Sulfonation of poly

Kobayashi et al. reported sulfonation of poly(4-phenoxybenzoyl-1,4-phenylene) (PPBP) with sulfuric acid and compared the data with those of sulfonated PEEK. As reported, the authors employed sulfuric acid for the sulfonation reaction to avoid or at least minimize degradation of the polymer by chlorosulfonic acid or fuming sulfuric acid (Figure 27). 

Title Isolatable, Water-Soluble, and Hydrolytically Stable Active Sulfones of Poly(Ethylene Glycol) and Related Polymers for Modification of Surfaces and Molecules... 

It was later shown that other types of polyelectrolytes involving partial sulfonation of poly(vinylnai ithalene) [5,6] and copolymers of aromatic monomers with styrene sulfonate would also lead to polymers which in aqueous solution achieved this hypercoiled configuration. 

The surface sulfonation of poly(styrene-divinylbenzene) beads with cross-linking ranging from 0.5 to 8 % divinylbenzene was studied by Small [27,28]. Examination of the sulfonation depth of a resin bead in terms of optimum separation of several inorganic cations was subsequently studied by Stevens and Small [29]. Ihese resins were used for the chromatographic separation of simple cations. 

G.N. Richard, Ion-exchange membranes by sulfonation of poly(vinylidene fluoride) films. J. Appl. Polym. Sci., 1964, 8, 2269-228. 

Y. Gao, G. P. Robertson, M. D. Guiver, X. Jian, S. D. Mikhailenko, K. Wang, and S. Kaliaguine. Sulfonation of poly(phthalazinones) with fuming sulfuric acid mixtures for proton exchange membrane materials. J. Membr. ScL, 227(l-2) 39-50, December 2003. 

Novel polymer electrolytes exhibiting high proton conductivity (higher than 10 Scm ) were prepared by sulfonation of poly(ether sulfone) (PES) (97,98). In these polymers the protons of the sulfonic acid groups are partially replaced by metal ions (Mg, Ti, Al, Ln) which leads to extension of the durabihty of the electrolytes. 

The presence of the nonpolar and polar moieties has led to phase segregation, which is desirable for transport properties. The higher phase segregation in Naflon has created broader water channels with fewer dead ends and thus more interconnected channels. With the presence of water, this microstructure transports water and proton better, which confers on Naflon a high proton conductivity when fully hydrated. However, this microstructure is a drawback for the methanol crossover, which is also very high, to a greater amount than that of sulfonation of poly(ether ether ketone) (SPEEK). 

The sulfonation of poly(ether ether ketone) is similar to the sulfonation technique for PSSA using sulfonation agents such as high concentration of sulfuric acid. The DS of SPEEK can be controlled by varying the reaction time and temperature (Xing et al. 2004). The work of Lee et al. showed that the proton conductivity of the SPEEK membrane increased with DS (Lee et al. 2007). The increase in DS will increase the hydrophilicity and water uptake and, consequently, gives an opportunity for the formation of water-mediated pathways for protons. Methanol permeability measurement indicates that its rate increases with the increase of DS but at a much lower rate than the Naflon membrane. This is due to the difference in their microstructures (Li et al. 2003a). 

X. Feng, Sulfonation of poly(ether ether ketone) (PEEK) kinetic study and characterization, J. Appl. Polym. Sci. 82 (11) (2001) 2651-2660. 

M.H. Jeong, K.S. Lee, Y.T. Hong, J.S. Lee, Selective and quantitative sulfonation of poly(arylene ether ketone)s containing pendant phenyl rings by chlorosulfonic acid, J. Memb. Sci. 314 (1-2) (2008) 212-220. 

Poly(arylene ether)s are one of the most studied aromatic polymers for the sulfonation reactions. Poly(arylene ether)s include poly(phenylene ether), poly(arylene ether ketone), poly(arylene ether ether ketone), and poly(arylene ether sul-fone). These polymers contain electron-rich phenylene rings linked by ether bonds, which are susceptible for the sulfonation reactions with typical sulfonating reagents such as sulfuric acid, chlorosulfonic acid, or sulfur trioxide. The first attempt was the sulfonation of poly(2,6-dimethyl-phenylene ether) (PPO) by General Electric in 1960s [4]. Since then, a number of... 

Sundhohn and co-workers [128-131] reported the preparation of PCMs by direct sulfonation of poly(vinylfluoride) (PVF) by means of irradiation with heavily charged particles (protons or electrons) prior to sulfonation. The obtained membranes (PVF-g-SA) displayed ionic conductivities up to 20 mS cm". The state of water [132] and the structure [133] of these membranes were established. The water swelling properties of such membranes was lower than Nafion 117 and 112. Interestingly, PEMFC tests with these membranes showed better performance than Nafion 117 membranes, unlike Nafion 112, which performed better than PVF-g-S A membranes [134]. However, these membranes failed after 200 h of testing due to membrane rupture between the membrane active area and the gasket. 

M. Paronen, F. Sundholm, E. Rauhala, T. Lehtinen and S. Hietala, Effects of irradiation on sulfonation of poly(vinyl fluoride), J. Mater. Chem. 7, 2401 (1997). 

Another example is the sulfonation of poly(ether sulfone)s via Uthium organic intermediates, which creates special sites for sulfonation [4,5]. Although this latter technique was developed for a different reason, it offers the possibility to create sites that are active for sulfonation but not for crossUnking (Fig. 4). 

Unveien, E.E., Erdogan, T., Qelebi, S.S., Inan, T.Y., Role of post-sulfonation of poly(ether ether sulfone) in proton conductivity and chemical stability of its proton exchange membranes for fuel cell, Int. J. Hydrogen Energy, 2010, 35, 3736-3744. 

FIGURE 7.10 Sulfonation of poly(aminophosphazenes) with 1,3-propanesultone. (Reprinted with permission from Allcock, H.R., Klingenberg, E.H., and Welker, M.F., Alkanesulfonation of cyclic and high polymeric phosphazenes. Macromolecules, 26, 5512. Copyright 1993 American Chemical Society.)... 

FIGURE 7.12 Sulfonation of poly[iw(3-methylphenoxy)phosphazene]. (Tang, H., Pintauro, P.N., Guo, Q., and O Connor, S. Polyphosphazene memhranes. III. Solid-state characterization and properties of sulfonated poly[hw(3-methylphenoxy)phosphazene]. J. Appl. Polym. Sci. 1999. 71. 387-399. Copyright Wiley-VCH Verlag GmhH Co. KGaA. Reprinted with permission.)... 

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