Aromatic polysulfones

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. 

In the first stage in order to test the process of various types of polymer films were surface-fluorinated. From 1990 to 1994 it was shown that XeF2 could be used effectively for surface fluorination of a variety of plastics. Polyethylene film and plates,18 aromatic polysulfone,19 polyvinyltrimethylsilane,20 and polycarbonate,21 among other polymeric materials, were fluorinated successfully. 

An aromatic polysulfone based on 4,4 -biphenol and 4,4 -dichlorodiphenyl sulfone (Bp PSF) was shown to be the most resistant of a systggatic series of poly (arylene ether sulfones) to Co gamma irradiation. 

Thus, the progressive accumulation of alkyl and/or arylsulfonyl groups onto a benzene ring (in the aromatic polysulfones (27)-(31)) led to an increasing stabilization of the corresponding anion radicals. 

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. 

Irradiation. Samples of the polymers were weighed into small glass ampoules and evacuated at ca. 100 Pa for at least 48 h before sealing. During evacuation the samples of poly (amino acid)s and aromatic polysulfones were heated to assist in removal of occluded moisture. 

Figure 12. Variation of the yield of radicals determined by ESR with radiation dose for bisphenol-A aromatic polysulfone showing (D) dose saturation and ( ) effect of photobleaching.

The presence of aromatic groups in polymers greatly reduces their radiation sensitivity. Aromatic polysulfones are commercially important engineering plastics with high temperature resistance and also show good radiation resistance (16). Development of polymers with improved radiation resistance should be possible by copolymerization of other aromatic structures into the chain. 

The GPC technique was used to determine gel formation. Figure 13 shows the soluble fraction of aromatic polysulfone I measured with this technique after irradiation at 30 and 150°C. The relative radiation resistance of different polymers can be obtained by comparison of the gel doses (the highest dose for complete solubility of the polymer) provided that the initial molar masses of the of the polymers are known, or from G(S) and G (X) values these can be derived from the dose dependence of the soluble fractions beyond the gel dose, using a Charlesby-Pinner, or Saito-type plot with allowance for the molar mass distribution. 

Figure 13. Dependence of the soluble fraction of bisphenol-A aromatic polysulfone on irradiation dose for irradiation at ( 3) 30° C, (O) 150°C, determined by GPC using miniature sample technique.

Figure 14. Variation of radical yield with copolymer composition for bisphenol-A — hydroquinone aromatic polysulfone copolymers after ...

The preliminary electron beam experiments on all aromatic polyfarylene ether sulfone)s were performed by Hedrick et al. [58] and the detailed investigation on radiation effects of these polymers were recently carried out by Lewis et al. [59]. They found that an aromatic polysulfone based on 4,4 -biphenol and 4,4 -dichlorodiphenyl sulfone exhibited the highest radiation tolerant in a systematic series of polyfarylene ether sulfone)s with "/-irradiation up to 4 x 106 Gy. 

Aromatic polysulfones are a commercially important class of thermoplastic polymers [127]. They have highly desirable qualities such as chemical inertness, thermal stability, and flame retardency [128,129]. Although a number of methods are available for the synthesis of polysulfones [130,131,132], step polymerization methods are the most widely used industrially [127]. Polysulfones have been synthesized with the involvement of sulfonylium cations as propagating species. 

P. Zschocke and D. Quellmatz, Novel ion exchange membranes based on aromatic polysulfone, J. Membr. Sci., 1985, 22, 325 W.H. Daly, Modification of condensation polymers, J. Macromol. Sci., Chem., 1985, A22, 713-728 N. Sivashinsky and G.B. Tanny, Ionic heterogeneities in sulfonated polysulfone films, J. Appl. Polym. Sci., 1983, 28, 3235-3245 M.D. Guiver, G.P. Robertson, M. Yashikawa and C.M. Tam, Funtionalized polysulfone Methods for chemical modification and membrane applications, Membrane Formation and Modification, ACS Symposium Series, ed. I. Pinnau and B.D. Freeman, American Chemical Society, Washington DC, 2000, Vol. 744. 

Main-chain aromatic polysulfonates are disclosed in numerous patents. As in the case of the polyamides, they are mostly prepared by a two-phase polycondensation using an aromatic disulfonyl chloride in a chlorocarbon solvent on the one hand, and an alkaline water solution of a diphenol on the other. The most commonly used diphenol is the industrially available Bisphenol A, in conjunction with aromatic disulfonyl chlorides. Typical cases are reported by Thomson and Ehlers82, e.g. 

Polysulfones are a family of engineering thermoplastics with excellent high-temperature properties. The simplest aromatic polysulfone, poly(p-phenylene sulfone)... 

The branching factor g, determined according to the Eq. (105), was used for pol5mier branching degree quantitative evaluation. For copolymers B-PES the aromatic polysulfone, not containing side substituents, was accepted as their linear analog [169]. 

NYLON (INCLUIMNG AROMATICS) POLVIMIDES POLYAMIOE-IMIOES THERMOPLASTIC POLYESTERS (INCLUDING AROMATICS) POLYSULFONES POLYSTYRENE / COPOLYMERS (EXCEPT ABS)... 

The evolution and expansion of the nse of ultrafiltration (UF) on an industrial scale became possible after the development of asymmetric polymeric membranes, especially of cellulose acetate and aromatic polysulfones (PSs). These membranes were initially developed for desalination of seawater by reverse osmosis and then were used in various applications from other polymeric materials. Until the development of asymmetric membranes, considered as second generation. 

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 ... 

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