Sulfonated polystyrene group

Resins containing these functional groups are generally available in one or more forms for example, strong acid cation resin is typically a sulfonated polystyrene type, available either in the hydrogen form (H+ ) or in the sodium form (Na+). The sodium form of this resin is used for water softening. 

Zyung et al., using ionomers such as sodium-sulfonated polystyrene as a CIM, have achieved an improved device performance [65,66]. Yang s group has used 0.2 wt% calcium acetylace-... 

In a study aimed at the identification of products of free radical reactions with polystyrene- and aromatic-based PEMs using model compounds, Hiibner and Roduner observed the addition of free radicals to the aromatic rings, preferentially in the ortho position to alkyl- and RO-substituents (in polystyrene- and aromatic-based PEMs, the para position is blocked by the presence of the sulfonic acid group). This study demonstrated the combined ortho-activation by these substituents and the meta-directing effect... 

Another concern for polystyrene- and some aromatic-based PEMs is hydrolysis of fhe sulfonic acid group from aromatic rings as well as hydrolytic cleavage of polymer backbone under fuel cell conditions for aromafic polymers including polyimides, poly(arylene ethers), poly(ether ketones), and poly(ether sulfones). It is well known that the sulfonation of aromafic rings is a reversible process especially at low pH and at elevated temperature (Scheme 3.3). The reversibility of sulfonation, for example, is used in fhe preparafion of trinitrotoluene or picric acid. Por the simplest membrane of the class of arylsulfonic acids (i.e., benzenesulfonic acid), fhe reacfion occurs upon freatment with a stream of superheated steam at 180°C.i ... 

Of all the hydrocarbon-based PEMs, this group most likely has the largest variety of different systems. This is probably due to the wealth of prior knowledge of the nonsulfonated analogues that have been developed over the last several decades as well as the general expectation of higher thermal stability, better mechanical properties, and increased oxidative stability over polystyrene-based systems. Within the context of this section, polyarylenes are systems in which an aryl or heteroaryl ring is part of the main chain of the polymer. This section will, therefore, include polymers such as sulfonated poly (ether ether ketone) and sulfonated poly(imides) but will not include systems such as sulfonated polystyrene, which will be covered in Section 3.3.I.3. 

Table I shows the molecular weight and the degree of end group substitution of the monofunctional polystyrene samples obtained. In Table II the corresponding data for the bifunctional samples are given. The samples were characterized by GPC in THF. and were calculated. Comparison with the corresponding nonfunctionalized control samples show good agreement. The results of the light scattering and osmotic pressure experiments with the acid form of the sulfonated polystyrenes were in agreement. No association was observed for THF solutions.

A similar marked tendency to form gels was observed for solutions of telechelic sulfonated polystyrenes in toluene. Again, it was not possible to dissolve the gel by dilution. In principle this could be achieved using a solvent in which the equilibrium of the association of the ionic groups is shifted towards the side of the unimers. Alternatively, the efficiency of the crosslinks can be diminished by addition of monofunctional material. The chains sulfonated only at one end would be incorporated into the micellar... 

The basis of the separation of amino acids by AAA lies in the interaction between acids - present in the elution buffer - and the stationary phase. This resin is made up of small sulfonated polystyrene particles. The negative charge of the sulfonic acid residues is counterbalanced by the Li+ -cations of the elution buffer. As the whole separation process takes place at a weakly acidic pH, the carboxylic acid residues are protonated and the interaction with the stationary phase of the column is achieved by the protonated (and thus positively charged) amino group(s) of the amino acids. The more basic the amino acid is, the stronger the interaction with the stationary phase and - consequently - the longer the retention time. So it is easily understood... 

The microenvironmental effect of various sulfonated polystyrene beads was studied using the Prins reaction as a probe.372 Reaction rates were found to be lower when carbomethoxy or carbobutoxy neighboring groups were present compared to phenyl. A less ionic microenvironment appears to allow for a higher concentration of styrene within the polymer and leads to an immediate reaction with protonated formaldehyde. 

Deuterium-decoupled deuterated amino adds bound to crosslinked polystyrene with sulfonic acid groups show line widths 3 to 4 times narrower than those from... 

Duolite C-20 is a polystyrene cation resin with sulfonic acid functional groups. It has a rated capacity of 0.8 equivalent per liter for cation exchange, except in the hydrogen cycle, for which its capacity is 1.5 equivalents per liter. Sulfonic acid groups are characterized as strong acid groups. 

Sulfinate and sulfone functional groups have been formed 355 by the reaction of sulfur dioxide with partially lithiated polystyrene. This reaction scheme follows ... 

Additional semipermeable membrane—forming polymers are selected from the group consisting of acetaldehyde dimethyl cellulose acetate, cellulose acetate ethyl carbamate, cellulose dimethylamino acetate, semipermeable polyamides, semipermeable polyurethanes, or semipermeable sulfonated polystyrenes. Semipermeable cross-linked selectively permeable polymers formed by coprecipitation of a polyanion and a polycation also can be used for this purpose.22 23 Other polymer materials such as lightly cross-linked polystyrene derivatives, semipermeable cross-linked poly(sodium styrene sulfonate), and semipermeable poly (vinylbenzyltrimethyl ammonium chloride) may be considered.24,25... 

Aldonic, uronic, and ascorbic acids, lactones, and N-acetylated amino sugars were separated on sulfonated polystyrene-divinylbenzene, a strong polyanion exchanger (Wheaton and Bauman, 1953). This method is adaptable to neutral carbohydrates without complexation or adsorption, by immersion in strong alkali to ionize the hydroxyl groups (ion chromatography). 

The sulfonated polystyrene beads can be used as a cation exchange resin. For example, if the sulfonated resin is treated with sodium hydroxide, the sodium salt of each of the sulfonic acid groups is formed. This resin can then be employed to exchange sodium cations for other cations in an aqueous solution. 

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