a SciTechnol journal Research Article Hasani, et al., J Fashion Technol Textile Eng 2014, 2:1 http://dx.doi.org/10.4172/2329-9568.1000107 Journal of Fashion Technology & Textile Engineering All articles published in Journal of Fashion Technology & Textile Engineering are the property of SciTechnol, and is protected by copyright laws. Copyright © 2014, SciTechnol, All Rights Reserved. International Publisher of Science, Technology and Medicine An Investigation into the Effect of Fabric Structure and Yarn Twist Direction on the Curling Behavior of Single Jersey Weft Knitted Fabrics Hossein Hasani 1 *, Saeed Ajeli 1 , Parvaneh Kheirkhah 1 , and Azam Pasandidehpour 1 Abstract In this work, the curling behavior of single jersey weft-knitted fabrics produced from different structures and yarn twist directions is studied. Curling behavior was characterized in terms of curling surface in both course and wale directions. It is concluded that the curling surface value of weft-knitted fabric samples produced from the Z-twist ring-spun yarn is higher than that of the samples produced from the S-twist cotton ring-spun yarn. The comparison between different fabric structures reveals that the presence of tuck stitches in fabric structure results in a (or leads to a) lower curling surface. During the tuck loop formation, the higher yarn tension on the held loop causes them to rob yarn from adjacent knitted loops. This in turn exposes more moment though the loop and the higher curling would be expected. But the results show that the friction between the yarns in contact points has a signifcant effect on curling reduction. It has been fgured out that the structures comprised of tuck and knit loops present lower curling phenomenon. In this study, double cross tuck and triple cross miss structures show the lower and higher curling surface values. Totally it could be stated that the structures possess miss loops have the lower curling surface in the wale direction while it is the opposite in the course direction. For structures including tuck loops, the results are quite in contrary. Keywords Single jersey weft-knitted fabric; Curling surface; Yarn twist direction, Fabric structure Introduction A wide variety of knitted fabrics are commonly comprised of the single jersey-knit construction, ranging from sheer, lightweight hosiery to thick, bulky sweaters. Tese fabrics are of unbalanced structures which have a tendency to curl at the edges. Tis condition can frequently be corrected during the fabric fnishing process. If not corrected, this problem can be quite troublesome in cutting and sewing processes [1]. In general, knitted fabrics have a three-dimensional structure. At the point where the new needle loop is drawn through the old loop, *Corresponding author: Dr. Hossein Hasani, Department of Textile Engineering, Isfahan University of Technology, Isfahan 8415683111, Iran, Tel: +98-311-391- 5040; Fax: +98-311-391-2444; E-mail: h_hasani@cc.iut.ac.ir Received: January 31, 2014 Accepted: March 21, 2014 Published: March 25, 2014 the structure is composed of two yarn thicknesses. During the loop formation, the needle loop is held down through both its head and feet, by the other loops in the same wale, but its side-limbs tend to curve upwards. When the fabric is cut, the loops are no longer held in this confguration; so that the fabric curling along the wale and course direction respectively occurs towards the fabrics technical face and technical back. Doyle [2] described the curling behavior of plain-knitted fabrics and studied the efect of yarn elasticity, fexural rigidity and torsion rigidity on this phenomenon. Hamilton and Postel [3] analyzed the curling behavior of un-relaxed wef-knitted fabrics in terms of curling couple about the course and wale directions using a pure bending tester. Bühler et al. [4] developed a test method to measure the selvedge curling of plain-knitted fabric. Besides, they studied the efects of fber type, yarn dying process, tightness factor, relaxation process, and condition and time of stocking on curling behavior of wef-knitted fabrics. Phukan and Subramaniam [5,6] investigated the efect of treatment on curling and proposed some methods to reduce it. Ucar [7,8] used a multiple regression analysis to predict the curling distance of dry-relaxed cotton plain-knitted fabric based on mechanical parameters such as bending moment and fexural rigidity. Kurbak and Ekmen [9] also presented a new geometrical model for widthwise curling of plain-knitted fabrics. Basiri et al. [1] investigated the curling behavior of cotton dry-relaxed single jersey wef-knitted fabric using a new non-destructive test method in which the curling behavior could be characterized in terms of de-curling force at the peak point, and total de-curling energy. Minapoor et al. [10] investigated the efect of fber, yarn, and fabric parameters on curling phenomenon of single jersey wef- knitted fabrics which is interpreted to have curling surface in both course and wale directions. Trough their researches, the curling behavior of fabric samples was predicted using artifcial neural network in which the scale of conjugate gradient learning algorithm based on the selected process parameters was determined. In this paper, the efects of the tuck and miss stitches and also yarn twist direction on the curling of single jersey knitted fabrics in terms of curling surface about the course and wale directions have been investigated. Experimental Samples preparation In this research, two groups of fabric samples were produced in order to investigate the efects of yarn twist direction and the fabric structures individually on the curling phenomenon of single jersey knitted fabrics. In this work, plain wef-knitted samples produced from cotton/ polyester blended yarns have been employed for investigating the curling behavior afected by varying the yarn twist direction. Te 70/30 blending ratio of cotton/polyester slivers (Ne sliver =0.91) was utilized and the 27Ne spun yarns with two diferent twist directions (Z and S) were spun using a conventional ring spinning machine