2015, Vol.27, No.4

Textile Coloration and Finishing KCI Impact Factor : 0.0

pISSN : 1229-0033 / eISSN : 2234-036X
https://journal.kci.go.kr/ksdf

The effects of synthesis conditions on characteristics of the calcium-azo complex pigment, C.I. Pigment Red 57:1, were studied. It was mainly considered that the industrially required synthesis conditions for lowering electrical conductivity of the pigment solution keeping pigment quality such as particle size and color characteristics. Three parameters were chosen as control factors during the synthesis. The first was the amount of hydrochloric acid added to transform sodium nitrite into nitrous acid. The second was the amount of calcium chloride added to insolubilize the synthesized azo dye. The final factor was pH control during the coupling reaction. The electrical conductivity and pigment aggregate particle size were dependent on the amount of hydrochloric acid and calcium chloride. Higher HCl concentration gave brighter yellowish-red color because of smaller particle aggregate size and narrower size distribution. Amount of charged ions in the synthesis process might affect the “lake” formation resulting different particle aggregate size and color shade.

The effect of salt milling process on the crystal size, morphology, and color characteristics of C.I. Pigment Red 57:1 was studied. The primitive morphology and color properties of the pigment after synthesis were studied in the former series work. The size and morphology of primary particles and the second aggregation features should be considered because they are very important to determine pigment quality. We compared the primary morphology of pigment particles before drying with the secondary aggregated morphology of pigment particles after drying and salt milling process. Morphological properties were investigated by particle size analysis, X-ray diffraction, and scanning electron microscopy and color measurement was carried out. Significant reduction in particle size as well as enhanced crystallite size after salt milling process was observed. This result might give a difference in color of the pigment, turning into brighter and more blue-toned red color. It was revealed that synthesis condition affect the morphology and color of the pigment even after milling. Increase in HCl concentration in the synthesis process enhanced crystal size and quality forming bluer-red pigments but an increase in CaCl2 concentration resulted in more amorphous crystals forming darker-red pigments after salt milling.

Two new D-π-A dyes were synthesized by the condensation reaction between active methyl and aromatic aldehyde and its biothiol sensing properties in DMSO/water were investigated by UV-vis spectroscopy. Upon addition of Hg2+, the solution of D-π-A dyes showed color change and the absorption band shows a formation of a dye-Hg2+ coordination complex. These dyes exhibited high selectivity for Hg2+ as compared with other cations. The dye-Hg2+ could be recovered by adding glutathion(GSH). The absorption intensity of dye-Hg2+ increased only by the addition of glutathione(GSH). The competition experiments revealed that no obvious interference was observed by performing the titration with the mixture of glutathione(GSH) and other amino acids. The results indicated that these D-π-A dyes were highly selective for glutathione(GSH) detection.