Cross-Linking Disulfonated Poly(arylene ether sulfone) Telechelic Oligomers. 1. Synthesis, Characterization, and Membrane Preparation

Abstract

meta-Aminophenol was used during nucleophilic step copolymerization to end-cap partially disulfonated bisphenol A based random copolymers with controlled oligomeric molecular weights. The amine end groups were thermally reacted with a tetrafunctional epoxy reagent to produce networks. Very high gel fractions, up to 99%, and ductile film formation were achieved. The oligomer was further functionalized with acryloyl chloride, phenylethynyl phthalic anhydride, and maleic anhydride to obtain several novel free radically cross-linkable oligomers. The structure and molecular weights (M n) were established with 1H NMR spectroscopy of the oligomers and end groups. TGA analysis demonstrated the high thermal stability of these oligomers; DSC investigations showed that the oligomers had curing exotherms from 140 to 330 °C and that residual casting solvent during cross-linking was necessary to avoid vitrification during membrane formation. In addition to the thermally cross-linkable systems, photocross-linking was demonstrated with the telechelic acrylamide functionalized oligomers. Two compositions were identified as potential candidates for further development. Cross-linking disulfonated poly(arylene ether sulfone) copolymers limits the high water sorption and swelling of these hydrophilic materials, which enhances several properties for membrane applications. Initial transport results indicate that cross-linking greatly reduces salt permeability while modestly decreasing water permeability, resulting in improved water/NaCl selectivity.

Cross-Linked Disulfonated Poly(arylene ether sulfone) Telechelic Oligomers. 2. Elevated Transport Performance with Increasing Hydrophilicity

“…The epoxy-cross-linked amBPS and amBisAS networks were prepared as relatively large (10 cm × 15 cm) membranes according to a previously established procedure. 9 All six of the cross-linked copolymers had gel fractions greater than 89.5%. With regard to water purification properties such as water and salt permeability, the cross-link density and molecular weight between cross-links (M c ) are of interest.…”

“…Part 1 of this study described numerous examples of crosslinking disulfonated polysulfones and introduced several new reactions for cross-linking telechelic sulfonated polysulfone oligomers. 9 One successful cross-linking route produced ductile films with gel fractions up to 99%, among the highest reported to date for such disulfonated polysulfone copolymers. The reaction between amine terminated oligomers and an approximately tetrafunctional epoxy resin was identified as a suitable candidate for further investigation regarding the effects of cross-linking on water purification properties.…”

Synthesis and photocrosslinking of disulfonated poly(arylene ether sulfone) copolymers for potential reverse osmosis membrane materials

“…Direct copolymerization of partially disulfonated poly(arylene ether sulfones) ( Figure 1) synthesized via nucleophilic aromatic substitution step polymerizations have been previously described by McGrath et al 13,17,23,[26][27][28][29] The 3,3'-disulfonated-4,4'-dichlorodiphenylsulfone (SDCDPS) monomer was used to control the degree of sulfonation and therefore the hydrophilicity of the copolymers. 13,14 Oligomers with targeted molecular weights of ~5,000 g/mol were investigated in this research utilizing a monofunctional endcapping reagent to limit the molecular weights.…”

“…22 Our group has reported the synthesis of telechelic disulfonated oligomers with phenol and aromatic amine functionalities crosslinked with epoxy reagents previously. 17,23 Herein we report the synthesis of acrylamide-terminated disulfonated poly(arylene ether sulfone) oligomers and crosslinking of the new materials with multifunctional acrylate co-monomers using UV light.…”

Soluble Telechelic Polycondensation Poly(ether ketones): Synthesis and Characterization

“…They are nevertheless important industrial polymers, with unique properties, and are often used to prepare membranes for fuel cells and for separation technologies . Synthesis of PEK and PES prepolymers is therefore relatively frequent in the literature, based on protection–deprotection reactions or polycondensation, recent work in this field including that of Sundell et al for membrane applications in water purification or in gas separation, whereas sulfonate‐containing poly(aromatic ethers) have been proposed for fuel cells …”