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1.0 Introduction: Reactive dyes are extensively used for dyeing and printing cellulosic materials and blends containing cellulosic portion. [1] This is the reason behind the fact that researches on synthesis and development of reactive dyes,[2] improvement of their application possibilities and procedures has been practicing mostly by dyers, chemist & engineers.[3] It has also been found that the dyeing properties of reactive dyes much depend on the structure of reactive dyes. Here the dyeing properties mean the applicability, technology, permanency etc. [2] and structure of reactive dyes is its molecular structure.[4] Method of application and permanency of dyeing is much dependent on the composition of reactive dyes -more directly we can say that on the functional group attached with the reactive dyes. Several reactive dye functional groups have been synthesized, their chemistry has been understood and behavior on application and permanency on the substrate has been discussed in terms of exhaustion and fixation. [5] These two properties in case of reactive dyeing define the suitability, compatibility, permanence, economy etc. of dyeing. [1] [6-8] The functional or reactive group or groups attached with the reactive dye molecule have direct effect on the exhaustion and fixation of dyes with the cellulosic substances. [5, 9, 10]The other chemicals and dye bath conditions used in the dyeing process also have their effect in exhaustion and fixation, but these are not properties of dyestuffs or only assist to improve exhaustion and fixation. 1.1 Silk: Silk is the royal fibre and its coloration is also an art. There are wide ranges of dyestuff accessible for silk dyeing. [11, 12] Nearly every type of dyestuff used for cotton and/or wool can be used for dyeing silk. |
