Udel® Polysulfone Poly

Udel Polysulfone Poly(bisphenol A sulfone) Solvay... 

Two types of polysulfone are eommonly used in the manufacture of membranes Vitrex poly-(ether sulfone) and Udel polysulfone. Their molecular structures are showed in Scheme 2. 

The nucleophilic substitution reaction of an activated benzenoid halide with a phenoxide anion is currently the method used worldwide for the preparation of aromatic poly(aryl ether sulfones) " and poly(aryl ether ketones). " Amoco Performance Products UDEL Polysulfone and RADEL Polyphenylsulfone are made commercially via this route. The subject substitution reactions are also used by ICI to produce their Victrex Poly(ether sulfone) (PES) and Victrex Poly(ether ether ketone) (PEEK). 

Several polyaiylene ethers such as UDEL (polysulfone, Tg 190 C), RADEL (poly-phenylsulfone, Tg 220 C), Kadel-H (polyketone, Tg 160 C, 340 C), ... 

In the fall of 1966, researchers at North Star Research Institute began a search for compression-resistant microporous substrates.19 This effort resulted in the development of microporous sheets of polycarbonate (Lexan) and poly-sulfone (Udel).20 Figure 5.4 shows a graph comparing the flux levels and flux stability for three membranes made at that time (a) float-cast cellulose acetate on microporous polysulfone, (b) float-cast cellulose acetate on a mixed cellulose ester microfilter support and (c) a standard asymmetric cellulose acetate membrane. The improvement in membrane fluxes was readily apparent, when switching from cellulosic substrates to the microporous polysulfone substrate. 

Fig. 6.9 Structure of (a) sulfonated Udel-1700 polysulfone, and (b) sulfonated poly(arylene ether sulfone) (sPAES)...

Sulfonated polysulfones (sPSf) can be prepared by sulfonation of commercial polysulfones, such as Udel 1700 (Solvay), or poly(arylene ether sulfones) (PAES), leading to structures like that shown in Fig. 6.9a [7, 186]. Also, they can be synthesized by direct copolymerization of sulfonated monomers available commercially [7, 187, 188], to produce polymers with the structure shown in Fig 6.9b. 

Other polysulfone membranes for DMFC were prepared by sulfonation of commercial polyethersulfone with Cardo group (sPES-C) [473] (Fig. 6.9), by sulfonation of a commercial poysulfone and the use of silica as a filler [474], by "click" cycloaddition of alkyne sulphonate to polysulfone containing azide moieties and crosslinked with 1,7-octadiyne [475], and by polycondensation of 4,4 -difluorodiphenyl sulfone (DFDPS) and l,3-bis(4-fluorobenzoyl)benzene,6,7-dihydroxy-2-naphtha lene sulfonate with bisphenol [476]. Commercial poly(phtalazinone ether sulfone ketone (PPESK) [477], Udel (Solvay) polysulfone [478-480], and Lasuf Lati SPA) polysulfone [481] were sulfonated to prepare membranes for DMFC. Relative selectivity larger than 7 have been obtained with some of these membranes [477,478], as indicated in Fig. 6.37. 

Table 4 shows the relative atomic concentrations of the dominant elements on the surface of both polysulfone membranes, although other elements (impurities) such as calcium in D-PS or sodium and chlorine in P-PS were also observed in relative concentrations lower than 0.5 %. According to the theoretical molecular structure of poly-(ether sulfone) (Vitrex) the 0/C and S/0 atomic ratios are 0.25 and 0.33, respectively while for polysulfone (Udel) the 0/C ratio is 0.15 and the S/0 ratio is 0.25. As can be observed from the 0/C ratio indicated in Table 4, both polysulfone membranes show an excess of oxygen with respect to sulfur atoms, and an excess of carbon with respect to oxygen atoms, which points out the presence of atypical chemical compounds containing also carbon and oxygen atoms. 

As already mentioned, the acid-base blend concept was applied to intermediate-T fuel cell membranes by Hasiotis et al. [31, 42]. The blend membranes were composed of PBI Celazol (poly(2,2 -/M-phenylene-5,5 -bibenzimidazole, m-PBl, named as Bl) and polysulfone Udel sulfonated in the bisphenol A section (named... 

The electrochemical properties of cation-exchange membranes based on sulfonated poly(arylene ether sulfone)s (s-PES) were described in a paper by Kang et al. [100]. The intended applications for these membranes were general electro-membrane rather than fuel cell applications. The properties of the membranes prepared in this work were compared to commercially available ion-exchange membranes (Neosepta CM-1, CMX, and CMB), as well as to sulfonated polysulfones obtained by post-sulfonation of Udel 1700 with chlorosulfonic acid (s-PSU) (Fig. 26). The s-PES membrane materials were... 

Polysulfone, PSF, Udel P1700 was obtained from Union Carbide. The ethylene-propylene copolymers from Japan Synthetic Rubber Co. were provided by Dr S. Machi of the Japan Atomic Energy Research Institute. Poly(methacrylic acid) was prepared by polymerization of methacrylic acid in aqueous HCl with persulfate initiator and purified by dialysis and freeze drying. 

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