Relative Water Vapour Permeability Research Articles

The water vapour resistance dynamic measurement of natural and synthetic fibre

PurposeThe paper aims to investigate the dynamic measurement of the water vapour resistance. The water vapour diffusion kinetics depends on the fibre’s material. So, water vapour resistance measurement times till the equilibrium steady state can vary in the case of natural fibres compared to synthetic fibres. Devices for determining water vapour resistance according to the ISO 11092 standard allow static values to be measured.Design/methodology/approachIn this study to investigate the dynamic of the water vapour resistance, a new parameter named “holding period” was introduced and defined as the time from sample placement on the measuring head until the measuring process begins. The holding period was varied as 0, 30, 60, 90, 120, 180, 240 and 300 s. Wool and cotton knitted fabrics were tested as natural fibres and compared to 100% polyester and 90% polyester/10% elastane as synthetic fibres. Measurements were conducted under both air velocities of 1 and 2 m/s. The experimental test data were statistically analysed based on ANOVA and four-in-one residual plots.FindingsStatistical analysis of experimental tests shows that the holding period affects water vapour resistance in both air velocities of 1 and 2 m/s and on the measured values in the case of hydrophilic fibres.Research limitations/implicationsThe study of the dynamic relative water vapour permeability of natural and synthetic is an important area of interest for future research.Practical implicationsIt is recommended to hold the samples on the top of the head measurement before starting the test.Originality/valueFollowing the ISO 11092 standard, the static values of the water vapour resistance were measured without considering the dynamic behaviour of the water vapour diffusion through the textile fabrics. This paper fulfils an experimental dynamic measurement of the water vapour resistance.

Linear regression analysis of properties related to moisture management using cotton–polyester knitted fabrics

The complex evaluation of thermo-physiological comfort for a particular garment is still challenging, as it depends on the different structural parameters and individual properties of textiles. Measurement of relevant fabric characteristics requires very specific laboratory equipment, such as an M 290 moisture management tester (SDL ATLAS) or similar. For this reason, it is obvious that there is a great demand to predict the overall moisture management capability ( OMMC) based on the individual properties that are responsible for clothing comfort and testing according to different standards rather than OMMC-specific calculation using the M 290 tester. Therefore, in this research, linear regression analysis was performed using MATLAB software to predict the OMMC for cotton–polyester fabrics knitted in two patterns, namely 1 × 1 rib and half-Milano rib, using four percentages of fibers. Water vapor permeability, water vapor resistance, water absorption capacity, water absorption time, and air permeability were used as input variables for linear regression analysis to predict the OMMC of fabrics. The performed analysis has shown that the OMMC is directly dependent on the relative water vapor permeability and air permeability, and the linear regression equation suggested in this research can predict the suitability of a textile for a particular garment concerning its moisture management behavior.

Effect of knitting structure and dyeing process on drying time, air and vapor permeability

Comfort is the prime need in clothing. It is affected by the properties of fibers, yarns, and fabrics. A good understanding of these factors is essential in the design and conception of functional clothes. Fabric design serves as a manufacturing tool to meet several end-use requirements. The construction specifications and design of knitted fabrics greatly influence the comfort level of the end-use garment. This study aims to investigate the effect of the knitting stitch type and the dyeing process on the clothing comfort of knitted fabrics. For this purpose, five structures were prepared by combining plain, float and tuck stitches: plain jersey, cross miss 1 × 1, single cross tuck, weft lock knit and Lacoste. Then, yellow, and black dyeing were applied. The investigated wear comfort properties were the drying time, the air permeability and the relative water vapor permeability. Tests were conducted on the finished and on domestically washed fabrics. The data obtained were statistically evaluated with Pearson correlation, paired t-test, analysis of variance analysis and the Tukey test. The results showed that tucked fabrics have the longest drying time combined with the lowest air and water vapor permeability. Black variants showed better drying behavior and higher water vapor permeability. Analysis of variance results showed that the structure has a significant effect on clothing comfort. However, the dyeing process exerts a significant influence only on the drying time and the relative water vapor permeability. The paired t-test results indicate that the domestic washing cycles significantly change the drying time and the air permeability of knitted fabrics.

Thermal Comfort Properties of 100% Cashmere Knitted Fabrics

The purpose of this research is to investigate the effects of knitting type (plain, rib, purl), knitting tightness (three different loop lengths), and plied-yarn (single-ply, two-ply and three-ply) on the thermal comfort properties of cashmere knitted fabrics. Thermal comfort properties of the sample fabrics were measured using Alambeta, Permetest, Textest 3300. Subsequently, the results were statistically evaluated with SPSS program. The findings of this research revealed that the knitting type, knitting tightness and plied-yarn usage significantly affect certain thermal comfort properties of cashmere knitted fabrics. Specifically, the plain knitted fabric exhibits the lowest thermal resistance value and the highest relative water vapor permeability value. The loose knitted fabric demonstrates the highest air permeability, while the fabric knitted with single-ply yarn has the lowest thermal conductivity and thermal resistance values, as well as the highest relative water vapor permeability and air permeability values.

Hybrid knitted fabric for electromagnetic radiation shielding: thermo-physical properties

Textile materials for protection against electromagnetic radiation are used now not only for special purposes but in everyday clothing too. In this regard, the thermo-physical properties of such materials are very important. In this study, the hybrid knitted fabrics with electromagnetic shielding properties manufactured on 8E flat-bed machine from 0.12 mm stainless steel wire and 30 × 2 tex cotton yarn have been tested. Fabric samples differ by variant of stainless steel wire incorporation (separately or along with cotton yarn) and their positioning in the structures (loop and/or tuck). Hybrid fabric formed by the alternation of two courses of rib 1 × 1 from cotton yarn and two courses from steel wire has higher porosity and therefore higher relative water vapor permeability and lower thermal conductivity compared with fabric formed from cotton yarn and a steel wire simultaneously. The research results showed that the introduction of stainless steel wire along with cotton yarn into the knitted structure leads to changes in stitch density and therefore in the area of porosity compared with cotton fabric. The thermal conductivity coefficient and evaporative resistance of these fabrics are similar to cotton 1 + 1 rib fabric. Thus, the studied hybrid knitted fabrics with shielding properties against electromagnetic radiation can be recommended for clothing manufacturing. The half-Milano rib fabric knitted from cotton yarn and a steel wire with the greatest electromagnetic interference shielding effectiveness has a good level of comfort similar to cotton fabric.

Evaluation of the moisture management and air permeability of cotton/antistatic polyester knitted fabrics

This research fills in the missing knowledge on the moisture management and air permeability of knitted fabrics developed using mixed cotton/antistatic polyester yarns with both antibacterial and antistatic behavior to enhance their functionality. The effect of the knit pattern, technical side, percentage of fiber mixture and treatment on water absorption capacity and time, relative water vapor permeability and resistance, and air permeability of developed fabrics was investigated. The 1x1 rib knit and half-Milano rib knit patterns were applied in each 4 percentages of cotton and antistatic polyester and 3 types of finishing to prepare 24 fabrics. The water absorption capacity for 1x1 rib knit fabrics was in the range of 182–231% and 162–237% for the half-Milano knitted fabric with the ∼20% increase when increasing the percentage of antistatic polyester or applying the treatment. The water absorption time depended on the pattern, the fabric treatment, and the percentage of the fiber mixture. The applied antibacterial treatment significantly prolonged the water absorption time of most of the dyed and softened samples. The 1x1 rib knitted fabrics showed significantly higher water vapor and air permeability than the half-Milano rib knitted fabrics. The relative water vapor and air permeability of the treated samples increased significantly with an increasing percentage of polyester. Research results are of great practical value when designing new textiles and simulating mathematically their comfort behavior when choosing them for a particular garment.

Investigation on Thermal Comfort Characteristics of Newly Engineered Yarn Umorfil® Knitted Fabrics

This study investigated the thermal comfort properties of knitted fabrics produced from newly engineered Umorfil® yarns and their blends with Tencel®, wool, acrylic and polyester yarns. Single jersey-knitted fabrics were produced with 50/50% blended yarns (Umorfil®/Tencel®, Umorfil®/wool, Umorfil®/acrylic, and Umorfil®/polyester) and with 100% Umorfil® yarn for comparison. In this regard, the thermal comfort properties (thermal conductivity, thermal resistance, thermal absorptivity), air permeability, relative water vapour permeability, water absorbency, and wicking characteristics of these fabrics were measured and evaluated statistically. The results revealed that, 100% Umorfil® and 50/50% Umorfil®/Tencel® fabrics provided better characteristics in terms of thermal conductivity, air permeability, water absorbency, wicking behaviours, and colder feelings for the use of fabrics in hot climate products. It is also suggested that owing to the synergistic effect of these two materials, the blend of Umorfil® with Tencel® enhanced the thermal comfort and liquid moisture transmission capacities of the fabrics.

Effect of Tuck Loops on Fabric Properties of Cardigan Derivative Structures

Exploring the effect of tuck loops on fabric properties of some knitted structures was aimed in this study. Samples were produced on a Stoll V-bed knitting loom with 100% acrylic yarn. Five types of knit structures (1x1 rib, half cardigan, double half cardigan, cardigan and double cardigan) were knitted with identical machine settings. Test results revealed that double cardigan fabric has the highest fabric thickness, thermal resistance and coefficient of friction. Double half cardigan provides the highest air permeability, whereas 1x1 rib structure has the highest relative water vapor permeability, mass per unit area and loop length. Half cardigan has the highest bending rigidity. Half cardigan and double half cardigan both have the best pilling results. It was observed that test results of half cardigan-double half cardigan and cardigan-double cardigan are generally similar as pairs. However, dimensional, mechanical and comfort characteristics of 1x1 rib fabric seem quite different.

Effect of plasma treatment on polyester knitted fabrics: Part I - Thermal comfort

Plasma-treated thermal comfort properties of four different types of polyester knitted fabrics (spun, continuous filament, micro denier and hollow fibre polyester), have been studied. The oxygen plasma treatment shows an encouraging effect on the air permeability, thermal conductivity, relative water vapour permeability, and wicking of the fabric samples. The findings mostly depend on the oxygen gas, loop length parameter and the thickness of the fabric. The oxygen plasma treatment also affects the thickness of fabric. The plasma-treated micro denier fabric, having courser count with higher loop length, shows higher air permeability. The plasma-treated hollow fibre polyester fabric has higher water vapour permeability, higher thermal conductivity and the highest wicking height.

Development and characterization of socks with improved anti-odour, thermo-regulating and handle properties

Due to awareness of the potential threats of spreading diseases, the demand for antimicrobial fabrics in the world market has grown significantly and, is, expected to increase the share of medical textiles in the future world market. The purpose of this study is to develop antibacterial socks with the application of silver particles and to study thermo- physiological properties as well as the evaluation of tactile sensory perceptions of treated socks against untreated socks. Socks, which are a necessary item of clothing, need to be comfortable and affordable. The materials used for this study are cotton and polyester fibre with three different cross-sectional shapes i.e., common Polyester (round shape), Coolmax (Channeled polyester) and Thermolite (Hollow polyester). Blend ratios with percentages of 80/20 Cotton/Polyester, 80/20 Cotton/Coolmax and 80/20 Cotton/Thermolite were used as main yarns in plain crew socks while elastane yarn is used in the same percentage in all developed socks. A comparison between the samples treated with silver particles and the corresponding control samples concerning the selected properties was done. The presence of particles on the treated fibre was confirmed through an SEM study. Testing of untreated and treated fabrics for antibacterial study and odour test was carried out and found significant. The thermo-physiological properties such as air permeability, relative water vapour permeability % and thermal resistance were also studied and found better results as compared to untreated samples. Later tactile sensorial comfort i.e., fabric hand value was compared which is improved for treated samples which makes the wearer comfortable hand feeling. These data present a great interest to socks manufacturers who can make better choices to manufacture, cost-effective anti-odour socks.

Size effect of carnauba wax nanoparticles on water vapor and oxygen barrier properties of starch-based film

Barrier properties against water vapor and oxygen were critical for starch-based nanocomposite film. In this study, size regulation of carnauba wax nanoparticle was utilized to adjust multi-scale structure of starch-based film, which intended to improve barrier properties. CW70 with 73.8 nm nanoparticle showed less disrupted starch hydrogen bonding, more ordered double helices, higher starch crystallinity and larger size of micro-ordered region compared with other nanocomposites. These changes of multi-scale structure of CW70 led to the lowest relative water vapor permeability (WVP, 0.86) and oxygen permeability (OP, 0.49) among all nanocomposites. Notably, water vapor could form new hydrogen bonding with starch, and the ratio of amorphous region was significantly negative correlated with WVP. Cohesive energy density was the determining factor for OP, and significant negative correlation was found between the size of micro-ordered region and OP. New knowledge from this study will advance the understanding of starch-based nanocomposite film barrier properties.

Selected barrier properties of some disposable protective coveralls in wet state

Certain types of disposable protective clothing should protect its user against liquids including water; therefore, the knowledge of their thermophysiological and barrier properties in wet state is important, as moisture mostly deteriorates comfort-related barrier properties of clothing, namely its water vapour permeability and thermal insulation. However, papers on comfort-related barrier properties are almost missing, as testing of these properties in wet state is very uneasy, due to long times of testing of these properties in standard commercial instruments. If the testing time exceeds 15 to 30 minutes, the sample gets dry and the testing is practically impossible. In the study, a special testing instrument is presented, which enables to measure water vapour permeability and thermal resistance of wetted fabrics within a few minutes, thus making possible the determination of these parameters with satisfactory precision. By means of this unique instrument and other instruments, water vapour permeability, air permeability and hydrostatic resistance of 6 wetted protective coveralls were determined. The main finding of the study is that due to the absorbed moisture, the effective relative water vapour permeability of the studied clothing gets substantively reduced, as well as their air permeability.

INFLUENCE OF ANTISTATIC POLYESTER FIBERS ON THE PROPERTIES OF COTTON AND POLYESTER SINGLE JERSEY KNITTED FABRICS

In this research, the influence of the antistatic polyester fibers containing carbon black on the comfort properties of 100% and blended cotton as well as on 100% and blended polyester single jersey knitted fabrics was evaluated. The research results revealed that the behavior of the investigated knitted fabrics was dependent on their structure and mechanical characteristics. The electrical resistance of knitted fabrics decreased significantly due to the use of 4% antistatic polyester fibers. The electrical resistance of the pure and blended cotton knitted fabric was lower than that of the pure and blended polyester knitted fabrics. Antistatic polyester fibers positively influenced the air permeability of the polyester knitted fabric. The air permeability of 100% and blended cotton fabrics was approximately 3.5 times compared to both 100% and blended polyester fabrics, respectively. The carbon black polyester fibers influenced the decrease in thermal resistance, the increase in vapor permeability, and the minor increase in vapor resistance of both cotton and polyester knitted fabrics. Thermal resistance was lower, water vapor resistance was significantly higher, and relative water vapor permeability was slightly lower for the cotton and cotton/antistatic polyester knitted fabrics than for the polyester and polyester / antistatic polyester knitted fabrics, respectively. Therefore, the research results revealed that the presence of 4% antistatic polyester fibers in cotton and polyester knitted fabrics positively influenced their antistatic behavior and improved or almost did not alter their comfort properties.

Influence of flock coating on the thermophysiological comfort properties of woven cotton fabric

In flock coating, the fabric surface is coated with an adhesive, and flock fibers of a certain length and fineness are impinged and embedded on the adhesive. Embedded fibers form a pile structure on the surface, causing the process to find a wide range of applications. However, there has been no study on the comfort properties of the flock coated fabrics due to the inevitable decrease of the fabric permeability after adhesive coating. This study evaluates the flock fiber physical properties, adhesive coating ratio, and flocking duration on the comfort properties of flock-coated fabrics. Three different coating ratios, two different flocking durations, and four different flock fibers with different fineness and length were studied. Fabric samples were produced by electrostatic flock coating of the woven cotton base fabric. In addition to the experimental study, a mathematical model has been set up to predict the flock-coated fabric thermal resistance. Short (0.4 mm) and long (1.0 mm) flock fibers have assured 82% and 204% higher thermal resistance, respectively, compared to the base fabric thermal resistance of 7.37 (10−3 m2 K/W). The thermal resistance mathematical model results have been found to agree with the actual values with a correlation coefficient of 0.95. Compared to the base fabric, long flock fiber has provided a 249% increase in thermal resistance, with at most a 20% fabric mass increment and 24% relative water vapor permeability decrease. The findings indicate that flock coating can be utilized in cold-weather clothing.

Thermo physiological comfort of single jersey knitted fabric derivatives

The main aim of this study is to determine the thermo-physiological comfort properties of single knit fabrics and their derivatives. As the Single Jersey knitted fabrics are the most widely used fabrics in the apparel sector, they have been selected for the analysis purpose. Derivatives of single jersey are developed and compared in order to understand the influence of structural variations. Physical properties e.g. thickness and areal density were evaluated for all knitted fabrics with 100% cotton yarn having three different yarn linear densities and after different stages of relaxation. Various thermo-physiological properties have been studied by changing the combed cotton yarn linear density as well as the structure of single knit fabric. Air permeability, thermal insulation and relative water vapor permeability of the fabrics were observed and investigated under wet relaxed states. It is determined that fabric physical properties are affected by changing yarn linear density and by the dry or wet relaxation stages. The percentage/number of tuck stitches (NTS), location of tuck stitches (LTS) and ratio of tuck to knit stitches (RTKS) have strong influence on physical and thermo-physiological properties of single knit fabrics, even though other knitting parameters remained the same.

Compact Spinning in Cotton-based Core-spun Yarn: A Review

In today's world, textile outfits are chosen not only for their functional properties but also for their comfort. As cotton is synonymous with comfort in textile industries, cotton-based core-spun yarn is becoming increasingly popular day by day, where the core element satisfies the functional properties and the cotton sheath provides a good hand feel and comfort. At the beginning of the twenty-first century, researchers developed a new spinning modification known as the compact spinning system to improve yarn quality. In cotton-based compact core-spun yarn, reduced hairiness, unevenness (U%), thick place, thin place, neps, and increased strength are achieved. This will also lead to significant abrasion and piling resistance, higher air permeability, lower thermal resistance, and higher Relative Water Vapor Permeability (RWVP). This review paper illustrates the advantages of spinning cotton-based core-spun yarn in the compact spinning system.

Thermal, Chemical and Mechanical Properties of Regenerated Bacterial Cellulose Coated Cotton Fabric

ABSTRACT Bacterial cellulose is a raw material that is used in many industrial areas such as textile due to its properties and an alternative to plant cellulose whose usage is increasing day by day. In this research, dissolved bacterial cellulose was used as a coating material. After the coating process, samples were immersed in three different coagulation baths to provide regeneration of the coated material. TGA, FTIR, SEM-EDX, air permeability, tensile test, thermal comfort (alambeta), and water vapor transmission (permetest) analyses were carried out to compare the mechanical, chemical, and thermal properties between raw fabric and treated fabrics. Because of chemical analysis, it was observed that the structures are similar to each other. In terms of thermal stability, it has been determined that the samples that have been coated are more durable than the raw fabric. The tensile test revealed that there was a decrease between 15.05% and 41,62% in the strength of coated materials. According to the results of air permeability, alambeta, and permetest, a decrease in air permeability values, an increase in relative water vapor permeability, and thermal conductivity values were observed with the increase of the remaining coating material in the fabric.

Visual Perception and Performance Properties of Fabrics Knitted with Elastic Core Cotton Slub Yarns

ABSTRACT In this study, dimensional, physical, visual and thermal comfort properties of fabrics knitted with elastic core cotton slub yarns were analyzed. The yarn production methods (core slub yarn and conventional slub yarn) were also compared according to the fabric properties. Additionally, the influence of slub yarn production parameters (slub thickness ratio and slub length) on the previously mentioned properties were investigated. The results indicated that elastic core fabrics produced with slub length 10 mm exhibited lower spirality property than the other fabrics. Due to their higher thermal conductivity, thermal absorptivity and relative water vapor permeability properties, fabrics produced with slub length 10 mm or slub thickness ratio 2.0 can be preferable for hot climate clothes without regard to yarn production techniques.

Experimental Comfort Evaluation of Baby Diapers In Terms of Liquid Accumulation, Moisture Management and Heat Transfer via Non Destructive Testing

The purpose of this paper is to provide an applied and objective analysis into heat transfer and mass transfer parameters such as relative water vapour permeability, thermal conductivity and thermal absorptivity as well as liquid accumulation of baby diapers which have critical importance on skin health using non-destructive Alambeta and Permetest instruments. SEM investigation was also carried out for characterization of breathable film layer of the diaper assembly. According to the water vapour transmission assessment, it was found that a few hours later, the composite diaper assembly becomes almost zero vapour permeable which results in discomfort and a poor breathability in baby diaper. It was also found that the liquid accumulation in diaper has increased in the course of time. The thickness of the diapers had an important effect on thermal parameters however production type of nonwoven top sheet and back sheet layers had a dramatic effect on these parameters.

Thermal property analysis of tri layer composite fabric towards the utility of sleeping bag

PurposeThis paper aims to investigate on composite fabrics to develop the improved sleeping bag using trilayered textile structures. A thermal comfort analysis of fabrics is essential to design an enhanced type of sleeping bag.Design/methodology/approachIn this study, optimizing thermal and permeability properties of different combinations of trilayer composite fabrics was done. The inner layer was 100% wool-knitted single jersey fabric. The middle layer was polyester needle punched non-woven fabric. The outermost layer was nylon-based Core-Tex branded waterproof breathable fabric. Five variations in wool-knitted samples were developed by changing the loop length and yarn count to optimize the best possible combination. Two different polyester non-woven fabrics have been produced with the changes in bulk density. Twelve trilayer composite fabric samples have been produced, and thermal comfort properties such as thermal conductivity, thermal absorptivity, thermal resistance, air permeability and relative water vapour permeability have been analysed.FindingsAmong the 12 samples, one optimized sample has been found with the specification of 100% wool with 25 Tex yarn linear density having 4.432-mm loop length inner-layered fabric, 96 g/m2 polyester nonwoven fabric as the middle layer, and 220 g/m2 Nylon-Core tex branded outermost layer. All the functional properties of the composite fabric are significantly different with the knitted wool fabrics and polyester nonwoven fabrics, which have been confirmed by analysis of variance study.Originality/valueThis research work supports for producing sleeping bag with enhanced comfort level.