dc.description.abstract |
Dyeing of cotton with reactive dye requires very high concentration of salt. These salts
improve exhaustionby reduction of the repletion forces between the anionic dye and
hydroxyl functional groups of cotton. The salt is released after dyeing process and
increases salinity in drain water stream which affect human health and biodiversity in
water bodies. To eliminate salt consumption and enhance chicken feather waste
utilization, the research aims at using an eco-friendly approach of salt free dyeing of
cotton with two types of reactive dyes (cold and hot brand). The aim of the study was to
determine the effect of pre-treating the cotton fabric with extracted keratin hydrolysate
without the usage of salt on dye exhaustion, to optimize the dyeing parameters, compare
dye exhaustion values of hot and cold reactive dyeing and to analyse the effects of dyeing
parameters on colourfastness properties of pre-treated cotton fabric dyed with hot and
cold reactive dyes. Keratin hydrolysate was extracted from chicken feather waste. Cotton
fabric weighing 126.2 g/m 2 , 22.8 warps and 13 wefts per centimetre was used. Central
composite experimental design was used to optimize temperature and time in hot and cold
reactive dyeing. Dye exhaustion at maximum wavelength were evaluated using
spectrophotometer before and after dyeing pre-treated cotton fabric. The experimental
data was used to predict optimum dye exhaustion and optimum dyeing parameters. The
models for dye exhaustion in hot and cold brand reactive dyeing yielded P value of less
than 0.05 and coefficient of determination (R 2 ) of 0.9595 and 0.9444 respectively. The
model established optimum dye exhaustion of 52.9 % in hot and 48.3 % in cold reactive
dyeing. The study established optimum dyeing temperature of 69.7 0 C and time of 75
minutes in hot brand dyeing and 34.4 0 C and 45 minutes in cold brand dyeing. The cotton
fabric showed acceptable dye exhaustion in hot and cold reactive dyes in the absence of
salt. The untreated sample dyed in absence of salt exhibited low exhaustion values of 21.4
% and 28.7 % for cold and hot dye brands. This is lower when compared with the
exhaustion values of treated cotton fabrics. Therefore, the treated cotton fabric dyed in
the two types of reactive dyes exhibited high exhaustion values than the control sample
dyed in the presence of salt . The research further established that dyed keratin treated
cotton samples exhibited better wash fastness and rubbing fastness. While this research
has led to the utilization of chicken feather waste and reduction of salt usage in reactive
dyeing, more research should be carried out to assess the environmental impact of the
effluent which is generated from the salt free reactive dyeing of treated cotton fabrics. |
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