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Volume 72, Issue 2
Displaying 1-7 of 7 articles from this issue
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Yutaka ISHIGAMI, Midori GOTO, Takashi MASUDA, Yasuomi TAKIZAWA, Shiger ...1999 Volume 72 Issue 2 Pages 71-77
Published: February 20, 1999
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSThe molecular and crystal structure of curcumin was investigated by X-ray analysis at a room temperature of 23°C. Anhydrous crystal was obtained from methanol. The crystal is monoclinc, and the space group is P2/n with Z=4.The cell dimensions are as follows, α = 12.688 (3) Å, b = 7.2061 (5) Å, c = 19.897 (5) Å, β = 95.28° (1). In this structure, the molecules are aggregated intermolecularly into infinite chains linked between the phenyl OH and the carbonyl O (or -OH). The hydrogen bond between O1-O4 was weaker than that found in the previous work due to a longer intermolecular distance. It could be suggested that the enol-ring was found to be more asymmetric than in the previous work. Such a network formation is attributed to intermolecular hydrogen bonds between terminal phenol moieties of curcumin assembling a fibrous structure. Futhermore, it was found that the hydrogen bonding played an important role in the molecular packing of crystal curcumin. Crystal curcumin interacted with solids and showed potential for use as an environmental probe for the estimation of solid surfaces on the basis of its fluorescent properties and interactions with polar materials.View full abstractDownload PDF (674K) -
Yasushi KAKIZAWA, Hideki SAKAI, Tetsuo SAJI, Norio YOSHINO, Yukishige ...1999 Volume 72 Issue 2 Pages 78-87
Published: February 20, 1999
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSWe have examined micelle formation of a long chain alkyl quaternary ammonium salt with a ferrocenyl group introduced at the end of the hydrophobic chain, (11-ferrocenyl) undecyltrimethylammonium bromide (FTMA), and the effect-of oxidation of the ferrocenyl group on the solubilization of benzene derivatives by FTMA micelles.
Determinations of the critical micelle concentration (cmc) of FTMA by the surface tension method revealed that the reduced form (FTMA+) has a cmc value of 7 x 10-5 mol/L while the oxidized form (FTMA2+) exhibits its cmc at 1 x 10-3 mol/L, about 15 times higher than that for the reduced form. At 50% oxidation of FTMA+, the cmc was 6 x 10-4 mol/L, an intermediary value of those for FTMA+ and FTMA2+. The changes in cmc caused by the oxidation were confirmed by electroconductivity measurements, thus demonstrating that the cmc shifts towards the higher concentration side with proceeding oxidation of the ferrocenyl group.
Investigations were then made of the solubilization in aqueous FTMA solutions of three benzene derivatives with different solubilities in water, ethylbenzene (EtBz), 2-phenylethylalcohol (PEA), and benzyl acetate (BA). The maximum amount solubilized was found to decrease for all solutes with progressive oxidation of FTMA. Similarly, a decrease was also found in the number of moles of solute per mole of surfactant constituting micelles (solubilizing capacity) with rising degree of oxidation. This was ascribed to a decrease not only in the number of FTMA molecules forming micelles but also in the number of sites of the solubilization in micelles as the oxidation proceeded. Examination of the effect of oxidation of the ferrocenyl group on the solubilization equilibrium constant of solute showed that FTMA oxidation makes it difficult for all three aromatic compounds to be solubilized.View full abstractDownload PDF (1187K) -
Osamu KUROKI, Masaaki MIZUGUCHI, Masahiro NOGUCHI, Satsuo KAMATA1999 Volume 72 Issue 2 Pages 88-94
Published: February 20, 1999
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSSilica microspheres containing UV-shielding materials were prepared by impregnation method and their shielding ability was investigated. The UV-shielding materials, CeO2, ZnO, and TiO2, were supported 1-20% on the silica microspheres, of which size was 1, 5, and 10, μm. In general, the greater the content of the UV-shielding material was or the smaller the particle size of silica microsphere was, the greater the UV-shielding ability was. Silica microsphere prepared by impregnation method shielded more UV and transmitted more visible region than that by suspension method. Silica microsphere containing ZnO prepared by suspension method did not shield UV, while that prepared by impregnation method did.View full abstractDownload PDF (917K) -
Eiichi TSURUTA1999 Volume 72 Issue 2 Pages 95-101
Published: February 20, 1999
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSDownload PDF (1028K) -
Theodor ENGBERT, Manfred BOCK, Osamu KIRIHARA1999 Volume 72 Issue 2 Pages 102-107
Published: February 20, 1999
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSThe quality demands placed on automotive top coats have increased constantly in past years. Resistance to acid rain, scratch resistance, gloss and optical performance of the coating, both when new and after years of use, have come to the fore as the main functional properties.
Different two-pack and one-pack polyurethane systems have been evaluated for their contribution to scratch and mar resistance as well as acid etch resistance of the resulting automotive finish. Special attention was given to the aspect of ageing.View full abstractDownload PDF (1013K) -
Shigeyuki MORI, Takashi IGARI1999 Volume 72 Issue 2 Pages 108-114
Published: February 20, 1999
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSDownload PDF (985K) -
Masahiro YOKOSUKA, Kei TAKEBAYASHI1999 Volume 72 Issue 2 Pages 115-123
Published: February 20, 1999
Released on J-STAGE: November 20, 2012
JOURNAL FREE ACCESSDownload PDF (1495K)
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