Indian Journal of Fibre & Textile Research Vol. 36, September 2011, pp. 259-265 Accessibility of mercerized, bioscoured and dried cotton yarns Igor Jordanov a & Biljana Mangovska Faculty of Technology and Metallurgy, Ss. Cyril & Methodius University, R. Boskovic 16, 1000 Skopje, Macedonia Received 29 January 2010; revised received and accepted 29 October 2010 The structure of cotton yarns mercerized, bioscoured using acid and alkaline pectinases and dried at different temperatures has been studied using X-ray diffraction and infrared spectroscopy. The accessibility is investigated in terms of monolayer capacity, moisture regain, water retention values, and diffusion coefficient of the Congo Red dye. It is observed that the drying at 80 o C does not change the crystallinity, but type of scouring changes the cotton accessibility towards water and dyes. The temperature of the drying and type of scouring show significant influence on the monolayer capacity, moisture regain and water retention values. Keywords: Bioscouring, Cotton, Mercerization, Monolayer capacity, Moisture regain, Pectinases, Scouring, Water retention 1 Introduction The pore volume and surface area of cotton fibre play important role in determining the accessibility, sorption rates and uniformity of reactions involved in dyeing and finishing processes. The pores are interspersed with microfibrillar structure of celluloses and affect the reactivity of celluloses, since they control the accessibility of reagent to the internal sites at which either chemical reaction or physical adsorption by secondary valence forces can occur 1 . The size of pores is easily affected by intracrystalline swelling agents, like strong NaOH solutions used during mercerization. The extent of changes occurred depends on the processing time, caustic concentration, temperature, degree of polymerization, source of cellulose, slack or tension treatment, degree of applied tension during the treatment and physical state of cellulose 2-6 . The temperature of drying after mercerizing also influences the pores size. Samples mercerized and directly dyed adsorb more water and dye than those dried before dyeing 1, 7, 8 . Higher temperature of drying decreases the size of the pores consequently as well as the dye content and the water absorption 2 . Mercerization partially removes the non-cellulosic components 9 . The accessibility of mercerized cotton can be improved by caustic scouring in the presence of chelating agents and surfactants 10 . Mercerized- scoured cotton has almost completely removed non- cellulosic components, thus increasing accessibility towards dyes and different reagents 11, 12 . Attempts have been made to replace conventional alkaline scouring with milder enzymatic scouring processes using different enzymes, such as cellulases, pectinases, lipases, proteases, and their mixtures, surfactants, and treatment parameters. Pectinases appear to be the most suitable for this purpose 13-24 . Properly selected nonionic surfactants and mechanical agitation are also very important for sufficient scouring 13 . In earlier studies 18-24 , optimal parameters for alkaline pectinase and acid pectinase scouring treatments have been determined. Alkaline and acid pectinase scouring treatments were performed on mercerized cotton yarns and the cotton cuticle composition was studied after different scouring treatments 9 . In the present study, an attempt has been made to modify the pores structure with mercerizing, scouring using acid and alkaline pectinases and applying different temperatures of drying. 2 Materials and Methods 2.1 Materials Plied ring-worsted cotton yarn with a linear density of 30×2 tex and spun with 330 twists/m was used. _____________ a To whom all the correspondence should be addressed. E-mail: jordanov@tmf.ukim.edu.mk