Hyperbranched poly(ether sulfone)s: preparation and application to ion-exchange membranes

Abstract

Hyperbranched polymers possess unique characteristics such as low viscosity, high solubility in organic solvents and a high degree of functionality at the terminal position. However, hyperbranched polymers also possess weak mechanical properties. In this study, hyperbranched poly(ether sulfone)s (HBPES) possessing sulfonic acid moieties at the terminal position were prepared by reacting electrophilic sulfonium ions with electron-rich benzene rings from two kinds of AB 2 monomers. To address the weakness of HBPES, hybrid materials containing linear and hyperbranched PES were investigated. Linear and hyperbranched multiblock copolymers were successfully prepared by reacting oligomeric linear PES and AB 2 monomers. From the multiblock copolymers, linear and hyperbranched PES blends were prepared and applied as ion-exchange membranes for fuel cells. Films containing various ratios of linear and hyperbranched PES terminated by sulfonyl chloride groups were prepared via casting from a solution of DMAc. The results indicated that tethers between linear and hyperbranched polymers were important for controlling the size of the phases and for preventing the dissolution of HBPES in water; thus, linear and hyperbranched polymers were crosslinked by simply heating blends of both films. Finally, hybrid films containing sulfonic acid groups were obtained by hydrolyzing the sulfonyl chloride moieties. The resultant films showed ion-exchange capacities that were comparable to that of a Nafion 117 membrane (Dupont, Tokyo, Japan).

Development of an EOS based on lattice cluster theory for pure components

“…Their application includes, amongst other, the fields of medicine [1][2][3][4][5][6][7][8], catalysis [9][10][11][12][13], membrane materials [14][15][16][17][18][19][20], chromatography [21], tissue engineering [22] and chemical engineering [23][24][25][26], for soil irrigation [27], sensors [28][29][30][31], contact lenses [32][33][34][35] and thermosets [36][37][38], and as rheological modifiers [39,40], super absorber [41,42], and sun screens [43]. The importance of the subject can be assessed by looking at the yearly production of plastics alone of approximately 200 million tons [44].…”

Synthesis and properties of long-chain branched poly(ether sulfone)s by self-polycondensation of AB2 type macromonomers

“…Moore and coworkers reported that the film‐forming ability improved in the range 80–100% of AB monomers for hyperbranched polyimide copolymers . Kakimoto also reported poly(ether sulfone) (PES) copolymers synthesized from AB and AB 2 monomers via a two‐step, single‐pot approach . Although the resulting copolymers showed high molecular weight and a single glass transition, the films of the copolymers were too brittle to investigate the mechanical and physical properties.…”

Benzothiazole Sulfinate: A Sulfinic Acid Transfer Reagent under Oxidation-Free Conditions

“…They can be converted to sulfones, 1–5 sulfonamides, 5–7 and sulfonyl fluorides, 3,8 which are found in natural products, 9 pharmaceuticals, 10–13 and materials 14,15 and used for bioconjugation. 16,17 Classically, sulfinic acids are synthesized via oxidation of thiols using H 2 O 2 or by the reduction of sulfonyl chlorides (Scheme 1A).…”