PHASE-DIAGRAM OF THE BINARY-SYSTEM OF BARIUM AND SODIUM N-BUTANOATES

The phase diagram of the binary system of barium and sodium n-butanoat es has been studied by differential thermal analysis, hot stage polari zation microscopy, and small angle X-ray diffraction. Pure barium n-bu tanoate exhibits a complicated thermal behavior: it melts at 519 It, t hen immediately solidifies, and remelts at a higher temperature (589 K ). The addition of a second component like sodium n-butanoate stabiliz es the liquid which appears with the first melting of barium n-butanoa te. This melt exists up to the temperature of the second melting, whic h may be called the clearing point because this liquid has been found to be slightly anisotropic and to have local bilayer smectic order. Th e temperature and concentration ranges of formation of the liquid crys talline smectic A solutions has been established. These liquid crystal line solutions are formed as a result of the eutectic reaction at 425 K. In this binary system, glass formation has been discovered in the c omposition range 0 to 70 mol % of Na n-butanoate.