The Use of Poly(amidoamine) Dendrimer in Modification of Jute for Improving Dyeing Properties of Reactive Dyes Ali Akbar Zolriasatein, 1 Mohammad Esmail Yazdanshenas, 2 Ramin Khajavi, 3 Abosaeed Rashidi, 4 Farhood Najafi 5 1 Department of Textile Engineering, Shahr-E-Ray Branch, Islamic Azad University, Tehran, Iran 2 Department of Textile Engineering, Yazd Branch, Islamic Azad University, Yazd, Iran 3 Department of Textile Engineering, South Tehran Branch, Islamic Azad University, Tehran, Iran 4 Department of Textile Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran 5 Department of Resin and Additives, Institute for Color Science and Technology, Tehran, Iran Correspondence to: A. A. Zolriasatein (E-mail: zolriasatein@iausr.ac.ir) ABSTRACT: In this study, the poly(amidoamine) (PAMAM) G-2 dendrimer was applied to the jute yarn. Fourier transform infrared spectrophotometry (FTIR) of the dendrimer-treated jute yarn indicated that all carbonyl groups of the jute fiber have reacted with amino groups of the PAMAM dendrimer. Jute yarns which had been pretreated with PAMAM dendrimer displayed markedly enhanced color strength with reactive dyes, even when dyeing had been carried out in the absence of electrolyte or alkali. Dendrimer- treated jute yarn showed much better light-fastness than that of untreated jute yarn. V C 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 000: 000–000, 2012 KEYWORDS: dendrimers; polyamidoamine; jute; dyeing; reactive dyes Received 21 November 2011; accepted 7 March 2012; published online DOI: 10.1002/app.37666 INTRODUCTION Coloration of jute fabric has become essential for all sorts of fabric starting from decorative value added fabrics to attractive packaging material. Due to the eco-friendly and biodegradable nature of jute fiber, the demand for jute fabric is rising world- wide day by day. One of the major problems that restricts the application of jute products is that jute suffers seriously from light-induced discoloration (i.e., due to phenolic structure of lignin). 1,2 In case of reactive dyes, the dyes reacts with hydroxyl group of the fiber by either substitution or addition reaction. 3 For their reaction with cellulosic fibers, reactive dyes typically rely on an elevated pH (commonly over 10.5) and large amounts of elec- trolyte (NaCl or Na 2 SO 4 ) to overcome the static repulsion between cotton fibers and reactive dyes in order to promote dyeability. During their application, along with dye absorp- tion, dye hydrolysis also takes place. The greatest problem is dye hydrolysis or the reaction of dyes with water, since hy- drolysis blocks the reactive sites so that the dyes cannot form covalent bond with fibers. The hydrolyzed dye retained on the fabric and is removed by severe washing. This results in wastage of dye. Hydrolysis of the dye by water is more rapid at higher pH values. The application of reactive dyes to cellu- losic fibers continues to be costly for the dye house in terms of dye wasted, electrolyte, and alkali used and, in addition, presents a large pollution load for the environment. 4 An alternative approach to increase dye uptake and dye fixation is by the modification of cellulosic fibers themselves. In essence, attention has focused on the introduction of cationic groups by means of pretreatment, commonly via quaternized amino groups, to which the anionic reactive dyes are attracted and so enhance dye-fiber substantivity. Such enhanced dye-fiber sub- stantivity can result in reduced electrolyte usage and, poten- tially at least, lead to salt-free dyeings. In addition, if the cati- onic pretreatment compound also contained nucleophilic groups, such as primary amine or thiol, it is possible that the reactive dye could react with such added nucleophiles at lower pH values than are normally needed for cellulosic fiber dyeing; this, in turn, could, theoretically, lead to reduced dye hydrolysis. Dendritic polymers can be divided into two classes: den- drimers (branched uniform structure) and hyperbranched V C 2012 Wiley Periodicals, Inc. WWW.MATERIALSVIEWS.COM WILEYONLINELIBRARY.COM/APP J. APPL. POLYM. SCI. 2012, DOI: 10.1002/APP.37666 1