Polysulfones dioxide

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. 

The free-radical reaction may be equally initiated by photoactivated sulfur dioxide (3S02)442 (equation 79). On the other hand, polysulfones are obtained by radical copolymerization of appropriate olefins with sulfur dioxide443-449, and similarly, uptake of sulfur dioxide by a radical-pair formed by nitrogen extrusion from an azo compound yields the corresponding sulfone450 (equation 80). Correspondingly, alkylbenzenes, dibenzoyl peroxide, and sulfur dioxide yield sulfones under thermal conditions451... 

Sulfur dioxide was the major volatile product and was used as a probe to correlate the radiation resistance with polymer structure. The use of biphenol in the polymer reduced G(SO ) by 60% compared with bisphenol A based systems (Bis-A PSF). Surprisingly, the isopro-pylidene group was shown to be remarkably radiation resistant. The ultimate tensile strain decreased with dose for all polysulfones investigated and the rate of decrease correlated well with the order of radiation resistance determined from volatile product measurements. The fracture toughness (K ) of Bis-A PSF also decreased with irradiation dose, but the biphenol based system maintained its original ductility. 

Sulfur dioxide does not homopolymerize but does participate in a rather wide variety of free radical copolymerizations with unsaturated monomers. The resulting polysulfones have been known for quite a long time. Solonina ( f ) obtained a white solid from the reaction of SO2 with allyl ethers in 1898, but such products were not recognized as copolymers until the work of Marvel and Staudinger in the 1930 s. 

Polysulfone Cheiin DvncUtiics. Carbon-13 nmr has been used recently to resolve a puzzling problem in the dynamics of polysulfone chains (9,10,11). Some years ago. Bates, Ivin and Williams (12) reported that measurements of the dielectric dispersion in solutions of alternating 1 1 copolymers of sulfur dioxide with hexene-1 and 2-methylpentene-1 show no loss in the high frequency region, Le. 

Frederick Frey and Walter Shultze were instrumental early researchers. Frey was among the first to dehydrogenate paraffins catalytically to olefins and then the olefins to diolefins that serve as feedstocks to the production of many of today s polymers. In competition with Bakelite, he discovered the preparation of polysulfone polymers made from the reaction of sulfur dioxide and olefins creating a hard Bakelite-like material. Frey and Schultz also developed a process that allowed the production of 1,3-butadiene from butane that allowed the synthesis of SR. 

Ring-opening polymerization of 1,2-thiazetidines, because of their highly strained ring structure, is often investigated for eventual technological applications. Imai et al. have produced a new class of polyamide-polysulfon-amide, using this technique. 4,4-Dimethyl-l,2-thiazetidin-3-one 1,1-dioxide... 

Materials. Poly (olefin sulfone)s were prepared by copolymerization of liquid mixtures of sulfur dioxide and the appropriate olefin using tert.-butyl hydroperoxide as initiator in the temperature range from —80 to 0°C. The poly (amino acid)s were obtained from Sigma Chemical Co. and used without further purification. The poly (olefin) s were provided by Mr. O. Delatycki and Dr. T. N. Bowmer and were prepared under controlled conditions. The aromatic polysulfones were prepared and purified by Mr. J. Hedrick. The purity of all polymers was checked by H and 13C NMR. 

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. 

The kinetic technique was extensively used by Dainton and his associates (3, 4) particularly in their studies of the copolymerization of olefins with sulfur dioxide to 1 1 polysulfones. To check their results, they compared the heats of polymerization calculated from the ceiling... 

Japanese investigators reported that liquid sulfur dioxide polymerizes styrene derivatives (e.g., p-methyl styrene, a-methyl styrene) (19). Unfortunately, the experiments were not executed under rigorously anhydrous conditions (high vacuum) so that the possibility for proton (e.g., sulfurous or sulfuric acid) initiation exists although the authors seem to believe that S02 is the catalyst, probably by the following process 2S0a SO2 +SO e. The cationic nature of the mechanisms was proven by the facts that no polysulfones formed, that the polymerization was inhibited by bases, and that free radical inhibitors did not affect the reaction. These authors also claim that formaldehyde is polymerized by sulfur dioxide to a product which does not contain sulfur and whose infrared spectrum closely resembles that of a low temperature sample. 

The polysulfones from vinyl chloride and vinyl bromide also contain two moles of vinyl halide per mole of sulfur dioxide (59, 60), apparently as a result of a similar reaction. 

Sulfur dioxide reacts generally with transition metal alkyl, aryl, and a-allyl complexes to give sulfinate complexes. The reaction, first described in 1964 by Wojcicki and Bibler, resembles well-known insertion reactions of CO, C2F4, SnCl2, tetracyanoethy-lene, and other unsaturated species into metal-alkyl bonds, but there are important stereochemical and mechanistic differences Sulfur dioxide insertion into metal-alkene and metal-alkyne bonds have not been reported. However, PdCl2 has been used as a catalyst for copolymerization of ethylene and SO2 to polysulfones and insertion into a Pd-ethylene bond is a conceivable reaction step. 

Up to 1973 very little information had been published on these foams. France has produced polysulfone foams from expandable beads which resemble polystyrene beads in their processing. In a typical formulation 1- butene and sulfur dioxide are copolymerized in such a way that the copolymer contains excess unpolymerized 1-butene, which volatilizes to cause foaming. Water, ethyl hydroxyethyl cellulose, 1-butene, sulfur dioxide, and a solution of isoprophyl peroxydicaibonate in... 

Another industrial application of gas-separation membranes is the removal of carbon dioxide from natural gas. The CO2/CH4, selectivity is about 20 to 30 for polycarbonate, polysulfone, and cellulose acetate membranes at 35°C and 40 atm. A selectivity of over 60 can be obtained with Kapton , but this polymer is much less permeable than the others. Increasing the temperature raises the permeability of most polymers but generally causes a. slight decrease in selectivity. The operating temperature is chosen to be somewhat above the dew point of the residue gas. There is considerable COj absorbed in the membranes at high CO2 partial pressures, and the plasticization effect of CO2 increases the effective diffusion coefficients for all gases and makes the selectivity less than that based on pure-gas data. Methods of allowing for such nonlinear effects have been presented. ... 

Sulfur dioxide reacts with olefins in the presence of radical-forming catalysts to yield polysulfones,52 but cyclic sulfones can be obtained from butadiene, 2,3-dimethylbutadiene, isoprene, and hexadiene under specific conditions 53... 

Few argue that we have much to learn about the Thiokols and other polysulfide elastomers, the polysulfones, which have such interesting properties as the engineering plastics, and the episulfides. The chemistry of pyrites, carbon disulfide, sulfur dioxide, dimethyl sulfoxide, and many other compounds merit separate reviews. 

Marvel reported that propylene and cyclohexene react with sulfiir dioxide to form alternating copolymers of olefin and sulfiir dioxide in a head-to-tail arrangement [2,4], Staudinger reported that 1,3-butadiene reacts with sulfur dioxide to form a cyclic sulfone and an amorphouse linear polysulfone [3,3a, 5]. 

The olefin-sulfur dioxide polysulfone compositons are usually light-colored, thermoplastic, amorphous products that are moldable and extrudable. The polymers are not very resistant to alkaline solutions. 

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]. 

NMR analysis has indicated [9b] that the olefin used does not isomerize during copolymerization. Various vinyl monomers copolymerize with SO2 such as vinyl chloride, styrene, acrylamide, and chloroprene. However, methyl methacrylate is reported [9b] to homopolymerize in SO2 when used as a solvent (cationially or radically) but not to form polysulfones (sulfur dioxide copolymers). 

In 1910 Badische Aniline und Soda-Fabrik Aktien-Gesellschaft (BASF) [la] obtained a patent on the product (polysulfone) obtained by the action of sunlight on a solution of ethylene in sulfur dioxide in a sealed tube. The same patent... 

TABLE III Percentage Conversion of 2-Butene and Sulfur Dioxide to Polysulfone [29] ... 

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