モノグリセリドの多形 (第8報)

2成分系固溶体

抄録

Mechanism for the formation of a solid solution and its modification phenomenon were examined in the binary systems of C₁₈-C₁₆, C₁₈-C₁₄, C₁₈-C₁₂, and C₁₆-C₁₄, using differential scanning colorimetry (DSC) and infrared (IR) spectroscopy.
1) Binary systems of C₁₈-C₁₆, C₁₈-C₁₄, and C₁₆-C₁₄ form continuous solid solution in either metastable state or stable state. At transition, they transit from sub-α and α-type solids to β-type solids, and this behavior was similar to that shown by 1-monoglyceride alone. C₁₈-C₁₂ system does not form a solid solution, and C₁₈ and C₁₂ were found to undergo transition independently.
2) Phase diagrams of C₁₈-C₁₆, C₁₈-C₁₄, and C₁₆-C₁₄ systems showed a similar pattern. Transition curve from sub-α to α-type was characteristic, the lowest temperature appeared at a specific composition ratio of the two components, and this temperature differed according to the composition ratio of the two camponents. Since C₁₈ and C₁₂ did not dissolve with each other, transition curves of C₁₈ and C₁₂ were different curves.
3) Transition rate was affected by the molecular chain length comprising the binary system, and became slower in the order of C₁₈-C₁₆, C₁₈-C₁₄, and C₁₆-C₁₄. The transition rate was the fastest in the case of short-chain monoglyceride containing 510% of longchain monoglyceride, but the rate becomes slower as the transition temperature from α to β-type becomes higher, so that, in general, the rate becomes faster with larger amount of short-chain monoglyceride contained in the long-chain monoglyceride, and became slower in the case of contrary.