Impact of structural variations in hollow yarn on heat and moisture transport properties of fabrics

The use of hollow/microporous yarns plays an important role in enhancing the thermo‐physiological comfort properties of fabrics. Depending on structural variations in hollow yarn, heat and moisture regulation behaviours of fabrics can be affected significantly. In this study, three types of hollow cotton yarn fabrics, produced by introducing polyvinyl alcohol (PVA) filament in the core, PVA staple fibres in the blend and PVA filament in doubling with cotton spun yarn, are studied. All three types of pre‐hollow yarns and reference yarns are made with a variation in spinning technique (single roving/double roving) to prepare eight single jersey knitted fabrics. The hollow/microporous structure of the yarn is created by dissolving the PVA fibres using hot washing of the fabrics. On overall evaluation of the fabric’s thermo‐physiological comfort properties, the doubled hollow yarn fabrics are found to be better than other fabrics. In general, thermal resistance, thermal absorptivity, wicking and drying properties of all types of hollow yarn fabrics increase after repeated laundering, while air permeability, water vapour permeability and water absorbency of hollow yarn fabrics mostly decrease. In contrast with fabrics made from yarn produced through single roving technique, use of double roving technique only improves fabric water vapour permeability.     

Permeability properties of single jersey fabrics made of hollow yarns

In this work effect of using hollow yarns on the permeability properties of the single jersey knitted fabrics were studied. Firstly yarns were produced by ring spinning machine using cotton, viscose and acrylic fibres in the mantle and water soluble polyvinyl alcohol (PVA) fibre in the core. Single jersey fabrics were knitted and PVA core was removed subsequently by washing process to create hollow yarn. Weight, air permeability and water transmission rate properties of fabrics were measured before and after washing and compared with reference fabrics. Due to the removal of PVA fibres from the yarn core after washing treatment, air permeability and water vapour transmission rate of the all kind of single jersey fabrics which were produced with hollow yarns increased as well as weight of the fabrics decreased which will cause more comfort during any exercise. It was also found that mantle fibre type and PVA ratio have significant effect on the fabric properties.     

Effect of blend proportion on thermal behaviour of bamboo knitted fabrics

This study presents the thermal comfort properties of single jersey knitted fabric structures made from cotton, regenerated bamboo and cotton–bamboo blended yarns. Cotton, bamboo fibre and blends of the two fibres (100% cotton, 100% bamboo, 50:50 cotton:bamboo, 67:33 cotton:bamboo, 33:67 cotton:bamboo) were spun into yarns of identical linear density (20?tex). Each of the yarns so produced was converted to single jersey knitted fabrics with loose, medium and tight structures. The thermal conductivity of the fabrics was generally found to decrease with increase in the proportion of bamboo fibre. The relative water vapour permeability and air permeability of the fabrics were observed to increase with increase in bamboo fibre content. Statistical analysis also indicates that the results are significant for air permeability, thermal resistance, thermal conductivity and relative water vapour permeability of the fabrics.     

A study on thermal properties of single-jersey knitted fabrics produced from ring and compact folded yarns

This paper presents a study on the thermal properties of single-jersey knitted fabrics manufactured using ring, compact and ring/compact folded yarns. The variations in thermal properties depending on the yarn twist and traveller weight of folded yarn single-jersey knits were discussed. It was found that the thermal resistance of knitted fabrics generally increases as the traveller weight decreases, and also water vapour permeability reduces as the traveller weight decreases. The water vapour permeability and air permeability of knitted fabrics increase as the twist increases. The thermal conductivity of knitted fabrics decreases as the twist increases. The air permeability and water vapour permeability values were higher for compact folded yarn fabrics as compared to those values of ring and ring/compact folded yarn fabrics. It is observed that yarn twist and traveller weight have affected different thermal properties of single-jersey folded yarn fabrics.     

Thermo-physiological comfort properties of double-face knitted fabrics made from different types of polyester yarns and cotton yarn

Double-face knitted fabrics with hydrophobic inner and hydrophilic outer layers are characterised by their advantageous thermo-physiological comfort property that facilitates the transport of sweat from skin to outer fabric layer where it can be evaporated easily. In this study, for the production of double-face knitted fabrics, cotton yarn as hydrophilic yarn type and five different polyester filament yarns consisting of standard polyester, hollow polyester, micro polyester, textured polyester and textured micro polyester as hydrophobic yarn type were used. In order to determine the thermo-physiological comfort properties of the fabrics, air permeability, water vapour permeability, thermal conductivity, thermal resistance and overall moisture management capacity were measured. The results were comparatively analysed using statistical methods. The experimental results demonstrated that the polyester-type yarns and the combinations of them with the cotton yarn in fabric layers affected the thermo-physiological comfort properties significantly. The fabrics with polyester-type inner face and cotton outer face showed the best moisture transmission properties.     

Study on effect of blend ratio on thermal comfort properties of cotton/nylon-blended fabrics with high-performance Kermel fibre

This study presents the thermal comfort properties of woven fabrics made of Kermel, cotton/nylon and cotton/nylon /Kermel-blended yarns. Our aim in this study is to combine the high comfort properties of cotton/nylon fibres with high thermal protective properties of Kermel fibre in different woven fabrics. Thus, Kermel (100%), cotton/nylon (50:50) and four blends of the 50% cotton fibres with nylon and Kermel (40:10, 30:20, 20:30 and 10:40) were spun on a ring-spinning frame and twisted into two-folded yarns with the same yarn count of 30/2(Ne) and twist level of 560 TPM. Using the produced yarns, woven fabrics with identical characteristic and structure were also produced. Then, the thermal comfort and physical properties of fabrics were studied in terms of fabric porosity, thermal resistance, thermal conductivity, water vapour resistance and air permeability. The results show that the porosity, air permeability and thermal resistance increase with Kermel fibre blend ratio. Conversely, the water vapour resistance decreases with increase of Kermel fibre blend ratio up to 40%, while 100% Kermel-woven fabric exhibits a higher water vapour resistance value. Nevertheless, the thermal conductivity of cotton/nylon-blended Kermel woven fabric is unchanged with increase of Kermel fibre blend ratio up to 40%, whereas at 100% Kermel fibre blend ratio, the lowest thermal conductivity is obtained. The obtained results implied that woven fabric produced from cotton/nylon (50/10) blended with 40% Kermel fibre resulted in proper thermal comfort properties.     

Novel engineering approach to optimization of thermal comfort properties of hemp containing textiles

The aim of this research was to investigate the possibilities of producing comfort hemp containing textile fabrics by assembling a pure hemp yarn with other-fibre containing yarn. The plain knitted fabrics were produced from two-assembled hemp and three variants of cotton yarns which differed in twist level, all having the same linear density. The transport properties (air permeability, water vapour permeability and thermal resistance) of the hemp-based knitted fabrics were quantitatively analysed. The results obtained demonstrated that the introduction of cotton into hemp-based textiles reduces air and water vapour permeability with the downward trend in thermal resistance. The extent to which the transport properties varied among the hemp/cotton knitted fabrics was dependent on the twist intensity of the cotton yarns. Therefore, the yarn assembling technique is an effective way not only to combine different fibre properties but to take advantage of intrinsic properties of component yarns.     

Characterization based on the thermal capabilities of metallized fabrics equipped with hybrid conductive yarns for protective clothing

Electronic textiles are recognized for their conductive characteristics in various fields of research including medicine, communications, power and for the development of protective clothing. Out of the several types of conductive textile available, multi-component yarns and fabrics, produced from continuous copper filament as spiral covering on hybrid cover yarns, have never been investigated for their thermal capabilities. In this study, characterization based on the thermal properties for conventional copper core yarn’s fabric and newly developed copper cover yarn’s fabrics was carried out. The results demonstrate better conductivity of copper cover yarn’s fabrics as compared to the copper core conventional fabrics, which is attributed to its better conduction due to greater percentage of copper and direct contact between the heat flux transducers. With the higher porosity values for the newly developed fabric, the liquid water, water vapour and air transport capabilities, which are key aspects of thermal comfort, significantly improved.     

Analysis of thermal comfort properties of fabrics for protective applications

Protective clothing protects the body from external influence like heat, chemicals, mechanical hazards, bad weather, etc. by shielding the human body from harsh environmental effects. The maintenance of thermal balance is one of the most important aspects of protective clothing. The study aims to investigate the thermal comfort properties of woven hybrid fabrics produced with high performance core spun yarns. For this purpose, meta-aramid, e-glass, Technora® and Dyneema® fibres were combined using core yarn spinning method in order to enhance the protective performance characteristics. The effects of the core/sheath ratio and type of core materials on the thermal comfort characteristics were investigated and evaluated statistically. The results revealed that, core/sheath ratio, types of core materials have significant effects on thermal comfort characteristics of the fabrics. As the core ratio increases from 19 to 56%, the air permeability of the fabrics increases whereas their thermal conductivity and thermal absorptivity properties decrease. Meta-aramid/E-glass core fabrics can be preferable for protective clothing due to high air permeability and thermal conductivity values.     

Thermo-physiological comfort characteristics of polyester air-jet-textured and cotton-yarn fabrics

Air-jet-textured polyester yarns were produced using two feed yarns differing in filament fineness and number of filaments. By varying the overfed rates of feed yarns and changing their positions in core and effect, five textured yarns were produced. Woven fabrics were prepared using these textured yarns as weft and cotton yarns in warp. To study the effect of air-jet-texturing parameters on the thermo-physiological comfort characteristics of fabric, the woven fabrics were tested for thickness, thermal properties, transverse wicking and air permeability. It is observed that thermal conductivity and resistance of fabrics are not influenced by the texturing parameters/textured yarn structure. These properties are mainly dependent on the entrapped air present in fabrics. Thermal absorptivity is a transient phenomenon of heat flow reflecting that the ‘warm-cool feeling’ effect of fabrics depends on smoothness/roughness of fabric surface. Fabrics with smooth surfaces have higher thermal absorptivity values as they provide a large area of contact with human skin. The roughness of fabrics depends on the number of surface loops and filament fineness. Transverse wicking of fabrics depends on the size, continuity and alignment of the capillaries present in the core of textured yarns.     

Comfort properties of bamboo/cotton blended knitted fabrics produced from rotor spun yarns

The comfort characteristics of bamboo/cotton-blended knitted fabrics made from rotor-spun yarns were studied in this research work. Five different blend proportions namely 100% bamboo, 100% cotton, 50:50 cotton:bamboo, 70:30 cotton:bamboo and 30:70 cotton:bamboo were used to produce rotor-spun yarns of 30^sNe_c. The yarn samples developed out of these different blend proportions were evaluated for yarn strength and elongation, yarn unevenness, yarn imperfections and used to produce single-jersey-knitted fabrics. All the fabric samples were dyed and finished. Fabric samples were evaluated for geometrical properties such as course/inch, wales/inch, stitch density and thickness apart from measuring comfort properties such as airpermeability, thermal conductivity, thermal resistance and water vapour permeability. The results indicated that 50/50 bamboo/cotton-blended knits have comparable fabric quality in terms of comfort properties with respect to 100% bamboo fabrics.     

A study on thermophysiological comfort properties of fabrics in relation to constituent fibre fineness and cross-sectional shapes

The present study reports the effect of linear densities and profiles of polyester fibres on the physiological properties of their fabrics. Four different polyester fibre finenesses along with microdenier and four cross-sectional shapes (circular, scalloped oval, tetrakelion and trilobal) were selected to produce two sets of 2/1 twill fabrics; one composed of 100% polyester and the other 67:33 P/V blends. In studying the thermophysiological component of the clothing comfort, heat, air and moisture transmission characteristics of the fabrics were assessed. The principal thermal properties, such as thermal absorptivity, thermal resistance and thermal conductivity, were experimentally evaluated, using the Alambeta instrument. The study of the obtained results established the fabrics of non-circular cross-sections as against circular ones, and increase in the linear density results in higher thermal resistance, lower thermal conductivity and lower thermal absorptivity. Wicking behaviour of fabrics was studied under two conditions–wicking from an infinite liquid reservoir (transverse wicking) and wicking from a finite liquid reservoir (single drop wicking into the fabrics). Increase in fibre linear density enhances transplaner wicking but slows down the spreading speed of water drops. Air permeability and moisture vapour permeability are found to be positively correlated with fibre decitex. The role of fibre cross-sectional shapes in influencing mass-flow characteristics is quite considerable. Use of non-circular polyester in place of a circular one augments the wickability of liquid water along with the permeability of air and moisture vapour through the fabrics, revealing their high porosity, which assists air and moisture to propagate. Mixing viscose into polyester brings down the air permeability and moisture vapour transmission rate (MVTR) of fabrics. Results show that moisture absorption of viscose is an important factor in influencing the moisture transport characteristics including both wickability and MVTR of 100% viscose and P/V-blended fabrics.     

Investigation on permeability and moisture management properties of different denim fabrics after repeated laundering

The physiological comfort determined by air permeability and moisture management properties of fabrics is influenced by various constructional parameters of the fabric which give woven fabric a porous structure. Evaporation of sweat during wear has the potential to cool the body besides restricting the additional weight of sweat being absorbed by the fabric. In this study, comfort characteristics of denim fabrics with different weft yarn of cotton, polyester and core spun Lycra have been discussed. Effect of enzyme washing and repeated laundering on air permeability, moisture management and drying rate has also been discussed. It was observed that air permeability and water vapour permeability of unwashed denim fabrics with cotton weft yarn are significantly higher than the fabric with polyester and Lycra cotton weft yarns. The wetting time is higher for cotton and Lycra cotton yarn fabrics. One-way transport index is highest for Lycra cotton weft fabrics and lowest for fabrics with polyester weft. Fabrics with polyester weft yarns show highest spreading rate, spreading radius and drying rate due to better wicking and hydrophobic nature of polyester fibres.     

Studies on cotton-acrylic bulked yarns produced from different spinning technologies. Part II: fabric characteristics

The present work is concerned with the study of the characteristics of plain woven fabric produced with cotton-acrylic high-bulk yarns from different spinning technologies. The effects of different factors, namely spinning technologies (ring, rotor and DREF-II, i.e. Group A fabrics), position of shrinkable acrylic feed sliver in DREF-II friction spinning system (Group B fabrics) and proportion of shrinkable acrylic core fibre in core-sheath type DREF-III friction spun yarns (Group C fabrics) on various properties of cotton-acrylic blended bulked yarn fabrics have been reported. The influence of these three variables on the mechanical, handle and comfort properties of fabrics have been studied. The properties of fabrics made of bulked yarns from different spinning technologies are found to be different from the normal 100% cotton yarn fabrics in all respect. Even though the bulked yarns were used only in weft direction, the fabrics with modified yarn structures show appreciable improvement in thermal resistance, moisture vapour transmission, wicking and air permeability. The bending rigidity of the fabrics in weft direction also reduced with improvement in crease recovery in weft direction.     

Preparation,characterisation of bamboo charcoal particles and the effect of their application on thermo-physiological comfort properties of woven fabrics

Abstract

Bamboo charcoal particles were prepared at micro level and applied on three types of woven fabric, namely 100% cotton, 100% polyester and 65/35 p/c blend. The thermo-physiological comfort properties such as wetting, wicking, water vapour permeability, air permeability and thermal resistance of the control and treated fabrics were investigated to study the effect of bamboo charcoal particles application on these fabrics. The results reveal that the bamboo charcoal treated fabrics show a good improvement in wetting, wicking and water vapour permeability. The charcoal particle finished fabrics also showed a slight decrease in thermal resistance thereby contributing to a corresponding improvement in thermal conductivity with a reduction in air permeability when compared with the control fabrics. The bamboo charcoal treated fabrics showed a good fastness to washing thus exhibiting good durability on the fabrics selected for the study. Also, the charcoal treated fabrics revealed a higher wickability than the control fabrics even after 20 washes.     

Effect of structural parameters of porous yarns and fabric on air permeability and moisture transfer of double-face woven fabrics

In this study, effect of fabric structural parameters of double-face woven fabrics including kind of porous yarn namely micro-porous yarn and hollow yarn, hole size of hollow yarn, percentage of these yarns in double-face woven fabric structure, and finally weft density on air permeability and moisture transfer of woven fabrics was evaluated. These yarns were produced by using water-soluble continuous polyvinyl alcohol filaments as core part for hollow yarns and as doubling yarn in micro-porous yarn. Results revealed the effect of kind of porous yarn, hole size of hollow yarn, and weft density on air permeability and moisture transfer of woven fabrics. The percentage of porous yarns as weft did not show obvious trend. Analysis of variance was used to study the effect of these variables on air permeability and moisture transfer of double-face woven fabrics statistically.     

Effect of preheat setting process on heat,mass and air transfer in plain socks

Socks are prevented against wrinkle formation by preheat setting in greige form prior to wet processing. The current study is proposed to analyze the effect of socks presetting process on thermopysiological and wicking properties of comfort. In this analysis, main yarn linear density, plaiting yarn composition and number of needles are taken as variable on same machine setting. Sock samples were analyzed for comfort parameters (thermal conductivity, thermal resistivity, thermal absorptivity, thermal diffusivity, relative water vapor permeability (RWVP (%)), evaporation resistance (Ret), air permeability, vertical wicking, absorbency and color strength (K/S) value) after various processes (preheat setting, dyeing and postheat setting). The statistical analysis showed that preheat set process significantly affects vertical wicking, K/S value, absorbency, thermal conductivity, thermal resistivity and thermal diffusivity, respectively. While thermal absorptivity, air permeability, porosity, RWVP (%) and R_et couldn’t show a significant impact.     

Analysis of mechanical and dimensional properties of the denim fabrics produced with double-core and core-spun weft yarns with different weft densities

Elastic structures are preferred for improving the elasticity and recovery properties of denim fabrics. With the intention of improving comfort during body movements in denim jeans, 10–35% elasticity is required. In this study, the effect of the composition of double-core (dual-core) and core-spun weft yarns and weft density on the mechanical properties of denim fabrics was investigated. For this purpose, different core materials were used in the production of elastic yarns. The sheath material was cotton for all yarn types. Yarn samples were spun with the same yarn count and twist coefficient. 100% cotton Ne 8/1 Ring slub warp yarns were used as warp yarn while double-core and core-spun yarns were used as weft yarns in weaving. The weaving process was performed with three different weft density values (16, 22, and 28 weft /cm) and the other production parameters were kept constant. Twill 3/1 woven fabrics were treated according to standard denim finishing procedures. After domestic washing processes, mechanical properties of the samples were tested and statistically evaluated.     

Modelling to predict thermophysiological properties of hollow/microporous yarn fabrics

Hollow/microporous yarn spinning is a technique used to increase the bulk of yarn without increasing its weight. Hollowness in the cotton yarns has been introduced by various methods and techniques. Empirical models have been developed to predict the thermophysiological properties through structural parameters. Based on standardized multiple linear regression models, fabric’s structural parameters are related with thermophysiological properties of hollow yarn fabrics. Three basic parameters i.e. yarns packing density, inter-yarn porosity and fabric thickness have been found to relate strongly with fabric thermophysiological properties except water vapour permeability.     

Packing of micro-porous yarns. Part II: optimization of fabric characteristics

This paper is concerned with the study of the characteristics of plain woven fabric produced with micro-porous cotton yarns in weft. The micro-porous yarns with varying packing densities and level of pore volumes are produced by changing proportion of PVA fibre content in the blend, yarn twist multiplier (TM) and spindle speed at ring frame. The micro-pores within the structure of the yarn have been created by dissolving the PVA fibres using washing treatment in hot water. A three-variable factorial design technique proposed by Box and Behnken has been used to study the interaction effects of these variables on the characteristics of fabrics. The influence of these three variables on the mechanical, handle and comfort properties of fabrics are studied, the response-surface equations for all the properties have been derived and the design variables are optimized for various fabric properties. Improvements in bending resistance, abrasion resistance and compressional characteristics have been observed with incorporation of micro-pores within the yarn structure. These fabrics with micro-pores have improved thermal resistance and moisture vapour transmission compared to that of 100% cotton fabric.