Projects / Programmes
Rationalization of textile finishing processes
| Code |
Science |
Field |
Subfield |
| 2.14.02 |
Engineering sciences and technologies |
Textile and leather |
Textile chemistry |
| Code |
Science |
Field |
| T400 |
Technological sciences |
Fine chemicals technology, colours |
| T470 |
Technological sciences |
Textiles technology |
rationalization, finishing processes, reactive dyes, UVA, B absorber, optical bleaching agent, decolouration of reactive dyes, lithium hydroxide, peroxyacetic acid, fading, kinetics of hydrolyses of reactive dyes.
Researchers (6)
Organisations (1)
Abstract
The research program is based on the possibility of changes of the chemical and supermolecular structure of the cellulose which enables to achieve greater sorbtion of the fibers and consequently higher level of the dyeing, using the reactive dyes. Different possibilities of the application of lithium hydroxide to prepare a cotton fabric before dyeing was examined. We found as the most effective the one minute treatment of cotton fabric in 5M LiOH in an ultrasonic generator at the temperature of 0°C.
A part of the research work was dedicated to the influence of natriumperborate, which is in the concentration at 0,07 g/l active oxygen present in washing powders, on the dyeings using different types of reactive dyes. The dyed samples of cotton fabric were treated in different periods of time in alkaline peroxide washing bath and fading was determined. The results show general low fastness of the red dyes at peroxide washing regardless to the reactivity system of the dyes.
The application of the UV A and B absorber Tinofast CUT /Ciba/ on the dyed samples as well as the combination with optical bleaching agent Ultraphor CK /BASF/ do not result improved fastness of the dyeings when washing following the ISO 105 CO 2 and CO 3 standards. But an important effect of UV A and B absorber was found by proving the fastness of the dyeings exposed to light. The most efficient was when simple yellow monochloro-s-triazine dye was used. The lightfastness increases even for two marks.
The influence of temperature on the kinetics of hydrolysis of red mono- and homobi-functional triazine reactive dyes was studied in alkaline buffer solution by means of high performance liquid chromatography. The rate constants of hydrolysis of the studied reactive dyes calculated by the pseudo-first order rate equation exponentially increase with temperature according to the Arrhenius equation. As the temperature is increased by 10°C the rate constants of the all studied dyes approximately increase by three times. With rising temperature the difference in the reactivity between the bis(fluoro-s-triazine) dye form and its deactivated monofluoromonohydroxybis-s-triazine form is a little decreased.
Performing physical and chemical researches between the reactive dyes and polyelectrolytes we studied the possibilities of the use of the iono-selective membrane electrodes as well as potentiometric titrations on the effectiveness some special synthetic polyelectrolytes at the decolouration of the reactive dyes solutions. It was found that potentiometric titrations help to determine the concentration of the ions bound to polyelectrolyte and that the binding process depends mostly of the structure and charge-density of the polyelectrolyte. In the case when the effectiveness of the flocculant depends mostly of the electrostatic interactions of opposite charged ions we can simply and with a certainty determine the effectiveness of the polyelectrolyte as the flocculant agent and the optimal concentration of the agent at decolouration of the reactive dyes solutions.
Conductometric method was used also at researching the interaction between dyes and opposite charged surfactants. The results show that anion dye and cation surfactant form nonconductive or less-conductive asociat. The molecular structure of surfactant is of great influence on the formation of the asociat. The association process is more distinctive by using the surfactant with longer hydrophobic chain.
The research program is based on the possibility of changes of the chemical and supermolecular structure of the cellulose which enables to achieve greater sorbtion of the fibers and consequently higher level of the dyeing, using the reactive dyes. Different possibilities of the application of lithium hydroxide to prepare a cotton fabric before dyeing was examined. We found as the most effective the one minute treatment of cotton fabric in 5M ...
