Journal of the Japan Society of Colour Material

Two Different Chlorination Processes of Copper Phthalocyanine and Their Effect on the Mold Shrinkage of Colored Plastics

Shigeru SUZUKI, Hitoshi MAKI, Naoki HAMADA

2003 Volume 76 Issue 11 Pages 413-420
Published: November 20, 2003
Released on J-STAGE: November 20, 2012

DOIhttps://doi.org/10.4011/shikizai1937.76.413

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Two chlorination processes of copper phthalocyanine (CuPc), homogeneous system based on eutectic blend composed of AlCl₃ and NaCl (“AlCl₃ process”) and heterogeneous system in trichlorobenzene (“TCB process”) are known. The product of the former process is quite effective in suppressing the mold shrinkage of colored polyethylene, while the latter exhibits no noticeable effect. The mechanism of the above different effect has been investigated from the standpoint of reaction products in both processes. The degree of chlorination as well as chlorinated positions is well defined in chlorinated CuPc prepared by AlCl₃ process. On the other hand, the degree and the position of chlorination are broadly distributed in chlorinated products from TCB process. On the basis of the above results, both well-defined degree of chlorination and well-defined chlorinated position in CuPc products prepared by AlCl₃ process are concluded to be the key factor to the suppression of nucleation effects in polyethylene, leading to the successful suppression of the mold shrinkage of colored plastics.

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Preparation of Silver-, Platinum-, and Palladium-PAMAM Dendrimer Nanocomposites and Their Catalytic Activities for Reduction of 4-Nitrophenol

Kunio ESUMI, Ryoko ISONO, Tomokazu YOSHIMURA

2003 Volume 76 Issue 11 Pages 421-427
Published: November 20, 2003
Released on J-STAGE: November 20, 2012

DOIhttps://doi.org/10.4011/shikizai1937.76.421

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Metal (silver, platinum, and palladium) -dendrimer nanocomposites are prepared in aqueous solutions by using poly (amidoamine) (PAMAM) dendrimers (generation ; 1.5, 3.0, 3.5, 4.0, 5.0 and 5.5) with carboxyl or amino terminal groups, and their average particle diameters are 5-7 nm for silver, 1-2 nm for platinum, and about 2 nm for palladium depending on the concentration of the dendrimers, but not the generation of the dendrimers. In particular, stable metal-dendrimer nanocomposites are obtained at lower dendrimer concentrations using the dendrimers with carboxyl terminal groups compared to those with amino terminal groups. It is suggested that the metal-dendrimer nanocomposites are formed by adsorbing dendrimer molecules on the metal nanoparticles. Studies of catalytic reduction of 4-nitrophenol by the metal-dendrimer nanocomposites with sodium borohydride reveal that the rate constant depends on the concentration of the dendrimers added as well as the generation of the dendrimers. Furthermore, the rate constants are found to be dependent on the type of terminal groups. Among three metaldendrimer nanocomposites, palladium-dendrimer nanocomposites are also found to be most efficient catalysts for the reduction of 4-nitrophenol with sodium borohydride.

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Interactions between Thiol-modified Gold Nanoparticles and a Cationic Polyelectrolyte

Satoshi KUNIYASU, Tomokazu YOSHIMURA, Kunio ESUMI

2003 Volume 76 Issue 11 Pages 428-433
Published: November 20, 2003
Released on J-STAGE: November 20, 2012

DOIhttps://doi.org/10.4011/shikizai1937.76.428

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The interactions between gold nanoparticles modified with mercaptoacetate and a cationic polyelectrolyte, poly (dimethyldiallylammonium chloride) (PDC) have been investigated. As a comparison, a system containing the modified gold nanoparticles and a cationic surfactant, hexadecyltrimethylammonium bromide (HTAB) is also studied. The average sizes of the modified gold nanoparticles used are 5.7 and 12.9 nm, respectively. Most of experiments have been performed under a fixed concentration of the modified gold nanoparticles with various PDC concentrations at pH 3 and 8. UV-vis spectroscopy and transmission electron spectroscopy reveal that at pH 8, the modified gold nanoparticles with small size are gradually aggregated with an increase of PDC concentration, whereas those with large size are aggregated at low PDC concentration, but at higher PDC concentration the gold nanoparticles are well separated. At pH 3, the modified gold nanoparticles for both sizes show a dispersion-flocculationredispersion sequence. These interactions are predominantly induced by the electrostatic attractions between negatively charged nanoparticles and positively charged PDC which are affected by pH. In the case of the modified gold nanoparticles-HTAB system, the modified gold nanoparticles show a dispersion-flocculation-redispersion sequence. The redispersion occurs by the formation of HTAB bilayer on the nanoparticles.

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Recent Regulation of VOC Emission from Automotive Finishing Industry and Technical Trend of Countermeasures

Hidetoshi YAMABE

2003 Volume 76 Issue 11 Pages 434-438
Published: November 20, 2003
Released on J-STAGE: November 20, 2012

DOIhttps://doi.org/10.4011/shikizai1937.76.434

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White Light Emitting Diode and its Related Phosphor

Tsutomu ODAKI, Kazuaki HASHIMOTO, Katsumi YOSHIDA, Yoshitomo TODA

2003 Volume 76 Issue 11 Pages 439-444
Published: November 20, 2003
Released on J-STAGE: November 20, 2012

DOIhttps://doi.org/10.4011/shikizai1937.76.439

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Color Detection for Coloring Substance

Masuhiko MAEJIMA

2003 Volume 76 Issue 11 Pages 445-451
Published: November 20, 2003
Released on J-STAGE: November 20, 2012

DOIhttps://doi.org/10.4011/shikizai1937.76.445

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