Synthesis of Novel Reactive Dyes for Textile Applications

Abstract

The present project was designed to synthesize six heterofunctional reactive dyes with the objective to achieve alternative commercial products having better exhaustion, fixation on the cotton fabric with improved fastness properties on the through exhaust and pad dyeing methods. Physico-chemical method was used for the purification of thenovel azo reactive dyes and characterization of the six novel dyes was carried out for the structure elucidation through the analytical techniques including FTIR and mass spectrometry (ESI-MS). The effect of different dyeing process parameters (temperature, time and pH) on the dyeing quality was optimized for the pad thermosol dyeing through classical approach. Three important process parameters (salt, temperature and alkali concentration ) main and interactive effects were investigated through the Central Composite design on the exhaustion and fixation of novel dyes and results were analyzed by ANOVA and p-values. The exhaustion percentage at optimized conditions was 72 for D-1, 69 for D-2, 84 for D-3, 81 for D-4, 84 for D-5 and 87 for D-6. Similarly the fixation results were 67, 62, 79, 77, 79, and 82 for synthesized azo reactive dyes D-1 to D-6 respectively. From the results it was clear that D-6 showed highest exhaustion and fixation percentage while minimum results were obtained for dye D-2. Laboratory scale screen printing machine was used for the printing of six synthesized reactive dyes in paste form using 3% w/w. Color strength of the printed samples was determined and it was less than 60 percent after washing of samples. The colorimetric data of the synthesized dyes was determined with the help of spectraflash spectrophotometer by subjecting the dyed fabric to CIELAB and LCH system. Fastness properties (washing, rubbing, perspiration, light and chlorinated water) of the dyed fabrics were evaluated through ISO standard test methods. Fastness testing demonstrated significant results ranges from 3 to 5 on the grey scale. The results were compared with the commercial reactive dye Reactive red 195 and these are in close agreement. Ultraviolet protection factor (UPF) for the dyed fabric at 2% dye shade was also evaluated which was excellent to very good. Advanced oxidation processes were used for the degradation studies of the synthesized dyes and analytical studies of the degraded samples were carried out using UV-Vis and FTIR spectroscopic techniques which confirms the degradation of the dyes. Results obtained showed the commercial viability of the synthesized reactive dyes.