Dynamic mechanical properties of strontium stearate

The dynamic modulus (G′) and the loss (G″) were measured as a function of temperature for strontium stearate which undergoes successive phase transitions from crystal (Cr)–unknown liquid crystalline (lc) (X), rhombohedral lc (R), body-centered cubic (Q) and hexagonal lc (H) phases. This Letter shows that in the Q phase only, G′ and G″ undergo a thermal hysteresis and in the Q phase, the G′ and G″ values were smaller during cooling from the H phase than during heating from the R phase and G′ was smaller than G″ in the cooling process. From these results, the formation and structure of the Q phase are discussed.