対称型2-オイレン酸, 1-, 3-飽和酸トリグリセライド : POP, SOS, AOA, BOBの混合系の結晶多形現象

The polymorphic behaviors of mixtures of some symmetric 2-oleic, 1-, 3-saturated acids triglycerides have been examined by X-ray diffraction method. The triglycerides examined are POP, SOS, AOA and BOB, in which the saturated acid moieties are palmitic, stearic, arachidic and behenic acids, respectively. The polymorphic modifications which were commonly detected as independent phases in all the above triglycerides are (tentatively named) α, β', sub β, X and β. The thermodynamical stability increases from α to β, leading a monotropic transformation along the direction from α to β described above. The mixtures were blended using a basic sample of a 1 : 1 mixture of POP and SOS with additives of AOA and BOB. An addition of small amounts of AOA and BOB caused both a change in the transformation circuits from β'→ sub β→X→β to β'→intermediate→β, and a decrease of the duration for the complete conversion into the most stable β form. Whereas the transformation was delayed with increasing an amount of the additives.