Highly Sulfonated Poly(phenylene sulfone): Preparation and Stability Issues

Abstract

This paper presents a preparation route which allows the formation of a poly(phenylene) ionomer containing merely sulfone units (-SO 2 -) connecting the phenyl rings and in which each phenyl ring is monosulfonated (100% degree of sulfonation). This corresponds to an ion exchange capacity (IEC) of 4.5 mequiv g -1 (equivalent weight of EW ) 220 g equiv -1 ). The preparation succeeded in a two-step process comprising a polycondensation reaction of sulfonated difluorodiphenyl sulfone with sodium sulfide, yielding sulfonated poly(phenylene sulfide sulfone), and the subsequent oxidation to the corresponding sulfonated poly(phenylene sulfone). The polymer was characterized by elemental analysis, NMR, IR, GPC, viscosity measurement, TGA in air and in pure water vapor atmosphere, DSC at low and high temperatures, and ac impedance spectroscopy. Room temperature water absorption isotherms have been determined by equilibrating samples at different relative humidities. Under the chosen reaction conditions, polymers with molecular weights up to M w ≈ 61 000 g mol -1 were obtained, corresponding to intrinsic viscosities up to 0.73 dL g -1 . The water-soluble ionomer exhibits a very high density (F ) 1.75 g cm -3 in the dry form), no glass transition or melting temperature, and a very high thermooxidative and hydrothermal stability. The latter is attributed to the specific molecular structure consisting of extremely electron-deficient aromatic rings. At high temperature (T ) 110-160 °C) and low relative humidities (rh ) 50-15%) the proton conductivity exceeds that of Nafion by a factor of 5-7.

Sulfonated hydrocarbon membranes for medium-temperature and low-humidity proton exchange membrane fuel cells (PEMFCs)

“…32(b)) and had an extremely high IEC (4.3-4.5 mequiv. g −1 ) [131]. In its dry state, the polymer also possessed a remarkably high density (1.75 g cm −3 ) that was nearly as high as the density of pure sulfuric acid (H 2 SO 4 ; 1.83 g cm −3 ).…”

“…A series of sulfonated poly(phenylene sulfone)s (SPPSfs) containing only sulfone units (-SO 2 -; electron-withdrawing group) connecting the phenyl rings was prepared via a two-step process consisting of a nucleophilic aromatic polycondensation reaction to prepare sulfonated poly(phenylene sulfide sulfone)s (SPPSSfs) and their subsequent oxidation to SPPSfs (see Fig. 32) [63,131,132]. These ionomers exhibited increased acidity and higher hydrolytic stability of the sulfonic acid groups due to the absence of electron-donating groups, such as ether linkages, in their backbone structure.…”

Surface adsorption of sulfonated poly(phenylene sulfone)/C14TAB mixtures and its correlation with foam film stability

“…Monosulfonated poly(phenylene sulfone) (sPSO 2 -220) was synthesized according to the guidelines in the literature. 21 It had a molecular mass of 100 000 g mol À1 with Li + as counterion. The flexible polyelectrolytes PAMPS and PSS, which were used for comparison, had a molecular mass of 100 000 g mol À1 and 70 000 g mol À1 , respectively.…”

“…Sulfonated poly(phenylene sulfones) are a novel class of polyelectrolytes, 20,21 which are of interest due to their high proton conductivity and their high thermal, thermo-oxidative and hydrolytic stabilities. 20,22 These properties make sPSO 2 -220 a promising material e.g.…”

Crystalline and thermal properties in miscible blends of PEEK, PPS and PEI obtained by melt compounding

“…PPS can also act as a flow aid for plastic alloys due to its excellent melting process characterization [6][7][8][9]. The polymer poly(etherimide) (PEI) and PEEK are a class of high performance engineering polymers that are high temperature resistant and known to be miscible in the amorphous phase [10][11].…”