DTA investigations of n-octadecanol films on complex carbon-silica adsorbents as a method for determination of their surface properties

Summary The properties of n-octadecanol films on complex carbonsilica adsorbents were investigated. It was found that two forms of oriented surface film exist on Carbosil surface. The structure of each form of the film distinctly depends on the nature of the surface patches of Carbosil. It was shown, using differential thermal analysis that it is possible to determine the ratio of carbonized and hydroxylated parts of the Carbosil surface.     

Studies on the thermal stability of the perfluorinated cation-exchange membrane Nafion-417

The thermal stability of the perfluorinated cationexchange membrane Nafion-417 was determined by means of simultaneous TG-DTA. The individual decomposition stages were studied via IR spectroscopy and ion-exchange capacity determinations. Nafion-417 is thermally stable up to 280 C. Above this temperature, sulfonic groups present in the membrane are split off (T _max = 345 C. In the temperature range 420–590 C, oxidative destruction of the perfluorinated matrix occurs, which is accompanied by practically total weight loss.

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Zusammenfassung Die thermische Stabilität der perfluorierten Kationenaustauscher-Membran Nafion 417 wurde durch simultane TG-DTA untersucht. Die einzelnen Zwischenstufen der Zersetzung wurden durch IR-Spektroskopie und Messung der Ionenaustauschkapazität charakterisiert. Nafion 417 ist thermisch stabil bis 280 C. Oberhalb dieser Temperatur werden die vorhandenen Sulfonsäuregruppen abgespalten (Maximum bei 345 C). Im Temperaturbereich 420–590 C findet oxidativer Abbau, verbunden mit völliger Gewichtsabnahme, statt.

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- -147 . . , -147 280. ( .=345) , 420–590 - , .