Mitsuharu Fukaya

Apatite Formation on TiO2 Photocatalyst Film in a Pseudo Body Solution

TiO2 photocatalysts film supported on glass plate was soaked in a pseudo body solution (PBS) containing excess phosphate ions. The surfaces were characterized by scanning electron microscopy, energy-dispersive spectroscopy, thin-film X-ray diffraction, and Fourier-transformed infrared methods. After soaking in the pseudo body solution for 1 day, a bone-like apatite layer was formed on the surface of the TiO2. The apatite layer was approximately 0.7 mm thick and made up of thin plate-like crystals. The haze values of dry and wet specimens were 28.47 and 9.51%, respectively. The apatite-coated TiO2 thin film could be used for antibacterial and environmental purification purposes.

Radiation damages of organic materials at 4 K: An ESR study of polyethylene and related hydrocarbons

Abstract To characterize the radiation damages produced at 4 K in polyethylene and related hydrocarbons, a series of studies have been carried out by using electron spin resonance(ESR) spectroscopy. It has been found that the local concentration of radiation induced paramagnetic species is considerably higher in the irradiation at 4 K than that at 77 K. The causes of this irradiation temperature effect on the spatial distribution of radicals have been extensively studied. It is suggested that the suppression of hydrogen atom migration and the reactivity of hydrogen atoms at 4 K play an important role in the low temperature radiation damages of saturated hydrocarbons. In the present paper the results previously and newly obtained are surveyed and discussed as a whole.

Even–odd alternation of the fromation of chain end alkyl radicals in irradiated crystalline alkanes; e.s.r. evidence

Even–odd alternation of the e.s.r. spectra of a series of irradiated linear alkanes starting from n-C11 H24 is found to be due to the prominent chain end alkyl radical formation in odd members of the series, suggesting that the radiation chemistry of crytstalline alkanes may be affected by the cyrtystal structure, e.g. by molecular packing and alignment.

Formation of allylic and hydrogen addition radicals in tiglic acid (αβ-dimethylacrylic acid) irradiated at 77 K as studied by ESR

Abstract Nearly equal amounts of allylic and hydrogen addition radicals are formed in tiglic acid [ CH 3 CH = C ( CH 3 ) COOH ] irradiated at 77 K by loss of a hydrogen atom from the β methyl group and by addition of a hydrogen atom to the β carbon atom, respectively. Unlike usual unsaturated carboxylic acids, the origin of the added hydrogen atom is likely from the C-H hydrogen rather than the acidic one, because deuterium substitution of the acidic hydrogen does not result in deuterium addition. In β-methyl substituted acrylic acids, deprotonation of the primary cation seems to take place at the β methyl group forming allylic radicals and the detached proton adds to the primary anions forming hydrogen addition radicals [ CH 3 CH 2 - C ( CH 3 ) COOH ], although a possibility of homolytic scission of the C-H bond in the β methyl group followed by the hydrogen atom addition to form the above mentioned two radicals cannot be excluded. The drastic difference from the acidic proton addition to the molecular anion in many unsaturated carboxylic acids may be ascribable to the existence of β methyl group which leads to the formation of persistent allylic radicals.