Polysulfone plastics refer to a class of polymers containing sulfone groups and aromatic nuclei on the macromolecular chain, which mainly includes three main varieties: bisphenol A-type polysulfone (referred to as polysulfone, referred to as PSF in English), polyaryl sulfone (PASF) and polyethersulfone (PES), among which (PSF) has the largest output and the most widely used.
1. Introduction to polysulfone
Polysulfone is the abbreviation of bisphenol A-type polysulfone, and the English abbreviation is PSF.
The most outstanding performance of PSF is good heat resistance, it can be used for a long time in the range of -100~150°C, and other mechanical properties, creep resistance, and electrical properties are very good. It is widely used in electronic appliances, auto parts, medical equipment and mechanical parts.
(1) Mechanical properties PSF has excellent mechanical properties, its tensile strength and bending strength are higher than those of general engineering plastics such as PC, POM, ABS, PA, etc., and the mechanical properties retention rate is high at high temperatures, and the impact strength changes little in the range of -60~120 °C. The creep resistance of PSF is very prominent, only 0.14%~0.20%, and the change is very small at higher temperature and large load.
(2) Electrical performance PSF has excellent electrical properties, with little change in water and humid air, and can still maintain good electrical properties at high temperature of 190°C.
(3) Thermal performance PSF has excellent heat resistance, outstanding thermal and oxidative aging resistance, and excellent self-extinguishing property.
(4) Environmental performance PSF is resistant to inorganic acids, alkalis and salts, not concentrated sulfuric acid and nitric acid, and can be corroded by polar organic solvents such as aromatic hydrocarbons, ketones and halogenated hydrocarbons. It has excellent radiation resistance, but poor weather resistance and ultraviolet resistance.
Molding processing and application
Due to the high rigidity, PSF leads to high melt viscosity and high flow temperature, and PSF fluid is close to Newtonian fluid, and the viscosity is sensitive to temperature and the shear rate has little influence on it.
PSF can be processed by injection molding and extrusion, and the PSF melt is not easy to stay for too long to avoid decomposition.
PSF products are mainly used in:
(1) Electronic and electrical PSF has excellent comprehensive performance and electrical insulation performance, and its heat resistance can reach class F in electricians, which belongs to a class of heat-resistant insulation materials, which can be used for integrated circuit boards that require a temperature of -100~160 °C. In addition, electrical appliances such as hand-held drill shells and battery packs, battery boxes, capacitor films and wires, cable sheaths, electroplating tanks, oscilloscope sleeves and coil frames, small precision electronic components, etc.
(2) Automotive industry PSF has excellent oil resistance, heat resistance, high rigidity, high strength and other properties, and can be used for automobile speed divider covers, guard plates, bearing cages, engine gear thrust rings and fender covers.
(3) Medical devices PSF can be widely used in the field of medical devices because of its good transparency, hot water and steam resistance, and good hygiene. Specific products include: gas masks, contact spectacle lenses, disinfection utensils, endoscope parts, artificial heart valves, ultrafiltration membranes and reverse osmosis membranes.
(4) Machinery industry Due to the high strength, low creep, water resistance and dimensional stability of PSF, it can replace a large number of non-ferrous metal materials such as copper, aluminum, zinc and lead in the machinery industry. Such as: watch cases and parts, photocopiers and camera parts, hot water valves in food processing machinery, cooling system devices and transmission parts, etc.
2. Introduction to polyarylsulfone
Polyarylsulfone is also known as aromatic polysulfone and polyphenylene ethersulfone, abbreviated as PASF in English.
Compared to PSF, PASF has a significant increase in strength and heat resistance, with a 25% increase in tensile strength, an increase in heat resistance to 260°C, and a short-term use at 300°C, which is nearly doubled. The hardness, creep resistance, and wear resistance are also higher than those of PSF. PASF has excellent resistance to acid, alkali and water vapor, and is stable to fuel oil, hydrocarbon oil, silicone oil and Freon, etc., and is resistant to various commonly used industrial solvents, but is not resistant to some polar solvents such as dimethylformamide, butyrolactone, etc.
PASF can be processed using general processing methods, but it is more difficult to process than PSF due to its high melt viscosity and flow temperature.
PASF is mainly used as a Class C insulating material in the electronic and electrical industry, making various high-temperature resistant coil frames, switches, connectors and distribution boards. In the machinery industry, PASF is blended with F4 or graphite to manufacture bearings used at high temperatures and high loads.
3. Introduction to polyethersulfone
Polyethersulfone is PES in English, which is an amber transparent amorphous plastic. Compared to PSF, PES has a slight improvement in strength and heat resistance. However, its creep resistance is extremely outstanding, and it is still excellent at higher temperatures and large loads. Resistant to acids, alkalis, salts, oils, greases, aliphatic hydrocarbons and alcohols, etc., and not resistant to polar organic solvents such as ketones, esters, chloroform, etc.
The transparency of PES is the best among polysulfone plastics, with a light transmittance of up to 88% and a refractive index of 1.62, which is the largest variety among transparent plastics and is suitable for manufacturing lenses.
The processing characteristics of PES are similar to those of PSF, the processing temperature is slightly higher than that of PSF, and it also needs to be dried before processing.
PES is mainly used in:
In the electronic and electrical industry, it can be used as an H-class insulating material, specifically used in printed circuit boards, coil skeletons, instrument housings, integrated circuit sockets, thyristor insulators and micro capacitor films (18% smaller than PET film capacitors and 23% smaller than PC films).
In the machinery industry, PES is used in the manufacture of piston rings, bearing cages, hot water measuring instruments, warm water pump housings and impellers.
In the auto parts industry, PES manufactures automotive gearbox components, lamp covers, fasteners, engine gears and ball bearing cages.
In the medical device industry, PES is used in steam disinfection equipment, artificial respirators, blood pressure examination tubes, syringes, ultrafiltration membranes and reverse osmosis membranes.
In the field of optics, PES can be used in eyewear materials, lampshades and endoscopes.
