Sulfonate performance characteristics

This paper has provided the reader with an introduction to a class of polymers that show great potential as reverse osmosis membrane materials — poly(aryl ethers). Resistance to degradation and hydrolysis as well as resistance to stress Induced creep make membranes of these polymers particularly attractive. It has been demonstrated that through sulfonation the hydrophilic/hydrophobic, flux/separation, and structural stability characteristics of these membranes can be altered to suit the specific application. It has been Illustrated that the nature of the counter-ion of the sulfonation plays a role in determining performance characteristics. In the preliminary studies reported here, one particular poly(aryl ether) has been studied — the sulfonated derivative of Blsphenol A - polysulfone. This polymer was selected to serve as a model for the development of experimental techniques as well as to permit the investigation of variables... 

Development of Alternative Membranes. Nafion membranes show considerable promise with respect to their performance characteristics, low resistivity and long-term stability. However, the present cost (about 30/ft ) of Nafion membranes is rather expensive for the SPE cell to be cost-effective for industrial and utility applications. TJje ultimate goal is to reduce the membrane cost to about 3/ft. Alternative membranes have been evaluated for use in the SPE cell. Only fluorocarbon membranes have been considered in this application (10), since the cell environment is corrosive, and cell tempperature is high (from 80°C to 150°C). <, 3, 3 - trifluorostyrene-sulfonic acid... 

In a more recent approach, polyelectrolyte multilayers of poly(butanyl viologen) dibromide (PBV) and poly(styrene sulfonate) sodium salt (PSS) have been prepared (52) using an alternating polyion solution deposition technique. In this technique, the ITO substrate is alternatively exposed to positive and negative polyelectrolytes, with spontaneous polymer deposition via coulombic interactions between surface and polyion of opposite charge. In this layer-by-layer deposition technique, all redox material is electrochemically addressable, with good electrochromic performance characteristics. 

Sulfonated PBIs, other sulfonated polymers, and their blends show great potential for use as membranes in high-temperature fuel cells. The synthesis, conductivity, mechanical properties, and performance still require further development, but results so far are promising. Further investigation remains to determine whether these problems can be overcome and useful chemistries developed to meet the needs of high-temperature membranes with performance characteristics comparable to lower-temperature membranes. 

During the first trials with synthetic separators around 1940 it had already been observed that some of the desired battery characteristics were affected detrimentally. The cold crank performance decreased and there was a tendency towards increased sulfation and thus shorter battery life. In extended test series, these effects could be traced back to the complete lack of wooden lignin, which had leached from the wooden veneer and interacted with the crystallization process at the negative electrode. By a dedicated addition of lignin sulfonates — so called organic expanders -— to the negative mass, not only were these disadvantages removed, but an improvement in performance was even achieved. 

Calculating the Characteristic Interaction Parameter of the Micellar Systems Used To perform the calculation of p12 for the systems examined, i.e. Sulfonate/Genapol/ethoxylated nonylphenol mixtures, the following assumptions were made ... 

Some work [5] has been performed on the photochemical reaction between sulfur dioxide and hydrocarbons, both paraffins and olefins. In all cases, mists were found, and these mists settled out in the reaction vessels as oils with the characteristics of sulfuric acids. Because of the small amounts of materials formed, great problems arise in elucidating particular steps. When NO and 02 are added to this system, the situation is most complex. Bulfalini [3] sums up the status in this way The aerosol formed from mixtures of the lower hydrocarbons with NO and S02 is predominantly sulfuric acid, whereas the higher olefin hydrocarbons appear to produce carbonaceous aerosols also, possibly organic acids, sulfonic or sulfuric acids, nitrate-esters, etc. ... 

In light of the discussion above, it is desirable to alter the chemical nature of these polymers to induce a measure of hydrophilicity while maintaining the excellent physical character. Sulfonation has been known to dramatically alter a number of characteristics of poljmeric materials (for example, dyeabllity (17), tensile strength (18), and, of particular interest to the present studies, hydrophilicity (19)). In fact, sulfonation has been used to improve the reverse osmosis performance of poly(phenylene oxide)... 

The synthetic detergents industry originated in the 1940s, when it was found that a new anionic surfactant type—alkylbenzene sulfonate—had detergent characteristics superior to those of natural soaps. The first surfactant of this kind was sodium dodecylbenzene sulfonate (SDBS). This material was produced by the Friedel-Crafts alkylation reaction of benzene with propylene tetramer (a mixture of Co olefin isomers), followed by sulfonation with oleum or sulfur trioxide and then neutralization, usually with sodium hydroxide. The alkylation was typically performed using homogenous acid catalysts, such as HF or sulfuric acid. 

For example, at 50 composition, the CE Is 86 (vs 87 theoretically) for the former and 91 (vs 90 theoretically) for the latter blend (J6). Physically the unusual change in the curvature of the CE curves arises from differences In the transport characteristics and roles of the sulfonate and sulfonamide phases. In a sulfonate/carboxylate blend, the carboxylate phase is the selective component but the sulfonate phase is the conductive component. The lamellar morphology works because it forces the OH ions through the selective carboxylate domain which would otherwise be bypassed. In a sulfonamide/carboxylate blend, however, the carboxylate phase is both the selective and the conductive component. The lamellar morphology consequently hurts the performance by diverting the 0H ions across the sulfonamide phase unnecessarily. 

---