Shrinkage Of Yarns Research Articles

Enhanced Hydro-Actuation and Capacitance of Electrochemically Inner-Bundle-Activated Carbon Nanotube Yarns.

Recently, several attempts have been made to activate or functionalize macroscopic carbon nanotube (CNT) yarns to enhance their innate abilities. However, a more homogeneous and holistic activation approach that reflects the individual nanotubes constituting the yarns is crucial. Herein, a facile strategy is reported to maximize the intrinsic properties of CNTs assembled in yarns through an electrochemical inner-bundle activation (EIBA) process. The as-prepared neat CNT yarns are two-end tethered and subjected to an electrochemical voltage (vs Ag/AgCl) in aqueous electrolyte systems. Massive electrolyte infiltration during the EIBA causes swelling of the CNT interlayers owing to the tethering and subsequent yarn shrinkage after drying, suggesting activation of the entire yarn. The EIBA-treated CNT yarns functionalized with oxygen-containing groups exhibit enhanced wettability without significant loss of their physical properties. The EIBA effect of the CNTs is experimentally demonstrated by hydration-driven torsional actuation (∼986 revolutions/m) and a drastic capacitance improvement (approximately 25-fold).

Prediction of Polypropylene Yarn Shrinkage in the Heat-Setting Process Using the Fuzzy Inference System

In the carpet industry, yarn shrinkage is a very important specification, the percent of shrinkage affected by heat setting parameters, time and temperature. In order to obtain the best uniform appearance of carpets, the shrinkage of pile yarns should be minimum in the carpet sizing process. An inappropriate heat set yarn may cause an undesirable shrinkage result and uneven pile height on carpets after the sizing process. It could be useful for manufacturers to understand the optimum condition of heat setting to obtain the low shrinkage of heat set yarns before weaving. Therefore, a fuzzy logic model is designed to predict the shrinkage percentage of polypropylene yarn in different heat setting conditions. Time and temperature are taken into account as input variables and yarn shrinkage is predicted as output. For validation of the model, the yarn samples heat set under various sets of time and temperature and finally yarn shrinkages have been measured experimentally. The result of the fuzzy model prediction compared to regression results and signify the fuzzy results present good and better match with experimental results with the acceptable R2=0.97 and average error (2.59%).

3D network structure and sensing performance of woven fabric as promising flexible strain sensor

A flexible strain sensor was developed through weaving conductive yarns to 3D woven fabric. The relationship between the sensing performance of the woven fabric and its 3D network structure containing yarn shrinkage and arrangement density, as well as fabric interweaving, was investigated according to Pierce’s fabric geometry model and the assumption of elastic strain of yarn. Based on such models and assumption, the theoretical results were verified by the experimental data from uniaxial stretching, and the trends of both results were consistent. The sensitivity of woven fabric on its elastic strain is relatively small (GF < 2) and nonlinearity. With the deformation of fabric geometry structure (Stage I) caused by stretching on warp direction, the shrinkage of weft yarn (cw) and interweaving points (nw) decreased or the arrangement density of warp yarn (Nj) increased, resulting in improved sensitivity on warp direction. At yarn deformation stage (Stage II), the increase in interweaving points (nw) or the decrease in arrangement density of warp yarn (Nj) could improve the sensitivity on warp direction. All the results provide a theory basis for the design and development of flexible strain sensor with promising application as wearable electronic device.

Engineering Design and Mechanical Property Characterisation of 3D Warp Interlock Woven Fabrics

3D warp interlock fabrics have been used both in composite materials as fibrous reinforcement as well as in protective solutions against impact mainly due to their improved capacity to absorb energy by higher intra-ply resistance to delamination. However, depending on the type of architecture used, the binding warp yarns may provide different types of mechanical behaviour. By the same, the choice of the yarn raw material coupled with the suited 3D warp interlock architecture is still a challenge to solve due to the lack of knowledge on the optimized fabric parameters to be chosen. Thus, to fill this gap, we have designed, produced on same dobby loom and tested different types of 3D warp interlock architectures (O-T 4 3–4 Basket 3–3 and A-T 4 5–4 Twill 6) with different types of raw material (E-glass EC9 900 Tex, para-aramid 336 Tex and flax Tex 500 yarns). Thanks to these tests, it has been highlighted different mechanical behaviours of 3D warp interlock fabrics with the same weave pattern but with different types of yarns (E-glass, flax and para-aramid) both in the warp and weft directions. It has been also revealed that the warp shrinkage of warp yarns inside the woven structure has a major influence on the whole fabric behaviour.

Minimum reinforcement ratio in TRC panels for deflection hardening flexural performance

The performance of textile reinforced concrete (TRC) was investigated with considering different parameters of fabric such as yarn type, mesh size, and yarn diameter. The fabric material was made of special Nylon yarns called “tire cord yarn”. In addition, the effects of thickness and reinforcement ratio on the flexural performance and ultimate capacity of TRC composites were studied. Sixty-five specimens were tested under four point flexural tests and minimum reinforcement ratio to achieve deflection-hardening behavior was obtained experimentally. Analytical formulation was presented for minimum reinforcement ratio and verified with experimental results. The behavior of specimens indicated that ultimate strength of the reinforced composite with the same reinforcement ratio, increases with increasing yarn Tex, and smaller mesh size improve the performance of samples with the deflection-hardening behavior. The experimental results showed that uncrack capacity of specimens raised by increasing reinforcement ratio, which could be due to shrinkage of yarns in cement media that behave as pre-stressing for concrete. In addition, results showed that the effectiveness of twisted yarns is about fifty percent lower than of the untwisted ones.

Melt-spun talc-filled polypropylene fibers and yarns with higher thermal shock resistance

An increase in the application areas of textiles has resulted in the need for improved and additional properties and functions, which should be provided by polymers with different functionalities or the addition of particles to the fibers. In the framework of this study, microsized talc particle-filled polypropylene (PP) fibers and yarns were produced and the mechanical, physical and thermal properties of the fibers and yarns were analyzed with respect to production parameters. The main motivation of the selection of talc as the filler material is to improve the thermal shock resistance and decrease the shrinkage of PP fibers and yarns. As a result of experimentation, it was observed that an increase of talc ratio decreases the tensile strength of fibers and yarns. However, this reduction does not seem to be an obstacle to produce fabrics. Furthermore, the addition of microsized talc particles in PP yarns dramatically improved thermal shock resistance and helped to decrease the shrinkage of these yarns.

The Comfort Properties of Two Differential-Shrinkage Polyester Warp Knitted Fabrics

Abstract Single-layered warp knitted fabrics were produced by the 60D/36F (containing 36 filaments) polyester yarn with differential shrinkage (DS) property in this study. Due to the differential shrinkage property, the fabric becomes curly and bulkier, simulating cotton fabric in terms of its appearance and fabric handle. The performance and appearance of these DS polyester warp knitted fabrics were evaluated objectively and subjectively. The testing results demonstrated that the DS polyester warp knitted fabric had better abrasion property, worse pilling resistance due to the mechanical property of polyester yarn when compared with 100% cotton warp knitted fabric. Meanwhile, lower water vapour permeability and air resistance were found for DS polyester warp knitted fabric resulting from the dense structure of yarn shrinkage after heat-moisture treatment. Besides, the fabric handle was evaluated by Kawabata evaluation system and subject to trial under dry and wet fabric condition. DS polyester warp knitted fabrics provide better recovery under low stress mechanical pressure. The subjective evaluation result shows that the warp knitted fabrics made of DS polyester had similar handle against cotton warp knitted fabric in terms of prickle, smooth, comfort and dry feeling in both dry and wet testing conditions.

About optimal architecture of plant fibre textile composite for mechanical and sorption properties

The aim of this work is to establish simple rules to optimise the architecture of plant woven fabric reinforcement for structural composite applications (sorption and mechanic aspects). For that, the influence of architectural parameters of reinforcement such as the frame, the yarn diameter, the pick count, and the filling rate, was studied from six different flax fabrics (2 quasi-unidirectionals and 4 balanced twills) and two processing techniques (autoclave and hot platen press). On the one hand, in order to normalise the effects of fibre fraction, porosity fraction and architectural parameters, a model was developped to analyse the mechanical properties at the level of the yarn. On the other hand, after demonstrating that the classical model of Fick does not properly fit the sorption of plant fibre textile composite, a two-phase Fick’s diffusion model was applied. It results that the best fabric architecture concerning mechanical and sorption properties is a compromise mixing high filling rate of woven fabrics, small shrinkage of yarns, and small yarn diameter.

Comparison between artificial neural network and response surface methodology in the prediction of the parameters of heat set polypropylene yarns

In the present paper, a response surface model has been introduced to predict the geometrical parameters of heat set polypropylene pile yarns. The input factors of the presented model include yarn twist, initial yarn count, time, and temperature of heat setting and the response factors are yarn count, yarn shrinkage, crimp contraction and packing factor after the heat setting process. To analyse the effect of this process on the yarn parameters, the dry heat setting process has been applied to all samples at different times and temperatures using an oven equipped with air circulation because of better accuracy and control of temperature. The obtained results showed that there is a positive relation between time and temperature and output parameters. Finally, the predicting equations discussions about the optimum points for maximum shrinkage and interactions of parameters have been presented. Hence, due to some disability of the RSM method, an ANN model has been designed to predict the parameters at higher accuracy. The results of the accomplished ANN model represent a higher prediction correlation coefficient compared to RSM.

Studies on cotton–acrylic bulked yarns produced from different spinning technologies. Part I: yarn characteristics

The effects of different factors, namely spinning technologies (ring, rotor and DREF-II, i.e. Group A yarns), position of shrinkable acrylic feed sliver in DREF-II friction spinning system (Group B yarns) and proportion of shrinkable acrylic core fibre in core-sheath type DREF-III friction spun yarns (Group C yarns) on various properties of cotton-acrylic–blended bulked yarns have been studied. The bulk in the yarns was developed by relaxing shrinkable acrylic component of the yarns using boiling water treatment. All the above factors have a significant impact on various properties of cotton–acrylic blended bulked yarns. For all the yarns, after boiling treatment, there is lengthwise shrinkage of yarns and the specific volume also increases. Tenacity and breaking elongation of all the yarns of Group A and Group B increase after hot water treatment, whereas in case of core-sheath type DREF-III yarns (Group C yarns) there is drop in tenacity and breaking elongation after similar treatment. In general, for all the yarns the flexural rigidity of the yarns reduces and compressibility and compressional recovery of increases after bulking treatment.

Characteristics of Traditional Textile "Awa Shijira"

Awa Shijira fabric is a crepe cotton fabric made of cotton that is woven alternating the plain and the rib texture in the weft direction. Both the warp and weft yarns are usually sized with starch, before weaving. In the course of desizing process the fantastic crepe texture is formed due to the shrinkage of yarns especially in the weft direction. Thus, the geometrical roughness for the fabric desized tends to become obvious in the weft direction. The mechanical and surface properties for four kinds of traditional Awa Shijira fabrics were investigated comparing those for the plain cotton fabric. The roughness property measured based on KES has become marked in the weft direction for the fabrics having smaller values of the shear properties in the weft direction. Also, Shijira fabrics used in this study have shown higher frictional, bending and compression properties. Moreover, there observed no remarkable differences in the mechanical properties between nationally guaranteed traditional Shijira fabric and the one guaranteed by Tokushima prefecture.

Using a bench-top rotor spinning system to measure variation between individual fleeces for predicting yarn and fabric characteristics

There is limited information available on variation among individual fleeces in yarn and fabric performance. In this study, 45 mid-side fleece samples (~30 g clean wool) with a wide range in fibre diameter, fibre diameter variation, curvature and felt ball diameter were used to determine whether these fleece characteristics significantly affected yarn and fabric shrinkage, and fabric pilling. Mid-side wool samples ranged from 13.5 to 24.0 µm mean fibre diameter, 46–108°/mm curvature and 22.2–30.2 mm felt ball diameter. Yarn felt shrinkage was significantly (P &lt; 0.001) correlated with fibre diameter (r = –0.52), and total yarn shrinkage (r = 0.99). Fabric felt shrinkage was significantly (P &lt; 0.01) correlated with curvature (r = –0.62), standard deviation of curvature (r = –0.60), and felt ball diameter (r = –0.51). Fibre diameter and curvature accounted for 31% of the variation in yarn felt shrinkage. Standard deviation of curvature and felt ball diameter accounted for 33% of the variation in fabric shrinkage. Fabric pilling was significantly (P &lt; 0.001) correlated with fibre diameter (r = 0.65), with fibre diameter and standard deviation of curvature accounting for 48% of the variation in fabric pilling. These results show that it is possible to predict yarn and fabric shrinkage and fabric pilling outcomes of individual fleeces using raw wool parameters. This study indicates that there is considerable phenotypic variation between individual Merino fleeces in the properties of yarn and fabric produced, suggesting that it is possible to quantitatively select individual sheep directly for yarn and fabric outcomes to improve the consumer performance of woollen fabrics.

Modelling of yarn shrinkage due to washing

Yarn shrinkage due to washing is modelled using the idea of helical model of yarn. The derived theoretical relation between yarn shrinkage and yarn twist intensity is experimentally verified. It is proved that yarn shrinkage increases non-linearly with the increase in yarn twist intensity.

Prediction of Yarn Shrinkage using Neural Nets

In this study, the shrinkages of warp and weft yarn in the finished woven fabrics can be estimated by neural net. The shrinkages of warp and weft yarn in woven fabrics are affected by various factors such as loom setting, fabric type, and the properties of warp and weft yarns, which are hard to be defined and estimated. The neural nets are used to find the relationships between the shrinkage of yarns and the cover factors of yarns and fabrics. The prediction of yarn shrinkage in the off-loomed fabrics can thus be fulfilled through a prediction model constructed with neural net.

Effect of spinning speed on the structure and physical properties of filament yarns produced from used PET bottles

AbstractIn the previous work (S. Kiantash, MS Thesis, Amirkabir University of Technology, Textile Engineering Department, Tehran, Iran, 2002), the possibility of producing filament yarns from used PET bottles was investigated and the production was successfully carried out. To improve physical properties and to have a detailed understanding of the molecular structure, spinning variables such as the take‐up speed (one of the most influencing factors) should be varied and studied. In the present work, continuous filament yarns from virgin PET chips and used PET bottles were produced at the two take‐up speeds of 2500 and 3000 m/min. Optical birefringence, crystallinity (obtained from three methods including density, calorimetry, and FTIR), tenacity, breaking elongation, initial modulus, and shrinkage of yarns were measured and compared. Optical birefringence and crystallinity (obtained from all three methods) of used samples show higher values compared with those of virgin samples produced at both take‐up speeds. Consequently, the tenacity of used samples is higher and breaking elongation is lower. Generally, samples having bigger crystallinity present higher initial modulus and smaller shrinkage. However, results of initial modulus and shrinkage do not correspond to this assumption. As it was predicted, increasing the take‐up speed resulted in an increase in the optical birefringence, crystallinity, tenacity, and initial modulus and a reduction in the breaking elongation of both virgin and used samples. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3972–3975, 2007

Compression properties of weft knitted fabrics consisting of shrinkable and non-shrinkable acrylic fibers

High-bulk worsted yarns with different shrinkable and non-shrinkable acrylic fibers blend ratios are produced and then single jersey weft knitted fabrics with three different structures and loop lengths are constructed. The physical properties of produced yarns and compression properties of produced fabrics at eight pressure values (50, 100, 200, 500, 1000, 1500 and 2000 g/cm2) were measured using a conventional fabric thickness tester. Then, weft-knitted fabric compression behavior was analyzed using a two parameters model. It is found that at 40% shrinkable fibre blending ratio the maximum yarn bulk, shrinkage, abrasion resistance and minimum yarn strength are obtained. It is also shown that high-bulk acrylic yarn has the highest elongation at 20% shrinkable fibre blend ratio. The statistical regression analysis revealed that the compression behavior of acrylic weft-knitted fabrics is highly closed to two parameter model proposed for woven fabrics. It is also shown that for weft-knitted structure, there is an incompressible layer (V′) which resists against high compression load. Acrylic weft-knitted fabrics with knit-tuck structure exhibit higher compression rigidity and lower softness than the plain and knitmiss structures. In addition, at 20% shrinkable fibre blend ratio, the high-bulk acrylic weft-knitted fabrics are highly compressible.

The effect of blend ratios of unrelaxed and relaxed acrylic fibres on physical properties of high-bulk worsted yarns

High-bulk acrylic yarns which contract and increase in bulk during the heat relaxation process are produced by blending two types of fibres with different shrinking power in the spinning process. In this paper, high-bulk acrylic yarns (steamed and dyed) with different shrinkable fibre blending ratios were produced. Experimental results show that by increasing the shrinkable fibre blending ratio up to 40%, the specific volume and shrinkage of both dyed and high-bulk acrylic yarns are steadily increased while their tensile strengths are decreased. Further increasing the shrinkable fibre blending ratio causes the specific volume and tensile strength properties to decreased and increased respectively. However, the yarn shrinkage does not change significantly. It is also found that both dyed and high-bulk acrylic yarns have the highest elongation at 20% shrinkable fibre blending ratio. In general, the specific volume and tensile strength of high-bulk acrylic yarns are more than those of dyed acrylic yarns but their shrinkage and elongation values are similar.

Effect of Chenille Yarn Parameters on Yarn Shrinkage Behavior

The effects of chenille yarn properties—pile material type, pile length, and twist level—on the boiling shrinkage behavior of chenille yarns are examined in this study. Different chenille yarns are produced on a chenille machine using a range of pile material types, twist levels, and pile lengths. Nm 4 and Nm 6 count chenille yarns are produced from different pile materials of viscose, acrylic (0.9 dtex), acrylic (1.3 dtex), combed cotton, carded cotton, and open-end cotton, in two different pile lengths of 0.7 and 1.0 mm and two different twist levels of 700 and 850 T/m. The results indicate that pile material types, pile lengths, and twist levels have significant effects on the boiling shrinkage of chenille yarns.

Developing seamless shaped woven medical products

Currently, the cutting and sewing process is utilized to produce medical products with tailored shape, which leads to a number of adverse consequences due to seams. These drawbacks have prompted us to undertake research to develop new methods by which seamless tubular woven products with inherent shape could be produced. The methods could potentially lead to the design and production of seamless shaped textiles that might be used in a wide variety of medical applications. Three variables were tested, specifically yarn shrinkage, weave designs, and thread density. A variety of samples were woven using different combinations of these variables to create structures with different shrinkage properties. Upon finishing in a solution containing a surfactant and soda ash, the structures experience different degrees of shrinkage resulting in desired shapes. Length and width dimensions of each sample were taken before and after finishing. The change in sample shape due to differential shrinkage in terms of yarn shrinkage, weave, and thread density is reported.

Evaluating Yarn Crimp with Fractal Geometry

Fractal geometry is used to evaluate the irregularities of crimped filament yarns. To measure the fractal dimension of textured filament yarns, methods based on the box counting dimension, the compass dimension, and the equipaced dimension are applied to digital images of the textured filament yarns, obtained using a charge coupled device (CCD) camera. For textured PET filament yams, as the crimp and twist level increase, higher values of fractal dimension are obtained, confirming that the fractal dimension can be used to evaluate fiber crimp. The fractal dimension and crimp also show an exponential relationship, which is well verified experimentally. Therefore, time-consuming direct measurements of fiber crimp may be effectively replaced by this automatic process, based on the acquisition of crimp images and fractal dimension analysis. The ideal sine wave. which has an equal length, crimp, and twist per meter, is synthesized as a topological model to study the physical properties of crimped yarn. This sine wave study shows that the major parameter of the crimped structure is the period of the crimp, and the dominant effect of yarn shrinkage development in boiling water is the increment of crimp amplitude.