Crosslinking of partially carboxymethylated cotton fabric via cationization Mohamed Hashem ) , Rakia Refaie, Ali Hebeish Textile Division, National Research Centre, Dokki, Cairo, Egypt Received 13 May 2003; accepted 7 May 2004 Abstract A novel method for non-formaldehyde easy care finishing of cotton fabric based on ionic crosslinking has been examined. Accordingly, the cotton fabric was first partially carboxymethylated to impart to it the anionic character through its reaction with monochloroacetic acid in alkaline medium. Application of reactive cationic agent in alkaline medium affects crosslinking of the resulting anionic cotton in a second step. The reactive cationic agent used was 3-chloro-2-hydroxypropyl trimethyl ammonium chloride (Quat-188). Factors affecting the quaternization reaction of partially carboxymethylated cotton fabric (PCMC) have been studied. These factors include NaOH concentration, reaction time and temperature, quaternizing agent concentration as well as material to liquor ratio and method used for quaternization. The latter includes two methods, namely, the exhaustion method and the cold pad- batch method. Correlations between the degree of crosslinking (expressed as nitrogen and carboxyl content) of quaternized PCMC fabric and the easy care properties were also made. Easy care properties include wet and dry crease recovery angles as well as tensile strength and elongation at break. Results obtained signify that: (a) optimum conditions for cationization of PCMC fabric are obtained when the Quat-188/sodium hydroxide molar ratio is 1/2 using the cold pad-batch method for 24 h; (b) the extent of cationization reaction, expressed as percent nitrogen, increases as the carboxyl content of the PCMC fabric increases, and (c) both wet and dry crease recovery angles of PCMC samples exhibit much higher values compared with that of untreated samples while both tensile strength and elongation at break display marginal improvements. These improvements depend mainly on the degree of ionic crosslinking. Ó 2004 Elsevier Ltd. All rights reserved. Keywords: Carboxymethylation; Cationization; Cotton; Finishing; Ionic crosslinking; Textile 1. Introduction The driving force behind the chemical finishing of cotton during the next 10 years is anticipated to com- prise several factors. Of these factors, mention is made of the following: (i) chemical finishes which maximize the added value; (ii) chemical finishes which are friendly with the environment; (iii) methods which are conve- nient for application, and (iv) the need for better quality and minimum use of water and energy. Since the late 1980s there has been a steady increase in the demand for easy care, wrinkle resistant (durable press) 100% cotton apparel. Formaldehyde-based chem- ical finishes such as dimethylol dihydroxyethylene urea and its etherified derivative with lower formaldehyde concentrations are used to impart ease of care character- istics and durable press properties to cotton apparel. They are cost effective and efficient [1e5]. However, the free formaldehyde on the finished fabric is considered one of the major problems in easy care and durable press of cotton finishing. This is understandable given that the adverse effects of this formaldehyde range from strong irritant to cancer. In addition, washing the apparel pollutes the washing liquor. By virtue of its carcinogenic effect, the allowable formaldehyde in air should not exceed 0.1 ppm in the work place and worker health must be monitored in the textile industry when it is used. This is strictly stated in recent actions by federal regulatory agencies in most industrialized countries and in some othersda point which has renewed interest in non- formaldehyde textile finishing substances for work with cotton based textiles [6,7]. Furthermore, formaldehyde- based finishing is very energy-consuming since the curing ) Corresponding author. Tel.: C20-2337-0931; fax: C20-2337-1635. E-mail address: mhashem22@hotmail.com (M. Hashem). Journal of Cleaner Production 13 (2005) 947e954 www.elsevier.com/locate/jclepro 0959-6526/$ - see front matter Ó 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.jclepro.2004.05.002