Polyarylsulfone

Polyarylsulfone (PAS) thermoplastics have relatively low melt-processing temperatures, considering their high mechanical properties. For one thing, they are hydrolytically stable. They have a heat-distortion temperature at least 204°C (400 F) at 1,820 kPa (264 psi), tensile strengths to 124 MPa (18,000 psi) or better, and a flexural modulus up to 1.17 X 10 psi. Under stress they are highly resistant to mineral acids and alkali and salt solutions. Their applications are in electrical and electronic items, frozen-food packaging, and aircraft interiors. 

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Amorphous Thermoplastics. Polysulfone, polyethersulfone, and polyarylsulfone are examples of amorphous thermoplastics. These materials have high Ts and can stand temperatures up to 200°C for a long period of time. Amoco and ICI are principal suppHers of this class of material. 

Polysulfone Resins. Commercially important polysulfones are aromatic, ie, in the generalized formula for the repeating unit R and R both contain aromatic rings (see Polymers containing sulfur, polysulfone resins). They all possess ether linkages as weU, so that use of the designations polysulfone, polyarylsulfone (PAS), and polyethersulfone (PES) is somewhat arbitrary. 

Union Carbide introduced the first commercial polyarylsulfone resin, Udel, in 1966 and later introduced Radel polyarylsulfone. The business and patents rights were acquired by Amoco Corp. in 1986. Other polysulfone products have been marketed by BASF and ICl (Victrex PES) the latter aimounced in 1991 it was withdrawing from the business. 

Radel A 400 polyarylsulfone lesin is made from a piopiietaiy blend of bisplienols (believed to include hydioquinone) and dichloiodiphenyl sulfone. Victiex lesin is made by other displacement reactions. 

Amoco Performance Products (Atlanta, Ga.), is the sole supplier of polysulfone, Udel, polyarylsulfone, Radel A, and polyphenylsulfone, Radel R. ICI Advanced Materials (Exton, Pa.), is the sole domestic supplier of the polyethersulfone, Victrex PES, but announced ia 1991 it was withdrawing from the business. 

The first commercial polymer Table 21.3, II) was offered in 1965 by Union Carbide as Bakelite Polysulfone, now renamed Udel. In 1967 Minnesota Mining and Manufacturing introduced Astrel 360 Table 21.3, V), which they referred to as a polyarylsulfone. In 1972 ICI brought a third material onto the market which they called a polyethersulphone (III) and which they then marketed as Victrex. They also introduced a material intermediate between III and V known as Polyethersulphone 720P (IV) but which has now been withdrawn. In the late 1970s Union Carbide introduced Radel (VI), which has a higher level of toughness. Around 1986 Union Carbide sold their interest in polysulphones to Amoco. In addition the Astrel materials were produced by Carborundum under licence from ICI. 

Polysulfone It is a high performance amorphous plastic that is tough, highly heat resistant, strong and stiff. Products are transparent and slightly clouded amber in color. Material exhibits notch sensitivity and is attacked by ketones, esters, and aromatic hydrocarbons. Other similar types in this group include polyethersulfone, polyphenyl-sulfone, and polyarylsulfone. Use includes medical equipment, solar-heating applications and other performance applications where flame retardance, autoclavability and transparency are needed. 

Polysulfone, polyarylsulfone, polyethersulfone, polyphenylenesulfone, (PSU, PAS, PESU, PPSU)... 

The polyarylsulfone family comprises three chemical entities ... 

The magnitude of n is related to the density of the substance and varies from 1.000 and 1.3333 for vacuum and water, to about 1.5 for many polymers and 2.5 for white pigment, titanium (IV) oxide (titanium dioxide). The value of n is often high for crystals and is dependent on the wavelength of the incident light and on the temperature. It is usually reported for the wavelength of the transparent sodium D line at 298 K. Typical refractive indices for polymers range from 1.35 for polytetrafluoroethylene to 1.67 for polyarylsulfone. 

Polyarylsulfones offer materials with good thermal-oxidative stability, solvent resistance, creep resistance, and good hydrolytic stability. Their low flammability and smoke evolution encourage their use in aircraft and transportation applications. They hold up to repeated steam sterilization cycles and are used in a wide variety of medical applications such as life support parts, autoclavable tray systems, and surgical and laboratory equipment. Blow-molded products include suction bottles, surgical hollow shapes, and tissue culture bottles. PPS has a number of automotive uses including as an injection-molded fuel line coimector and as part of the fuel filter system. 

Aromatic polymers such as PS are readily attacked by chlorine bromine, concentrated sulfuric acid, and nitric acid. These reactions do not decrease the degree of polymerization of the polymers. Aromatic polymers with stiffening groups, such as PPO, polyarylsulfone, polyarylether ketone (PEEK), and polyphenylene sulfide (PPS), are more resistant to attack by corrosives than those with flexibilizing groups. 

Films of the polyisoimides were cast from DMAC at 55 °C under reduced pressure (0.1 mm). A study of the isomerization reaction was conducted by FTIR and showed that the isomerization began at approximately 100 °C and was complete after 3 h at 250 °C. In all cases the thermally treated films were insoluble in all solvents tested. Composite films were produced with XVII and three commercial matrix systems a polyarylsulfone (Radel), a polysulfone (Udel), and an acetylene terminated isoimide thermosetting resin (IP-600). Films of the matrix and XVII were cast from DMAC. Slightly cloudy films, indicating some phase separation, resulted with both the Radel and Udel systems. Composite films cast with IP-600, however, were completely clear and showed no signs of phase separation. The structural similarity of the IP-600 resin and XVII may account for the greater homogeneity of the system. Property assessment of these films before and after thermal treatment is currently underway. 

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