New dyeing technique for enhancing colour strength and fastness properties of cotton fabric dyed with natural dyes

279-282Dyeing behaviour of four different natural dyes extracted from the leaves collected in a sustainable manner from respective dye containing plants has been studied on cotton fabric. A novel and ecofriendly mordanting technique has been devised for creating aluminium-tannate complex on cotton matrix. The new mordanting technique not only involves application of a modified sequence of mordanting chemicals but also employs addition of specific salts in water used in the dyeing process. The dyeing of the mordanted fabric has been carried out under acidic and alkaline conditions at different temperatures. The modified dyeing technique shows an overall improvement of 140-300% in colour strength along with the excellent fastness properties, such as washing, rubbing, perspiration and light. The overall results indicate that all the four natural dyes can be effectively and economically used for dyeing on cotton fabric. The entire chain of collection, extraction and dyeing methodology is environmentally and ecologically compatibl

A new bio-chemical scouring technique for cotton hand processing units

88-92The cotton woven fabric has been subjected to anaerobic treatment using a mixed microflora at room temperature followed by mild alkali boiling. The required enzymes are produced in situ by a mixture of microflora and hence does not need external supply of costly enzymes. The treated fabric is then peroxide bleached, dyed with hot brand reactive dye and evaluated for various parameters. The results show that the properties of treated fabric are at par with the conventionally processed ones. The colour values of the treated and dyed samples are in fact higher than the conventionally processed ones. The above process can be easily coupled to the existing hand processing units. The new process may result in considerable reduction in pollution load along with appreciable saving in energy

Flame resistant cellulosic substrate using banana pseudostem sap

Flame retardancy was imparted in cellulosic cotton textile using banana pseudostem sap (BPS), an eco-friendly natural product. The extracted sap was made alkaline and applied in pre-mordanted bleached and mercerized cotton fabrics. Flame retardant properties of both the control and the treated fabrics were analysed in terms of limiting oxygen index (LOI), horizontal and vertical flammability. Fabrics treated with the non-diluted BPS were found to have good flame retardant property with LOI of 30 compared to the control fabric with LOI of 18, i.e., an increase of 1.6 times. In the vertical flammability test, the BPS treated fabric showed flame for a few seconds and then, got extinguished. In the horizontal flammability test, the treated fabric showed no flame, but was burning only with an afterglow with a propagation rate of 7.5 mm/min, which was almost 10 times lower than that noted with the control fabric. The thermal degradation and the pyrolysis of the fabric samples were studied using a thermogravimetric analysis (TGA), and the chemical composition by FTIR, SEM and EDX, besides the pure BPS being characterized by EDX and mass spectroscopy. The fabric after the treatment was found to produce stable natural khaki colour, and there was no significant degradation in mechanical strengths. Based on the results, the mechanism of imparting flame retardancy to cellulosic textile and the formation of natural colour on it using the proposed BPS treatment have been postulated