hot-melt welding processing technology, without any adhesive, no precipitation, and no pollution to the filter medium. PES filter membrane has high safety and a wide range of applications.
Pharmaceutical industry: terminal sterilization filtration for injection, water for injection, eye drops, non-high temperature sterilizable products, biological products, vaccines, serum, etc.
Food industry: filtration of alcohol, mineral water, drinking water, beverages, etc.
Electrical industry: terminal filtration of high-purity water, ultra-pure water equipment, chemical raw materials, etc.
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