Polysulfones commercial products

Use of nanofiltration for non-aqueous separations is limited by membrane compatibility - a common material in composite nanofiltration membranes used for aqueous separations is polysulfone which possesses limited solvent resistance [134]. However, during the past two decades a number of materials have emerged with improved solvent resistance that have enabled a broad range of organic solvent nanofiltration (OSN) applications. These materials include polydimethylsiloxane, polyphenylene oxide, polyacrylic acid, polyimides, polyurethanes, and a limited number of ceramics. Commercial products are offered by Koch Membrane Systems, W.R. Grace, SolSep, and Hermsdorfer Institut fur Technische Keramik (HITK) [135]. 

Polysulfone. Polysulfone is a commercial polymer that is a product of bisphenol A and 1,1 -sulfonylbis (4-chlorobenzene) (see Polymers... 

Proprietary blend formulations based on polysulfone, polyethersulfone, and polyphenylsulfone are sold commercially by Amoco Corporation to meet various end use requirements. The blends based on polysulfone are sold under the MINDEL trademark. A glass fiber-reinforced blend based on PES is offered under the trade name RADEL AG-360. This offers most of the performance characteristics of 30% glass fiber-reinforced polyethersulfone but at a lower cost. Two blend product lines are offered based on PPSF. These are designated as the RADEL R-4000 and R-7000 series of products. The former is a lower cost alternative to RADEL R PPSF homopolymer offering most of the performance attributes unique to PPSF. The R-7000 series of resins have been formulated for use in aircraft interiors for civil air transport. They exhibit a very high degree of resistance to flammabihty and smoke release. 

There are three commercial suppHers that manufacture polysulfones Amoco Corporation ia the United States, BASF Corporation ia Germany, and Sumitomo Chemical Company ia Japan. A listing of the resias suppHed by each of these companies along with the trade names particular to each of these suppHers is shown ia Table 9. AH three companies supply a polyethersulfone-type product. Polysulfone, on the other hand, is suppHed by Amoco and BASF, and Amoco is the sole suppHer of polyphenylsulfone. 

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. 

Another group of potentially large volume plastics that is under development are the polysulfone resins, made by the copolymerization of olefins such as 1-butene with sulfur dioxide 24). Both these feed stocks could be derived in abundant quantities and at relatively low costs from petroleum sources. The polysulfone resins are moldable thermoplastic polymers having physical properties that vary widely depending on the olefin from which they are prepared. They are considered to have excellent prospects for development to a large volume, low cost commercial plastic and may permit the entrance of plastic products into other fields in which they are now limited by the high cost and inadequate supply of present thermoplastic materials. 

In addition to sulfone, phenyl units, and ether moieties, the main backbone of polysulfones can contain a number of other connecting units. The most notable such connecting group is the isopropylidene linkage which is part of the repeat unit of the well-known bisphenol A-based polysulfone. It is difficult to clearly describe the chemical makeup of polysulfones without reference to the chemistry used to synthesize them. There are several routes for the synthesis of polysulfones, but the one which has proved to be most practical and versatile over the years is by aromatic nucleophilic substitution. This polycondensation route is based on reaction of essentially equimolar quantities of 4,4,-dihalodiphenylsulfone (usually dichlorodiphenylsulfone (DCDPS)) with a bisphenol in the presence of base thereby forming the aromatic ether bonds and eliminating an alkali salt as a by-product. This route is employed almost exclusively for the manufacture of polysulfones on a commercial scale. 

A detailed study of SPSF desalination membranes was carried out by Brousse and coworkers43. Sulfonation was effected by chlorosulfonic acid on a commercial material (Polysulfone P 1700, Union Carbide), and the products as well as their sodium salts were cast from highly polar solvents. Their performance was compared to that of noncharged cellulose-acetate membranes, largely being used for desalination of brackish water. 

The only olefin-sulfur dioxide product sold commercially is sulfolene by Phillips Petroleum Co. The linear polymers remain to be commercially produced. It is interesting to note that a polysulfone, i.e., poly(phenylene sulfone), has been sold commercially since 1966 [8]. 

Polyetherification processes form the basis of commercial polysulfone production methods. For example, the Udel-type polymer (Union Carbide) is prepared by reacting, 4,4 -dichlorodiphenylsulfone with an alkali salt of bisphenol A. The polycondensation is conducted in highly polar solvents, such as dimethylsulfoxide or sulfolane. 

Polysulfones are transparent (though often slightly yellow), have low flammability (limiting oxygen index typically 38), and bum with little smoke production. Typical properties of some of the commercial polysulfones are shown in Table 4.31. 

The original preparation of aromatic polysulfones was described in 1958. This was followed by investigations of many different structures of polysulfones. One current commercial material is a condensation product of 2,2 -bis(hydroxyphenyl) propane with 4,4 -bis(chlorophenyl) sulfone. It fohns by a ) llliamson synthesis, because the reactivity of the halogens is enhanced by the sulfone groups ... 

Low-temperature process Production of relatively pure CO2 stream Both chemical and physical absorption are mature technologies Commercial polymeric membranes are available (polyimide, polysulfone, polyether-polyamide copolymer, etc.) and can be used with an adsorption liquid (e.g. MEA)... 

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