Investigation of porosity and air permeability values of plain knitted fabrics

The air permeability of a fabric is defined as the amount of air passed over a surface under a certain pressure difference in a unit time. This value has significance with respect to the usage area. Since knitted fabrics have a loop structure, they have more pores than woven fabrics; therefore, in general, the air permeability of knitted fabrics is higher than that of woven fabrics of the same weight. An experiment to determine the air permeability is very important as it defines the properties of keeping warm, protection against the wind, breathability etc. of knitted fabrics used as clothing. In this study, it has been attempted to establish a theoretical model for the porosity and predicted air permeability of plain knitted fabrics. A theoretical model was created to predict the porosity and air permeability of a knitted structure depending on the geometrical parameters, such as the courses per cm, wales per cm, stitch length, fabric thickness, yarn count, diameter of yarn and fiber density. For this purpose, a theoretical model of porous systems based on D'Arcy's law was used, the validity of which was confirmed by experimental results using 100% cotton plain knitted fabrics produced from ring and compact yarns of different yarn number linear density and tightness

Investigation of air permeability of single jersey fabrics with different relaxation states

In this work, single jersey fabrics were produced with different yarn numbers and loop lengths by means of conventional ring-spun and compact ring yarns. Knitted fabrics were subjected to two different relaxation treatments, dry and washing. After relaxation, air permeability of cotton-knitted fabrics with different yarn numbers and loop lengths were determined. In addition, wales per centimeter, courses per centimeter, thickness, and weight of fabric were tested. According to the test results, relaxation type and some fabric structural parameters affected air permeability of single jersey fabrics. Following the washing relaxation, it was found that knitted fabrics became tighter, their weight and thickness were higher, while their air permeability was lower. © 2011 The Textile Institute

Investigation of effects of repeated laundering on the knitted fabrics with biopolishing treatment [Biyoparlatma uygulanmiş örme kumaşlara tekrarli (çoklu) yikamalarin etkisinin incelenmesi]

The purpose of this research was to investigate the effects of repeated laundering on the knitted fabrics with biopolishing treatment. The fabric samples were subjected to laundering process in a domestic washing machine following 10 and 20 times. With respect to the experimental results, maximal dimensional variations were determined after ten laundering cycles. Increasing laundering cycles decreased the fabric bursting strength and pilling values, but increased some deformations on fabrics surface

Taguchi approach for the optimisation of the bursting strength of knitted fabrics

In this paper, the bursting strength of knitted fabrics was optimised using the Taguchi experiment design technique, which is a recently famous approach. In the evaluations, analyses of variance (ANOVA) and the signal to noise ratio were used. 9 experiments were performed with respect to the L9 orthogonal design for the Taguchi approach. The results show a considerable improvement in the S/N ratio as compared to the initial condition. With the Taguchi processes, we can easily determine optimum conditions for maximising the bursting strength of knitted fabrics with simple experiments

The use of the taguchi design of experiment method in optimizing spirality angle of single jersey fabrics

In this paper, spirality angle of single jersey fabrics was optimized using the Taguchi experiment design technique, which is a recently famous approach. In the evaluations, analysis of variance (ANOVA) and signal to noise ratio (S/N) were used. Nine fabric configurations with respect to L9 orthogonal design for Taguchi approach were knitted and tested. Relaxation treatment, yarn type and loop length, effecting on spirality angle were selected as control factors. Based on the S/N ratio and ANOVA analyses, the optimum levels of these parameters obtained in this paper, relaxation type of dry relaxation, yarn type of open end yarn, loop length of 0,25 cm. By using the Taguchi experimental design approach, low number of experiments can be performed to achieve the combination providing the best performance. Thus, before starting manufacturing in factory, it can be easily predict the spirality angle of single jersey fabrics using the defined factors