Faculty of Management and Information Sciences

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Browsing Faculty of Management and Information Sciences by Author "Shahnaz Parveen Khattak"

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    APPRAISAL OF FASTNESS AND TENSILE PROPERTIES OF COTTON FABRIC DYED WITH NATURAL COLOURANTS BY PAD-STEAM METHOD
    (College of Home Economics, University Of Peshawar., 2015) Shahnaz Parveen Khattak; Supervisor Prof. Dr. Bashir Ahmad
    This study was conducted to appraise the fastness properties of some natural dyes of plant origin on cotton fabric. Owing to the growing trend of going “green” throughout the world, a renewed international interest has developed in the dyeing of textiles with natural colourants. These dyes exhibit better biodegradability and are usually well compatible with the environment. They contain natural colouring matter which is generally non-allergic, non-toxic, non-carcinogenic and non-hazardous to the user and environment. Common drawbacks of natural dyes are their non-uniform shades and poor to moderate colourfastness. In this research project, solvent extracted dyes from alkanet (Alkana tinctoria), cutch (Acacia catechu), madder (Rubia tinctorum) and ready to use dyes from marigold flower (Tegetes erecta L) and Turkey red (Rubia cordifolia) have been applied on cotton fabric through pad-steam dyeing procedure. To evaluate the possibility of increasing their colour fastness, various dyeing auxiliaries (mordants, UV absorbers, cationizing agents, crosslinkers, etc.) have been applied by pre-treatment and post-treatment techniques. Metallic mordants included aluminium sulphate, copper sulphate, ferric chloride, potassium dichromate and hydrated potassium aluminium sulphate or alum. Better fastness (wash, light, crocking), colour coordinates (lightness, chroma, hue and colour strength) as well as improvement in tensile strength was achieved with postmordanting of copper sulphate on most of these dyes. Pre-mordanting of potassium dichromate brutally damaged the tensile strength of the alkanet dyed sample. Cationization of cotton with quaternary ammonium compound (Albafix WFF) has improved the fastness properties, tensile strength as well as relative colour strength (K/S) of cotton dyed with alkanet, cutch and marigold flower dyes. Post-padding of reactive UV absorber based on oxalanilide (UV-SUN) and UV absorber Rayosan C (heterocyclic compound) greatly increased the light fastness of cotton fabric, dyed with these dyes. Similarly, post-treatment of soft polyurethane emulsion (Dicrylan) has enhanced the light and wash fastness as well as retained the tensile strength of natural dyed cotton. The use of crosslinkers could not bring further enhancement in the K/S value of cotton dyed with alkanet and generally, they yielded lighter shad