This study deals with the surface modification of polymer fine powders by a high speed impact treatment method utilizing interactive mixing. The interactive mixtures are dispersed by air flow (100 m/s) and are hit repeatedly with the striking pins revolving at 16000 rpm for 5 minutes. Many polymethylmetacrylate particles (0.3μm) softened and melted, and as a results encapsulated each Nylon 12 particle (5μm). And also, Nylon 12 coated polyethylene particles (250μm) can be prepared.
The photocatalytic activities of SiO2-coated TiO2 particles were investigated in the formic acid suspension system. The SiO2 films were precipitated onto TiO2 particles from an silca gel-saturated solution of H2SiF6. It was found that the SiO2-coating effectively decreased the photocatalytic activity of the TiO2 particles, especially anatase. The results were discussed on the basis of the mechanism of the reaction proposed.
Ultrafine iron oxide particles from sublimated chelate, acetylacetonate of Fe (III) were prepared by means of microwave plasma CVD method. The preparation was carried out in two stages. The first stage, the primary treatment, is the process where the sublimated chelates are deposited on the inner wall of the reactor. The second stage, the secondary treatment, is the process in which the remaining organic components are removed from the deposited substances utilizing the oxidation and decomposition action of oxygen plasma. The results showed that while a pressure of 3 Torr seemed to be the most appropriate condition in the primary treatment process, a pressure of 5 Torr showed highest efficiency in the secondary treatment process. The diameter of the particles obtained was around 10 nm as observed from TEM micrographs of particles.
Non-ionic blue trisazo dyes having the same acceptor and conjugating bridge, and different kinds of donor with intramolecular charge-transfer chromophores were synthesized and their color-constitution relationship, dichroism and solubility in liquid crystal were investigated. Their λmax lie at 626-645 nm and dyes absorbed in the broad region of 500-800 nm in LC. The deep blue dyes, which have 1-heptyl-2,2,4,7-tetramethyl-1,2,3,4-tetrahydroquinoline as a donor, have an appropriate dichroism and solubility in LC and can be practically used. On the other hand, the dyes derived from 1-alkylaminonaphthalene and julolidine have better dichroism, but generally have lower solubility and their applications are restricted.
A method to prepare TiO2-Al2O3 doubly coated mica powders has been developed by utilizing homogeneous precipitation method. The laminated structure of Al2O3/TiO2/Mica was confirmed by analyzing the precipitation reaction process and by the surface analysis of the resulting powders with ESCA. A computor controlled goniospectrophotometer was assembled and the optical properties of the powder surfaces were measured. When Al2O3 percentage in coating materials (TiO2+Al2O3) was low, the reflectance around the specular angle was high and the color of reflected light was purplish blue. On the contrary, when the Al2O3 percentage reached above 50%, the reflectance decreased in the whole viewing angle range and the color of reflected light came close to achromatic. Thous, the powder surface became to show the appearance of natural luster. TiO2-Al2O3 doubly coated mica showed higher whiteness than mica itself. In addition, the degree of color darkening by wetting with oil was less than mica. As a result, it is concluded that TiO2-Al2O3 doubly coated mica has the optical properties fit for cosmetic extender pigment.
The acid-base concept was applied to design pigment-dispersing resins in order to attain strong interactions between pigments and resins. The acid-base amounts of each pigment were determined by nonaqueous titration method. Pigment-dispersing resins were prepared by acid-base modification of a main binder of paint so as to be compatible with the main binder. In the case of an acidic pigment, dispersion rate and the degree of dispersion at equilibrium were increased by introduction of basic compounds such as melamine resins and N-2-hydroxy ethyl ethylene imine (HEEI) into the main binder. On the other hand, for a basic pigment, introduction of HEEI into the main binder resulted in the decrease in both of the rate of dispersion and the degree of dispersion at equilibrium.