S.F.Ibrahim et al./ Elixir Appl. Chem. 39C (2011) 5008-5014 5008 Introduction Research on textile fibres is now increasingly being concentrated mainly on developing modified fibres having better properties than unmodified fibers (1-3) .There are now –a-days numerous possibilities for modifying cotton fibers in order to improve their dyeing performance with different dye classes (4) . Where, Native cellulose consists of linear macromolecules formed by a hydroglucose units linked together by glucosidic bonds. Cellulose chains in the solid state are able to form intra and inter-molecular hydrogen bonds, leading to an organized chain structure (5) . Thus a native cellulosic fiber, such as cotton, can be regarded as a highly crystalline fiber, in which amorphous regions are formed by the most extended chains. Dye molecules cannot penetrate the highly ordered crystalline regions of native cellulose and their adsorption can only take place in the amorphous regions, which are highly ordered as well. (6,7) . chemical composition of fibers determines, to some extent, the type of best dye to be applied. Several types of dye- fiber interactions are reported in the literature, which involve; electrostatic, van der Waals bonding and hydrophobic interactions. As the primary hydroxyles of cellulose elementary units are responsible for the solubility and dye-ability of cellulosic materials, the formation of dye-fiber hydrogen bonds is controlled by the presence of hydrogen bonding functional groups in the fiber and the dye. Chitosan(figure1) is a renewable biomaterial, highly viscous, chitosan, poly (1, 4) –2- amino-2 deoxy- B-D-glucose) (8) . The degree of deacetylation (DD) and molecular weight of chitosan have the greatest influence on its physical and chemical properties, including emulsification capacity, aggregation activity, rheological and physicochemical properties (9) .Due to the characteristic properties of chitosan such as nontoxicity, ecofriendly, biodegredability ,bioactivity and water binding capacity, chitosan and its modified analogs have found many applications in pharmacetical and medical applications, textile dyeing and finishing. Figure (1) : Chemical structure of chitosan In our present paper, we have investigated the characterization of the dyeing performance of cotton fabrics after their finishing with finishing bath formulation containing emulsion lattices based on acrylate monomers, chitosan and polyethylene glycol (PEG) with improvement of dyeing properties with acid , and reactive, dyes in terms of dye-uptake, percentage dye fixation, colour parameters; (L*,a*,b* and colour difference) and estimated light fastness grades with different concentration of chitosan. Experimental work Materials and chemicals: Cotton fabric of 150g/m 2 treated with a solution containing 0.5g/l Egyptol non ionic detergent and 0.5g/l Na 2 CO 3 at a temperature of 70 o C for 1 h, thoroughly washed and air dried at room temperature. Tele: E-mail addresses: drsaherfawzy09@hotmail.com © 2011 Elixir All rights reserved Characterization of dyeing performance for finished cotton fabrics using different dyes S.F.Ibrahim, D.M.Essa and S.H.Samaha National Institute of standards (NIS), Textile Metrology Lab. ABSTRACT The present investigation aims to study and characterize the dyeing performance of cotton fabrics finished with finishing bath formulation containing emulsion lattices based on acrylate monomers, chitosan and polyethylene glycol (PEG) with improvement of dyeing properties with acid and reactive dyes. The finished cotton samples are examined and evaluated through measuring nitrogen content and the Fourier transform infrared spectra (FTIR). Evidences of finishing were obtained by IR from the appearance of CO bands absorbance and the reducing of relative intensity of OH, with respect to cotton. The dyeing performance of the finished cotton fabrics including testing of ; dye-ability(k/s), percentage dye fixation, colour parameters(L*,a*,b* and colour difference(∆E) and estimated light fastness grades with respect to the different used chitosan concentration in the finishing bath formulation. The work involved also studying the effect of different dyeing times on all of the last stated parameters. The obtained results showed that dye-uptake increased by increasing chitosan concentration in the finishing bath , the applied reactive dye showed the highest percentage increase in both dye-ability and percentage dye fixation .In addition the estimated light fastness reating values of all of the examined fabrics where these rating grade values increased by increasing both chitosan concentration in the finishing agent and dyeing time .In addition , the applied acid dye recorded the highest light fastness values reaching (4- 5) for (3.0g/l) chitosan after one hour dyeing compared to a rating value of (3)for blank fabrics assessed on standard gray scale. © 2011 Elixir All rights reserved. ARTICLE INFO Article history: Received: 27 August 2011; Received in revised form: 22 September 2011; Accepted: 30 September 2011; Keywords Cotton fabrics, Finishing agent, Chitosan, Acrylate monomers, Dye, ability, Reactive dye, Acid dye, Optical density, Colour parameters. Elixir Appl. Chem. 39C (2011) 5008-5014 Applied Chemistry Available online at www.elixirpublishers.com (Elixir International Journal)