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Linen fabrics were cationized using 3-chloro-2-hydroxypropyl trimethyl ammonium chloride in alkaline medium. The cationized linen fabrics were dyed independently, with different dyestuffs, namely reactive, direct and acid dyes in absence of salt (no-salt dyed). Factors affecting the nosalt dyeing process of cationized linen fabrics were investigated. These factors included dye concentration, pH of the dyeing bath, dyeing temperature and time as well as the chemical nature of the dyes used. The dyed samples were monitored for color strength (K/S) after soaping and after DMF extraction as well as fastness properties. It was found that for all dyestuffs used, the magnitude of K/S of the dyed samples depends on the nature of the dyes and the conditions used in each case. It was also seen that for no-salt dyeing of cationized linen fabrics, the maximum K/S was achieved at dye shade 2.5 % (ows) and dye bath’s pH 7-9, at 60°C for 20 minutes. In addition to this, the color strength was much higher in case of cationized and no-salt dyed samples compared with the uncationized and traditionally salt-dyed linen fabrics; meanwhile, the overall fastness properties were comparable. Microscopic examination of the cationized and no-salt dyed linen fabrics showed an excellent dye penetration and no evidence for the ring dye phenomena was observed.

Fibre reactive dyes are very popular for cellulosic garments as they are environmentally safe and having good overall fastness properties. But application of these dyes requires a very high concentration of salt. The salt released from garment dyeing increases salinity in drain water stream which has a negative impact on environmental ecology. The present work aims to eliminate the usage of salt during dyeing of cotton goods with reactive dyes.

The methodology adopted here, for the elimination of salt in cotton dyeing, was based on the principle of cationisation (to develop a positive charge) of cotton. The same was achieved by subjecting the caustic pretreated cotton fabric samples to a treatment of 1, 2 dichloroethane followed by methylamine to introduce amino groups in the cellulose structure. The treated cotton when dyed from slightly acidic bath generates positive sites due to protonation in the amino group. The reactive dyes being anionic (negatively charged) in solution get attracted to the positive charges on the fibre which eliminates the salt requirements for satisfactory dye exhaustion.

The investigation was conducted for cold brand, hot brand and highly exhaustive reactive dyes. The modified cotton showed excellent dye exhaustion for all the dyes in the absence of salt. The treatment was found to improve the dye fixation also. The modification was assessed through elemental analysis.

This study may be further extended to viscose material after suitably modifying the treatment conditions.

A pretreatment to cotton which could eliminate the usage of salt in its dyeing with reactive dyes is revealed.

The study explored a newer technique of cotton dyeing without salt usage. Both garment dyeing units and fabric/yarn finishing industries would thus be helpful.

Mill scoured and bleached linen fabrics were cationized using Quat-188. Cationization was carried out as per the exhaustion or the cold pad-batch technique under a variety of conditions. Factors affecting the cationization reaction of linen fabric were studied. These factors include Quat-188 concentration, NaOH concentration (or pH of the reaction medium in case of exhaustion method), reaction time and temperature as well as material to liquor ratio (in case of exhaustion method). The cationized samples were monitored for nitrogen content, and the reaction efficiency calculated thereof, as well as for K/S of the no-salt dyed samples. Results obtained indicate that the efficiency of cationization of linen fabric with Quat-188 depends on the type of application technique and the conditions used in each technique. Using the exhaustion technique, maximum reaction efficiency between Quat-188 and linen fabric was achieved at Quat-188, 80 g/1 and pH, 13 and 70°C for 60 minutes using material to liquor ratio, 1:20. Lower material to liquor ratio was not practically possible. The results also depict that any deviation from these conditions, for example, higher pH, temperature or material to liquor ratio, leads to an increase in the hydrolysis of Quat-188 molecules and hence, lower reaction efficiency. With the cold pad-batch technique, maximum reaction efficiency was achieved when the linen fabric was padded in a solution containing NaOH, 50 g/1 and Quat-188, 125 g/1, then squeezed to a wet pickup of 100% and batched for 15 hours. Results obtained also signify that both dry and wet wrinkle recovery angles increase as the degree of cationization (expressed as N % of cationized linen fabric) increases. Moreover, the tensile strength of cationized linen fabric is higher than that of uncationized linen and such an increase depends on the degree of cationization.

The purpose of this paper is to extract the eco-friendly natural dye obtained from the flower of Spathodea campanulata and apply on silk fabric using combination of mordants. The fastness properties of the flower of Spathodea campanulata dyed silk fabric have been studied using different combination (1:3, 1:1 and 3:1) of various mordants, such as myrobolan: nickel sulphate, myrobolan: aluminium sulphate, myrobolan: potassium dichromate, myrobolan: ferrous sulphate and myrobolan: stannous chloride. The wash, rub, light and perspiration fastness of the dyed samples have been evaluated.

For dyeing there are three methods are used. They are Pre mordanting, Simultaneous mordanting and Post mordanting methods. Dyed silk materials are tested by using wash fastness, rub fastness, light and perspiration fastness methods.

It is found that Spathodea campanulata dye can be successfully used for the dyeing of silk to obtain a wide range colours by using various combinations of mordants. With regards to colour fastness, test samples exhibit excellent fastness to washing, rubbing, except for pre-mordanting using myrobolan: potassium dichromate combination; and good to excellent fastness to perspiration in both acidic and alkaline media.

Availability of literature related to this work is not available. The study of combination of mordants of this natural dye on silk is a new research work and the large scale preparation is definitely very useful to the society.