Ayşe Okur

Evaluation of moisture management properties on knitted fabrics

In order to determine the effect of raw material, weave type and tightness on liquid absorption and transmission which is an important factor in the perception of people’s clothing comfort, knitted fabrics made of cotton, viscose and polyester yarns, which had single jersey, 1 × 1 rib and single pique weave type, had three different tightness as tight, medium and loose, were produced. Moisture management tester (MMT) was used for multi-dimensional liquid transport of the fabrics produced. As a result of the study, it is observed that polyester fabrics had higher OMMC values than those of cellulosic-based fabrics. Regarding the effect of tightness, liquid transport has decreased with increasing tightness in general. Weave types examined in this study, were not as strong as raw materials and tightness and did not have such a significant effect.

Objective Evaluation of Fabric Handle by Simple Measurement Methods

In this study, objective and subjective evaluations of fabrics were made to predict fabric handle in a simple way. The aim of this research was to select a suitable form of regression model and predict total handle value with a minimum number of parameters to make a practical approach by using simple laboratory measurements. For this purpose, a wide database of 71 worsted mens suitings was prepared by making subjective and objective evaluations. Subjective tests of primary handle attributes (softness-stiffness, thickness-thinness, and roughness-smoothness) and total handle were evaluated by an expert jury consisting of 18 members, and a subjective total handle value was also calculated using these data. Objective measurements consisted of fabric tensile, bending, shear, compression and surface properties, and pulling through a nozzle tests. A new surface roughness tester was used for measuring surface properties, and it was found that these roughness results might be useful for fabric handle prediction. Linear and log linear regression equations were tested by using 43 parameters. Consequently, some simple regression equations that were practical solutions were obtained to predict fabric handle. A very good result was obtained with a value of the adjusted R2 = 0.88 with eight parameters (LOGP1, LOGB, T42, RΔq1, Rp2, Rq1, Rpmean, P1) from four different property blocks (pulling through a nozzle, bending, tensile, and surface), and in particular, the regression equations reaching an adjusted R2 value over 0.80 are recommended.

The properties of cotton-Tencel and cotton-Promodal blended yarns spun in different spinning systems

In this study, structural, physical and mechanical properties of cotton-Tencel and cotton-Promodal blended ring, compact and vortex spun yarns were compared. Yarn properties such as hairiness, unevenness, imperfections, diameter, density, roughness, roundness, breaking force and elongation were evaluated. In general, hairiness values of ring yarns are the highest and vortex yarns are the lowest. In regard to unevenness, compact yarns have the best and vortex yarns have the worst values. When the effect of spinning systems is evaluated in terms of breaking force and elongation, results show that compact yarns have the highest values whereas vortex yarns have the lowest. In addition, effects of different blend ratios on a yarn’s structural, physical and mechanical properties were examined by using 100% cotton, 100% regenerated cellulosic fibre and 67%—33%, 50%—50%, 33%—67% cotton-regenerated cellulosic fibre blended yarns. In general, an increasing ratio of regenerated cellulosic fibre content in the blend decreases unevenness, imperfections, diameter and roughness values; on the other hand it increases breaking force, elongation, density and shape values. Effect of blend type is also statistically significant for many yarn properties. Mainly, it can be seen that while cotton-Promodal yarns have better physical properties, cotton-Tencel yarns have better mechanical properties.

Predicting the Intra-Yarn Porosity by Image Analysis Method

The flow mechanism that is realized in 3-D depending on the fabric’s porosity structure determines the fabric’s permeability performance. During the flow movement that happens both in the in-plane and through-plane directions, not only the inter-yarn pore properties but inter-fiber pore properties play a significant role as well. The aim of this study is to offer a new method to identify intra-yarn porosity, which has mostly been neglected during the theoretical studies. In this method, initially the cross-sectional images of the cotton yarn in the fabric were achieved, and then the intra-yarn porosity was predicted via image processing and analysis steps. Besides, intra-yarn porosity was calculated theoretically depending on fiber and yarn parameters. The results that were obtained through the image analysis method and theoretical approaches were compared with the experimental data achieved by using Stereo Investigator. As a result, it was observed that the image analysis method was giving fast, objective, successful and expected results while predicting the intra-yarn porosity.

The effect of different knitted fabrics’ structures on the moisture transport properties

In this study, fabrics with different plain, tuck and float stitch combinations in three different tightness levels as tight, medium and loose are produced from combed ring spun cotton yarn. It is aimed at determining the effect of fabric structure on liquid absorption, transport and permeability properties, which are important factors in the people’s perception of wear comfort. The air permeability, wicking ability and moisture management measurements of the produced fabrics are made. It is determined that the increase in the fabric tightness decreases the air permeability and increases the wicking ability especially in 60 min measurements. The fabric tightness has also different effects on different knitting types in terms of moisture management properties. It is observed that structures with float stitches show high wicking ability and moisture management properties in terms of plain, tuck and float stitches combinations.

A new dynamic sweating hotplate system for steady-state and dynamic thermal comfort measurements

This paper discusses design details and measurement principles of a dynamic sweating hotplate system used for both steady-state thermal and water vapor resistance and dynamic water vapor transmission rate measurements. Dynamic and steady-state transfer measurements were carried out by separate systems in preceding studies. Water vapor resistance and dynamic water vapor transmission rate values were determined according to the new principles put forward in this study. Relationships between properties obtained by the new system and standard permeability (water vapor and air) parameters were determined for different types of fabrics used for sports clothing. The materials and physical/constructional properties of the investigated fabrics varied in a wide range as the aim was to determine if the developed system could differentiate their comfort performances. According to the results, water vapor resistance is significantly correlated with fabric weight and water vapor resistance is the best in differentiating the water vapor permeability characteristics of the fabrics among other transfer properties.

A comprehensive study on the general performance properties of Viloft-blended knitted fabrics

Viloft fiber is used frequently in sportswear and underwear in recent years. The purpose of this study is to determine the advantages of Viloft blends used for sportswear, taking into account objective measurements and subjective wear trials. In the study, 1 × 1 rib-knitted fabrics were produced from 20 tex yarn made by blending Viloft fiber and natural, synthetic, or functional fibers. 100% cotton, 100% viscose, and 100% Coolmax, the most preferred fabrics for sportswear were produced as well. Tight-fitting T-shirts with short sleeves and round neck were produced from these fabrics. Physical, mechanical, and transfer properties of the fabrics were measured. Besides, wear trials were conducted with five volunteers using the T-shirts, and mean skin temperature, microclimate relative humidity, and pulse rates were measured. According to the results, the mechanical properties of Viloft-blended fabrics have not been superior than commercial fabrics. Viloft/wool fabrics showing high thermal resistance and water vapor resistance have had poor transfer properties. Viloft/Coolmax fabrics with low water vapor resistance and high moisture management properties have come to the forefront in terms of liquid moisture comfort among Viloft-blended fabrics. It has been observed that knitted fabrics produced by blending Viloft/wool are not preferable options for sportswear. Viloft/Coolmax, Viloft/Thermolite, and Viloft/polyester fabrics have been advantageous for all activity levels.

Variation of the yarn cross-section in fabric

The aim of this study is to investigate the cross-sectional shape and size variation of the yarn in fabric depending on the structural parameters of fabric. For this reason, the dimensions of the yarns that are in the different regions of the weave unit have been determined by achieving the cross-sectional images of the fabrics, which were woven with different weave types and at different weft settings. The variation in the cross-section of the yarn has been evaluated by using the flattening ratio. Consequently, it has been observed that the structural factors which determine the geometry of the fabric, such as weave type and setting, affect the cross-sectional properties of the yarn along the yarn path.

Investigation of pore parameters of woven fabrics by theoretical and image analysis methods

Fluid permeability property is an important performance feature of fabrics and must be considered during the designing processes of products. Since the rate of fluid flow through a textile is a function of viscosity, density, pressure gradient of fluid, and the pore properties of fabric, it is necessary to define pore properties by controlling the structural parameters of fabric for a certain area of use. Due to the complexity of fabric structure, modeling of pore structure and predicting the pore parameters are difficult. In this study, the interyarn porosity, pore size, and pore-size distribution of cotton woven fabrics were calculated by using two-dimensional (2D) and three-dimensional (3D) geometrical pore models and image analysis method. The effect of weave types and weft settings on the pore parameters and air permeability of fabrics were investigated, and the advantages of 2D, 3D geometrical pore models and image analysis method were compared.

Prediction of the in-plane and through-plane fluid flow behavior of woven fabrics

The permeability property of fabric is a desired performance property of textile structure used in different areas. In this study, the relationship between in-plane and through-plane permeability behaviors and the structural properties of woven fabrics having numerous usage areas, such as clothing and technical textiles, were investigated with the help of data obtained from a group of test fabrics having different weave types and weft settings, which were produced by using the same warp and weft linear density. In the study, the pore properties were examined in two regions: inter-yarn and inter-fiber pore regions. After defining the pore properties, which were determined by the structural and geometrical properties of fabric according to different approaches, the permeability results of both in-plane and through-plane directions were predicted theoretically by using obtained pore properties in flow equations. Estimated permeability results were compared with experimental results and the suitability of methods were discussed.