Photochemical isomerization of trans-azobenzene to ds-isomer, and its inverse cis-trans isomerization were investigated for the purpose of constructing a thermal energy storage system by conversion of solar light energy.Trans-cis photoisomerization of azobenzene in the cyclohexane solution proceeded with or without photosensitizers over a wide range of light in the ultraviolet and visible region. But the backward reaction from cis-to trans-form, which was predominant by the longer-wavelength light, set a limit to the progress of trans-cis conversion, and photochemical equilibrium was established at about 25 % conversion of mmv-azobenzene. Some devices to removethe conversion limit were examined. Cis-trans isomerization in the dark was carried out in the presence of immobilized metal porphine catalyst. Cotetraphenylporphine or Co-protoporphyrin fixed on polyethylene granules graft-polymerized with chloromethylstyrene was the most effective for the reverse reaction. This liberation of heat during the reaction was also analyzed from the kinetic point of view.

Photosensitized isomerization of norbornadiene to quadricyclene was investigated by using several photosensitizers such as toluene, acetone, acetophenone, benzophenone and a-naphthoquinone. The effect of wavelength on the quantum yield of quadricyclene and on the energy conversion efficiency was measured by using spectroirradiator. The formation of byproduct polymer in the presence of photosensitizers was also studied. The formation of polymers during irradiation, which prevents the repeated use of energy storage material, was effectively suppressed by the addition of several phenolic substances into norbornadiene.

Abstract--The pillaring of Na-montmorillonite with cationic oligomers of hydroxyaluminum (COHA) in the presence of an aqueous solution of polyvinyl alcohol resulted in the formation of a clay having a large surface area and pore volume. The pore-size distribution determined from a N2 adsorptiorddesorption hysteresis was narrow and centered at about 25 ~. The peak width at half height in the distribution curve was < 5 /~. As a result of delamination, the layer structure of the prepared clay was found from X-ray powder diffraction measurements to be lost. Short-range ordering, however, still existed in this delaminated clay, because exchangeable cations in the montmorillonite completely exchanged with A13+, a requisite step for pillaring.The order of adding the starting materials (Na-montmorillonite, polyvinyl alcohol, and COHA) greatly affected the surface area and the pore volume of the delaminated clay. Two orders of addition (Namontmorillonite, then COHA, then polyvinyl alcohol; and COHA, then Na-montmorillonite, then polyvinyl alcohol) gave no measurable surface area and pore volume. Two other orders of addition (polyvinyl alcohol, then COHA, then Na-montmoriUonite; and polyvinyl alcohol, then Na-montmorillonite, then COHA) gave surface areas of 107 and 160 mVg and pore volumes of 0.13 and 0.29 cm3/g, respectively. The amounts of the COHA solution and polyvinyl alcohol added greatly influenced the surface area and pore volume of the delaminated clay. Both properties increased monotonically with increasing amount of added polyvinyl alcohol, and increased to a maximum and then decreased with increasing amount of added COHA solution. The maximum surface area of the prepared delaminated clay was 330 m2/g.

U n i v e r s i t y 4-4-37, Takeda, Kofu-shi 400 * Government Industrial Research Institute N a g o y a An additive effect on the pressureless sintering of boron carbide is investigated. Some additive species, Al, TiB2, and AlF3 show a remarkable densification effect upon B4C. The Al-addition provides the best sintered body with the highest bulk density of 95% by means of the firing condition of 2200•Ž for 30min under Argon flow. An addition of SiC prevents the densification process. The additive species except for SiC tend to restrain the grain growth and the pore growth, acting probably as an inhibitor for the surface matter transport.

SynopsisTriethoxyvinylsilane-styrene and triethoxyvinylsilane-methyl methacrylate binary monomers were polymerized by chemical initiation or by y-ray irradiation in the presence of silica gel, fire brick, quartz wool, and glass beads. The amount and composition of the polymers grafted to silicates were analyzed by using pyrolysis gas chromatography. When triethoxyvinylsilane alone was subjected to the reaction with silicates, condensation occurred irrespective of the initiating means, and the extent of the reaction was almost proportional to the specific surface area of the silicate. When binary monomer mixture was applied, incorporation of styrene or methyl methacrylate into the grafted polymer was observed whenever a monomer mixture of high styrene or methyl methacrylate content was submitted to the reaction. On each silicate, the relationship between the composition of polymer grafted on it and that of monomer showed a similar pattern in spite of the great difference of the specific surface area. Almost no participation of styrene or methyl methacrylate was observed when the silicate preirradiated in air or under vacuum was heated with the binary monomer mixture. It was concluded that triethoxyvinylsilane reacts with silicates by condensation and that some of the pendent vinyl groups on the silicates are incorporated into the copolymer with styrene or methyl methacrylate.