Polysulfonates, aromatic

A combination of two identical CSTR s in series is to be used, to prepare a mixture of polysulfonated aromatic compounds. The reaction will occur isothermally in the liquid phase and may be represented as... 

Sinclair-Koppers Co. Lexan 125 bisphenol A polycarbonate from General Electric Co. Polysulfone aromatic poly(sulfone-ether) from Union Carbide Corp. and PPO poly(2,6-dimethyl-p-phenylene oxide) from General Electric Co. 

Membrane modules have found extensive commercial appHcation in areas where medium purity hydrogen is required, as in ammonia purge streams (191). The first polymer membrane system was developed by Du Pont in the early 1970s. The membranes are typically made of aromatic polyaramide, polyimide, polysulfone, and cellulose acetate supported as spiral-wound hoUow-ftber modules (see Hollow-FIBERMEMBRANEs). 

One class of aromatic polyethers consists of polymers with only aromatic rings and ether linkages ia the backbone poly(phenylene oxide)s are examples and are the principal emphasis of this article. A second type contains a wide variety of other functional groups ia the backbone, ia addition to the aromatic units and ether linkages. Many of these polymers are covered ia other articles, based on the other fiinctionahty (see Polymers containing sulfur, POLYSULFONES). 

The aromatic sulfone polymers are a group of high performance plastics, many of which have relatively closely related stmctures and similar properties (see Polymers containing sulfur, polysulfones). Chemically, all are polyethersulfones, ie, they have both aryl ether (ArOAr) and aryl sulfone (ArS02Ar) linkages in the polymer backbone. The simplest polyethersulfone (5) consists of aromatic rings linked alternately by ether and sulfone groups. 

The first aromatic sulfone polymer produced commercially was introduced as Bakelite polysulfone but now is sold by Union Carbide under the trade name Udel. It is made by reaction of the disodium salt of bisphenol A (BPA) with 4,4 -dichIorodiphenyl sulfone in a mixed solvent of chlorobenzene and dimethyl sulfoxide (eq. 12). 

A polysulfone is characterized by the presence of the sulfone group as part of its repeating unit. Polysulfones may be aUphatic or aromatic. AUphatic polysulfones (R and are alkyl groups) were synthesized by radical-induced copolymerization of olefins and sulfur dioxide and characterized many years ago. However, they never demonstrated significant practical utiUty due to their relatively unattractive physical properties, not withstanding the low cost of their raw materials (1,2). The polysulfones discussed in this article are those based on an aromatic backbone stmcture. The term polysulfones is used almost exclusively to denote aromatic polysulfones. 

As a variation on the base-catalyzed nucleopbilic displacement chemistry described, polysulfones and other polyarylethers have been prepared by cuprous chloride-catalyzed polycondensation of aromatic dihydroxy compounds with aromatic dibromo compounds. The advantage of this route is that it does not require that the aromatic dibromo compound be activated by an electron-withdrawing group such as the sulfone group. Details of this polymerization method, known as the Ullmaim synthesis, have been described (8). 

SolubiHty of the three commercial polysulfones foUows the order PSF > PES > PPSF. At room temperature, all three of these polysulfones as weU as the vast majority of other aromatic sulfone-based polymers can be readily dissolved in a few highly polar solvents to form stable solutions. These solvents include NMP, DMAc, pyridine, and aniline. 1,1,2-Trichloroethane and 1,1,2,2-tetrachloroethane are also suitable solvents but are less desirable because of their potentially harmful health effects. PSF is also readily soluble in a host of less polar solvents by virtue of its lower solubiHty parameter. 

Sulfonic acids may be hydrolytically cleaved, using high temperatures and pressures, to drive the reaction to completion. As would be expected, each sulfonic acid has its own unique hydrolytic desulfonation temperature. Lower alkane sulfonic acids possess excellent hydrolytic stability, as compared to aromatic sulfonic acids which ate readily hydrolyzed. Flydrolytic desulfonation finds use in the separation of isomers of xylene sulfonic acids and other substituted mono-, di-, and polysulfonic acids. 

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. 

Polysulfone can be used to I70°C (340°F) it is highly resistant to mineral acid, alkali, and salt solutions as well as to detergents, oils, and alcohols. It is attacked by such organic solvents as ketones, chlorinated hydrocarbons, and aromatic hydrocarbons. 

Used at temperatures up to 140°C, polysulfone has good resistance to aqueous solutions of acids and alkalis it is satisfactory with aliphatic solvents but is swollen by aromatics and stress cracked by several organic solvents, including acetone, ethyl acetate, trichlorethylene and carbon tetrachloride. 

Although the substitution of a preformed phthalocyanine always leads to a complex mixture of more- or less-substituted products, the reaction is of major industrial importance. Besides the chloro- and bromocopper phthalocyanines, also polysulfonated phthalocyanines, which are used as water-soluble dyes, are produced by the reaction of copper phthalocyanine with the respective reactant. While typical aromatic reactions of the Friedel-Crafts type are also possible,333 direct nitration of the macrocycle commonly results in oxidation of the phthalocyanine. However, under mild conditions it is possible to introduce the nitro group directly into several phthalocyanines.334... 

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. 

The nucleophilic aromatic substitution reaction for the synthesis of poly(arylene ether ketone)s is similar to that of polysulfone, involving aromatic dihalides and aromatic diphenolates. Since carbonyl is a weaker electron-withdrawing group titan sulfonyl, in most cases, difluorides need to be used to afford high-molecular-weight polymers. Typically potassium carbonate is used as a base to avoid the... 

Hexa-fluorobisphenol A (HFBPA) based polysulfone and poly(arylene ether phosphine oxide) were prepared by nucleophilic aromatic substitution similar to that of bisphenol-A-based polysulfone and poly(arylene ether phosphine oxide).11... 

Lyons and coworkers studied the ESR spectra of bakelite polysulfone [—CgH4— O—CgH4—SO2—CgH4—O—CgH4—C(CH3)2—] y-irradiated at 77 K and found features characteristic of at least four radicals, the cyclohexadienyl radical, formed from addition to the aromatic ring, methylene groups (— CH2) formed from H abstraction from the methyl group, phenoxy radicals and peroxy radicals. 

Oleum sulfonation of a styrene DVB co-polymer results in a polysulfonated polymer where more than one SO3H group might be present in the aromatic ring. Resin D, which is created via Path E/D is both polysulfonated and chlorinated resin. The results from the test study show that the same resin, with... 

Several studies have been performed on the photodecomposition of diaryl sulfones and polysulfones Khodair, et. al., (21) demonstrated that the photodecomposition of diaryl sulfones proceeds by a free-radical mechanism with initial carbon-sulfur bond cleavage. This gives an aryl radical and an aromatic sulfonyl radical. The latter radical can react with oxygen and a hydrogen donor to eventually form the hydroxyl radical. The hydroxy radical may attack the aromatic nucleus in PET and forms the hydroxyterephthaloyl radical. 

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