We have prepared porous clay membranes from the clay gels using a freezing and a vacuum drying processes. The SEM observations revealed that the membranes possess channel-like holes whose diameter in between several to several ten micrometers. The oxygen permeability and acetaldehyde absorption tests indicate that the holes are penetrated from the bottom to the top of the membrane although they have not ideal strait channels. The mechanism of the formation of the holes is proposed; the freezing process yields ice-seeds on a substrate and the seeds grow along a direction to perpendicular to the substrate. The resultant needle-ice crystals lead to formation of channel-like penetrated holes in the membrane. Furthermore, composite membranes with the penetrate holes could be prepared with ZSM-5 or mordenite particles. As the result, we have developed novel-clay-based-membranes with many penetrate holes, which widen to apply for the reactor or filter devices.

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1,6-di(N-methyl-pyridinium-3-yl)-pyrene(m-Py^<2+>) was synthesized. Photochemical properties were observed for m-Py^<2+> itself and m-Py^<2+>/clay complexes. Judging from Lambert-Beer plot analysis, m-Py^<2+> molecules adsorb on the clay surface without aggregation up to 60 % versus cation exchange capacity of the clay. m-Py^<2+> molecule emits fluorescence from excimer on the clay surface. An energy transfer reaction from excited singlet m-Py^<2+> to the ground-state p-TMPyP on the clay surface was examined. The maximum energy transfer efficiency was 13 %. These findings indicate that pyrene derivative is expected as energy donor which can absorb shorter wavelength light in the visible region towards the establishment of artificial light-harvesting system.

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We studied the sintering characteristics and reducing weight of porcelain due to the addition of GHM (Glass Hollow Microsphere). 1.0〜2.5 wt% of GHM-A, GHM-B were added to the starting materials of white porcelain composition to reduce weight of green compacts by slip casting. The green compacts with various amount of GHM were heated up to 1229 ℃, 1254 ℃ at 3 ℃/min, maintained for 30 minutes. GHM (A, B) was added up to 2.5 wt% at maximum and their sintering behaviors were analyzed. As a result, sintering starting points of green compacts with GHM appeared to be accelerated due to the low melting point of GHM. Also, the pore formation produced during the sintering process still remained which reduced the shrinkage rates of green bodies by 6.5% and increased pyroplastic deformation by 9.8 mm. In the microstructure analysis, pores were equally formed inside the sintered body and the density decreased 0.6〜1.0 g/cm^3 due to these pores.

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Lightweight pottery was manufactured by emitting gas from ceria at a high temperature to form pores during the sintering process. In the bone china sintering method, the first sintering temperature is 1250-1280℃, which is higher than that of general porcelain. Using this sintering condition, pores can be formed by adding a material that emits gas at a high temperature. The materials that emit gas to form pores during the sintering process include AlOOH, HAp, Carbon and CeO_<2.> Of these materials, CeO_2, which emits gas at a high temperature, was mixed with the body clay. Because CeO_2 emits gas at 1100℃〜1300℃, at which the sintering of green body starts, closed pores were formed in the sintered body. CeO_2 was added by 5 wt% and 10 wt% compared with commercial porcelain material and sintering was conducted at up to 1300℃. The density of the sintered body decreased with the decrease in the temperature and added content of ceria. The density of the sintered body with CeO_2 fired at 1300℃ decreased by more than 30% than that of general white porcelain. The diameters of the pores formed in the microstructure in the sintered body were mostly 30〜50μm.

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