Take BASF as an example to talk about the performance, processing and application of three polysulfo2018-07-25
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Polysulfone plastic products
Polysulfone first appeared in the 1960s and is a thermoplastic resin containing a hydrocarbyl-SO2-hydrocarbyl group in the main chain of the molecule; the English name Polysulfone (referred to as PSF or PSU). Polysulfones are common bisphenol A type PSUs (so-called PSUs), polyphenylsulfones and polyethersulfones. Correspondingly, BASF has developed derivatives of these three substances: UItrason? S (bisphenol A polysulfone), UItrason? P (polyphenylsulfone) and UItrason? E (polyethersulfone).
I. Comparison and theoretical analysis of molecular formula of polysulfone
1. The molecular formula of ordinary bisphenol A type PSU:
The conjugation effect of the sulfone group provides oxidation resistance and thermal stability; the ether chain improves the toughness, and the benzene ring guarantees its mechanical strength and modulus.
2. The molecular formula of polyphenylsulfone PPSU:
The benzene ring on the polyphenylsulfone backbone provides high heat and mechanical properties; the ether linkage provides excellent flow and processing properties.
3. The molecular formula of polyethersulfone PESU:
The ether group provides flexibility and high flow, the sulfone group provides a heat resistant type, and the phenylene provides rigidity.
PSU is a slightly amber, amorphous transparent or translucent polymer with excellent mechanical properties, high rigidity, wear resistance, high strength, and excellent mechanical properties even at high temperatures. Its range is It is -100~150 °C, the long-term use temperature is 160 °C, and the short-term use temperature is 190 °C. In addition, PSF also has excellent properties such as high thermal stability, hydrolysis resistance, dimensional stability, small molding shrinkage, non-toxicity, radiation resistance, flame resistance, and extinguishability.
The table below compares the performance of these three polysulfones:
Table 1: Comparison of properties of bisphenol A polysulfone, polyaryl sulfone, polyether sulfone
2. Bisphenol A type polysulfone
English name: polysulfone
Abbreviation: PSU (PSF)
Bisphenol A type polysulfone is prepared by polycondensation reaction using bisphenol A and 4,4'-dichlorodiphenyl sulfone as raw materials. The bisphenol A type polysulfone can be regarded as a linear high molecular polymer which is linked by an isopropylidene group, an ether group, a sulfone group and a phenylene group. The sulfur atom of the bisphenol A type polysulfone is the highest oxidation state, and all the chains in the molecule are not easily hydrolyzed, and are resistant to acids and alkalis. It is soluble in polar solvents such as N,N-dimethylacetamide.
1. Performance analysis of bisphenol A polysulfone
1) Mechanical properties
Bisphenol A type polysulfone has excellent mechanical properties, and its tensile strength and bending degree are higher than that of general engineering materials. The mechanical properties retention rate under high temperature conditions is high, and the impact strength does not change within the range of -60 to 120 °C. Big.
The main disadvantages of bisphenol A type polysulfone are: poor fatigue resistance and internal stress cracking.
2) Thermal performance
Bisphenol A type polysulfone has excellent heat resistance as shown in Table 1:
Table 1: Thermal properties of bisphenol A polysulfone
3) Electrical performance
Bisphenol A polysulfone has excellent electrical properties over a wide range of temperatures and frequencies, with little change in electrical properties in water and humid air.
4) Chemical resistance
Bisphenol A type polysulfone has good chemical stability and is stable to inorganic acids, alkalis and salt solutions, but it is corroded by certain polar organic solvents such as ketones, halogenated hydrocarbons and aromatic hydrocarbons.
5) Other performance
Bisphenol A type polysulfone has excellent radiation resistance, but has poor weather resistance and ultraviolet resistance; its water absorption is 0.22%, the molding shrinkage is 0.7%, the dimensional stability is good, and its dimensional change is small under moist heat conditions.
2. Molding and processing properties of bisphenol A polysulfone
Bisphenol A type polysulfone can be formed by various methods such as injection, extrusion, blow molding, and rotation. The specific processing performance is as follows:
1) Bisphenol A type polysulfone is not sensitive to shear rate during molding, has high viscosity, low molecular orientation in melt flow, easy to obtain uniform product, easy to adjust specifications and shape, suitable for extrusion Forming and processing shaped products.
2) The bisphenol A type raw material must be sufficiently dried before molding, otherwise bubbles or silver filaments will appear on the surface of the product. Generally, the raw material moisture content is about 0.3%, and it must be dried to 0.05% or less. The lower corner material can be recycled after being crushed and dried.
3) When designing the mold, care should be taken to minimize the resistance of the melt flow. When using high temperature and high pressure injection molding, the material flow should be the shortest. The diameter of the injection nozzle should be greater than 3mm. When the product size reaches 100mm, the diameter of the injection nozzle should be greater than 4mm.
At present, PSU is mainly used for electronic and electrical aspects. The development of electronics and electrical to small, lightweight and high temperature has promoted the growth of PSU consumption. The demand for PSU in automobiles, aerospace, medical care and sanitation is still maintaining a steady growth momentum.
three. Polyphenylsulfone (polyphenylene ether sulfone)
English name: ployarylsulphone
Polyphenylsulfone is formed by polycondensation of a biarylsulfuryl chloride with an aromatic ring, and its applications are mainly in the electrical, electronic and automotive industries.
1. Performance analysis of polyphenylsulfone
1) Thermal performance
High heat resistance: no mechanical properties below 200 °C, no cracking at -150 °C at low temperature; Tg is 225 °C, Td> 203 °C.
2) Mechanical properties
Mechanical properties are excellent in thermoplastics, as shown in the following table:
Table 2: Mechanical properties of polyphenylsulfone
3) Flame retardancy
It is difficult to burn, and it can be tested with a sample with a thickness of 0.5mm, which can reach the UL94V-0 standard; the amount of smoke is small when forced combustion.
4) Chemical resistance
It has excellent chemical resistance to inorganic drugs and solvents such as acid and alkali; but it is soluble in extremely strong organic solvents such as dichloroethane and N-methylpyrrolidone.
5) Electrical performance
Excellent electrical properties, stable insulation at 200 ° C.
2. Processing properties of polyphenylsulfone
Processed into articles using injection, extrusion or compression molding techniques. However, polyphenylsulfone has a high melt viscosity and requires special processing equipment.
four. Polyethersulfone (polyaryl ether sulfone)
English name: polyether sulfone
1. Performance analysis of polyethersulfone
Table 3: The temperature of the use of polyethersulfone
2. Processing properties of polyethersulfone
With injection molding, extrusion, blow molding, compression molding or vacuum forming, high mold temperatures help to shape and reduce stress caused by molding.
Injection molding temperature: 310 ~ 390 ° C
Mold temperature: 140～180°C
PESU is an amorphous resin with a low mold shrinkage and can be processed into products with high tolerance and thin wall.
3. Application fields of polyethersulfone
Polyethersulfone has unique design properties: high mechanical properties in a wide temperature range (-100 ~ 200 ° C), high heat distortion temperature and good heat aging resistance, long-term use temperature up to 180 ° C, good weather resistance, flame retardant And low smoke density, good electrical properties, transparency and so on.
Therefore, PESU products are widely used in electrical, electronic, mechanical, medical, food and aerospace fields.
V. Application examples of BASF's UItrason? series
Ultrafiltration membrane module
Handheld coffee machine
Fog lamp housing
Pump thruster (arrow)
Fire helmet mask
Carbon fiber composite material
Hollow fiber membrane