AUTEX Research Journal, Vol. 8, No4, December 2007 © AUTEX http://www.autexrj.org/No4-2007/0248.pdf 239 EVALUATION OF THE WEAVABILITY OF SIZED COTTON WARPS Samah MAATOUG 1 , Néji LADHARI and Faouzi SAKLI Textile Research Unit. Ksar Hellal. High Technology Institute, Ksar Hellal Hadj Ali Soua, 5070 Ksar Hellal, Tunisia Phone: + 216 73 475 900, Fax: + 216 73 475 163; 1 E-mail: avnir2004@yahoo.fr Abstract: In weaving, a warp must withstand repeated stretching, caused by shedding and beat-up. It is also subjected to abrasion, which is mainly due to shedding and reed motion. The yarns are therefore sized. Two important reasons for applying sizes to spun warp yarns are to protect them breaking during weaving and to decrease their hairyness so that the tendency for adjacent warp yarns to entangle will be reduced. In this work, we investigated the weaving performance and physical properties of cotton yarn sized at high pressure squeezing. We studied the size penetration, film properties, and the yarn packing density in order to explain the performance of sized yarn. Key words: Cotton yarns, sizing, adherence, cohesion, breaking force, weavability. 1. Introduction As is well known, warp yarns are exposed to various complex stresses during weaving, such as bending forces, dynamic tension of a high periodicity, friction, static electricity, etc. The extent of these stresses varies in accordance with the type of yarn being processed and processing conditions, such as the type of weaving machine, humidity, etc. Moreover, the severity of stresses and subsequent damage to the yarn largely depend on the treatment received during beam preparation [1-6]. Sizing is an established method for improving the weavability of textile yarns. Sizing is the process of coating or impregnating warp yarns with a polymer that improves the efficiency of the weaving operation. In the conventional sizing process, the active agent is applied from a dilute aqueous solution or dispersion, and the yarns are dried to remove the excess water. The drying operation is costly owing to the amount of energy required, and in recent years processes have been developed to reduce the energy costs by minimizing or eliminating the drying phase. Major developments in this area include high pressure squeeze rolling, foam sizing, and hot melt sizing [7-9]. The sizing process provides warp yarns with the necessary strength, elasticity, smoothness, and enables them to acquire resistance to abrasion and static charge. Quality sizing is achieved by deep sizing, where the fibers are fixed in the position in which they were before sizing. Besides deep sizing, it is also important to apply size on the surface to the thread in the form of a film that provides outer protection of the threads [1]. Those in the field of yarn slashing generally agree that sizing agents applied to warp yarns must impart some degree of abrasion resistance. Indeed, many researchers feel that abrasion resistance is the most important property imparted by a size agent. 2. Materials and Methods 2.1. Materials The warp yarns studied were chosen from among cotton yarns (Nm 12.2). Maize starch, polyvinyl alcohol (PVA) and carboxymethyl cellulose (CMC) was provided by the industry. In addition to the sizing agent, the size formulations also contain a plasticizer (glycerol) and lubricant (Avirol). Avirol is a commercial lubricant which is a mixture of fatty acids, fatty alcohols and emulsifiers.