Proceedings of the Japan Academy, Series B

Partitioning behaviors of Mn, Co and Ni between iron hydride and mantle minerals (olivine, pyroxene and magnesiowustite) under high pressure were experimentally investigated at 1400°C and 3-11GPa. The present experimental results showed that the siderophile nature of Co and Ni, and the lithophile nature of Mn decrease under high pressures: all the observed metal/mineral partition coefficients, K'=(X_i/X_Fe)^metal/(X_i/ X_Fe)^mineral, i=Mn, Co and Ni, approach 1 with increase in pressure. K' also depends on the composition of the mineral phase: K' decreases with an increase in MgO mol fraction. From these experimental results, it is expected that the observed upper mantle elemental abundance may be explained by the equilibrium between metal and silicates under extremely high pressure.

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Synthesis of side-chain liquid-crystalline polymers with narrow molecular weight distribution and controlled molecular weight from mesogenic methacrylates (MEM) with cyano and/or ester groups in their mesogen was achieved through their photopolymerization using (5, 10, 15, 20-tetraphenylporphinato)aluminum methyl (MTPP) as a photosensitizer. The poly(MEM) obtained using MTPP have slightly higher contents of syndiotactic triads and lower contents of isotactic and heterotactic triads than those obtained with a radical initiator. Further, it was found that the tacticities of poly(MEM) are not much different from those of poly(methyl methacrylate) for both the polymerization systems, i.e., polymerizations with MTPP and the radical initiator. Copolymerizations of MEM initiated with MTPP and the radical initiator yielded copolymers with same compositions as those of monomer mixture in feed. Possibility for the control of molecular weight and its distribution of the copolymers obtained using MTPP has been shown. These results opened the way for the synthesis of block copolymers with liquid-crystalline polymeric chain as one component which are considered to form liquid crystals with unique properties, e.g., dimensional stability.

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