Trichromatic Vat Dyeing of Cationized Cotton

This article deals with cationization of cotton during mercerization and its effects on trichromatic vat dyeing. If cationization is carried out during the after-treatment, regardless of cotton pretreatment, the reaction takes place on the surface and blocks cellulose groups, subsequently resulting in uneven coloration. However, when cationization is carried out with an epihalohydrin during the mercerization process, new cellulose is formed in which the cationic compound is uniformly distributed and trapped between cellulose chains, resulting in uniform coloration after the dyeing process. The reaction time for the process during mercerization is 24 h, thus a more favorable process was researched. Based on electrokinetic analysis, it was found that 5 h was sufficient for the reaction with 3-chloro-2-hydroxypropyltrimethyl ammonium chloride (CHPTAC). The cationization of cotton contributed to the processes of vat dyeing. The change in charge upon cationization resulted in very high adsorption of vat-dye anions, indicating that ionic bonding occurred in addition to van der Waals forces. The color depth improved by more than 10 times. It should be emphasized that the colors with higher chroma and targeted color hue, especially in trichromatic dyeing, were obtained on cationized cotton, in contrast to standard cotton fabrics. The color differences obtained under the different light sources indicate the occurrence of metamerism. Considering the color fastness to laundering, vat-dyed cationized fabrics of all colors may be used in hospitals or other environments where high hygiene and oxidative bleaching are required.

2,9-Dibenzo[b,def]chrysene as a Building Block for Organic Electronics

In this article, a new series of conjugated polymers based on a low-cost, easily accessible vat dye called Vat orange 1 or 2,9-dibromo-dibenzo[b,def]chrysene-7,14-dione, have been prepared. This compound was made...

SYNTHESIS OF VAT BLUE ANTHRAQUINONE (INDANTRONE) DYE WITH IMPROVED SURFACTAN

The results of the study of the process of synthesis of vat dye from chemical components isolated from coke oven gas and resin after coking coal are shown. The schemes of reactions of obtaining intermediates for the synthesis of the dye are given. block diagrams of chemistry of technological operations are made, physicochemical color properties of this dye are studied.

Colour management in circular economy: decolourization of cotton waste

Purpose While aiming to create methods for fibre recycling, the question of colours in waste textiles is also in focus; whether the colour should be kept or should be removed while recycling textile fibre. More knowledge is needed for colour management in a circular economy approach. Design/methodology/approach The research included the use of different dye types in a cotton dyeing process, the process for decolourizing and the results. Two reactive dyes, two direct dyes and one vat dye were used in the study. Four chemical treatment sequences were used to evaluate colour removal from the dyed cotton fabrics, namely, HCE-A, HCE-P-A, HCE-Z-P-A and HCE-Y-A. Findings The objective was to evaluate how different chemical refining sequences remove colour from direct, reactive and vat dyed cotton fabrics, and how they influence the specific cellulose properties. Dyeing methods and the used refining sequences influence the degree of colour removal. The highest achieved final brightness of refined cotton materials were between 71 and 91 per cent ISO brightness, depending on the dyeing method used. Research limitations/implications Only cotton fibre and three different colour types were tested. Practical implications With cotton waste, it appears to be easier to remove the colour than to retain it, especially if the textile contains polyester residues, which are desired to be removed in the textile refining stage. Originality/value Colour management in the CE context is an important new track to study in the context of the increasing amount of textile waste used as a raw material.

Degradasi Zat Warna Orange-F3R dan Violet-3B secara Sonolisis Frekuensi Rendah dengan Penambahan Katalis C-N-Codoped TiO2

Zat warna orange-F3R dan violet-3B merupakan zat warna organik sintetis turunan vat yang bersifat non-biodegradable. Degradasi kedua zat warna ini telah dilakukan secara sonolisis dengan penambahan katalis semikonduktor TiO2 anatase yang didoping karbon dan nitrogen. Proses sonolisis menggunakan iradiasi ultrasonik dengan frekuensi 35 kHz. Massa katalis optimum yang diperoleh untuk sonolisis zat warna orange-F3R adalah 9 mg dan 6 mg untuk violet-3B. Persen degradasi meningkat secara signifikan dengan penambahan katalis yaitu dari 8.3% menjadi 36.2% untuk sonolisis zat warna orange-F3R selama iradiasi 180 menit. Sedangkan, dengan waktu iradiasi yang sama persen degradasi dari zat warna violet meningkat dari 5.8% menjadi 34.2% setelah penambahan katalis. Kata kunci: C-N-codoped TiO2, sonolisis, ultrasonik, vat Orange-F3R and violet-3B are non-biodegradable synthetic organic dyes. The degradation of these two dyestuffs has been done by sonolysis process with the addition of semiconductor TiO2 anatase catalyst which is doped by carbon and nitrogen atoms. The sonolysis process used ultrasonic irradiation with a frequency of 35 kHz. The optimum catalyst mass obtained for the orange-F3R dye sonolysis was 9 mg and 6 mg for violet-3B. The percentage of degradation increased significantly with the addition of the catalyst; it was from 8.3% to 36.2% for the orange-F3R dye during irradiation for 180 min. Meanwhile, by the same irradiation time, the degradation percentage of violet dye increased from 5.8% to 34.2% after the addition of the catalyst. Keywords: C-N-codoped TiO2, sonolysis, ultrasonic, vat-dye.

Recent advances in the chemistry of vat dyes for organic electronics

This review presents an overview of recent developments in the area of vat dye chemistry for the preparation of π-conjugated molecules and polymers for organic electronic applications.