High Air Permeability Research Articles

Breathable, Self-Adhesive Dry Electrodes for Stable Electrophysiological Signal Monitoring During Exercise.

On-skin electrodes with high air permeability, low thickness, low elastic modulus, and high adhesion are essential for biomedical signal recordings, which provide data for sports management and biomedical applications. However, nanothickness electrodes interacting with the skin by van der Waals force can be interfered with by sweating, and elastomers with high adhesion prepared by modification are not satisfactory in terms of air permeability. Here, a dry electrode with high stretchability (598%), low elastic modulus (5 MPa), high air permeability (726 g m-2 d-1), and high adhesion (6.33 kPa) was fabricated by semi-embedding Ag nanowires into nonyl and glycerol-modified polyvinyl alcohol. Furthermore, a small amount of 40 wt % ethanol was sprayed on the skin to facilitate microdissolution of the substrate and form immediate conformability with skin texture. The dry electrodes can record high-quality electrocardiogram and electromyogram signals through a robust contact with the skin under skin deformation, with a water stream, or after running for 1 h. The film can also be served as the substrate for self-adhesive strain sensors to monitor motion with higher quality than nonadhesive polydimethylsilane-based sensors.

Assessment of bacterial filtration and air permeability of face masks used by people duirng the COVID-19 pandemic

The pandemic caused by SARS-CoV-2 remains a serious threat to human health. Non-specific protection measures including face masks are an effective way to reduce risks of the infection spread. Face masks have different protective capacities and their effectiveness depends on an extent to which a material a mask is made of can retain droplets and aerosol particles containing the virus. Bacterial filtration can be used an as indicator showing how effectively a mask protects from contagion and air permeability can be used to estimate how comfortable it is to wear it. Our research aim was to comparatively assess effectiveness and comfort in wearing provided by masks which were most frequently used by people during the pandemic. We examined medical, cotton, and neoprene masks. Bacterial filtration was determined in accordance with the procedure stipulated in the State Standard GOST 12.4.136-84. Air permeability was estimated by determining how thin air was with VTPM-2 device produced by “Metroteks” LLC. All the data were statistically analyzed with StatTech v. 2.4.1 software package. We calculated quantitative indicators (M ± SD, 95 % CI for normal distribution), Fischer’s test (comparison between groups as per quantitative indicators) and Spearman’s rank correlation coefficient (directions and intensity of correlations). We developed our predictive model using linear regression. The research results indicate that the neoprene mask tends to have the highest bacterial filtration; the cotton mask, the highest air permeability. We detected a correlation between bacterial filtration and air permeability. All masks are quite comparable to a medical one as per all their combined examined characteristics and can be used as a barrier for mitigating risks of droplet infections spread. It is advisable to further investigate face masks with concentrating on more characteristics of their effectiveness, comfort in wearing and safety.

Оценка бактериальной фильтрации и воздушной проницаемости масок, используемых населением во время пандемии COVID-19

The pandemic caused by SARS-CoV-2 remains a serious threat to human health. Non-specific protection measures including face masks are an effective way to reduce risks of the infection spread. Face masks have different protective capacities and their effectiveness depends on an extent to which a material a mask is made of can retain droplets and aerosol particles containing the virus. Bacterial filtration can be used an as indicator showing how effectively a mask protects from contagion and air permeability can be used to estimate how comfortable it is to wear it. Our research aim was to comparatively assess effectiveness and comfort in wearing provided by masks which were most frequently used by people during the pandemic. We examined medical, cotton, and neoprene masks. Bacterial filtration was determined in accordance with the procedure stipulated in the State Standard GOST 12.4.136-84. Air permeability was estimated by determining how thin air was with VTPM-2 device produced by “Metroteks” LLC. All the data were statistically analyzed with StatTech v. 2.4.1 software package. We calculated quantitative indicators (M ± SD, 95 % CI for normal distribution), Fischer’s test (comparison between groups as per quantitative indicators) and Spearman’s rank correlation coefficient (directions and intensity of correlations). We developed our predictive model using linear regression. The research results indicate that the neoprene mask tends to have the highest bacterial filtration; the cotton mask, the highest air permeability. We detected a correlation between bacterial filtration and air permeability. All masks are quite comparable to a medical one as per all their combined examined characteristics and can be used as a barrier for mitigating risks of droplet infections spread. It is advisable to further investigate face masks with concentrating on more characteristics of their effectiveness, comfort in wearing and safety.

Mechanically and environmentally robust composite nanofibers with embedded MXene for wearable shielding of electromagnetic wave

Flexible materials based on two-dimensional titanium carbides (MXene) exhibit great potential for electromagnetic interference (EMI) shielding applications. However, MXene base EMI shielding materials usually cannot possess combined favorable properties of high strength, environmental stability and air permeability, which can inhibit practical implementations as wearable components. Herein, newly designed EMI shielding Poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) composite fabric with MXene embedded in nanofibers have been prepared by one-step electrospinning technique. The highly hydrophobic composite fabric shows excellent specific EMI shielding effectiveness of 160 dB/mm, which remains unchanged when exposed in acidic, alkali or saline solutions for 10 days due to the polymer matrix protection. Moreover, the embedded MXene can greatly enhance the strength and modulus of the fabric. The ultimate strength of the highly flexible composite can reach as high as20 MPa, which is 33% higher compared with untreated PVDF-HFP fabric. Our study could allow us to implement MXene based EMI shielding materials for more practical applications.

Experimental investigation on smoldering combustion for oil sludge treatment: Influence of key parameters and product analysis

Oil sludge disposal has recently become a challenge because of its large reserves and high toxicity. Smoldering combustion is a new approach for organic waste treatment where organic waste is efficiently destroyed with minimal energy input. This study aimed to explore the feasibility of smoldering combustion for oil sludge treatment with a low filling medium addition ratio. The influence of four key parameters (i.e., the moisture content of oil sludge, filling ratio, grain size, and airflow rate) on the smoldering combustion characteristics was explored. Reducing the moisture content of the oil sludge and increasing the airflow rate improved the smoldering robustness of oil sludge. The smoldering process could remain self-sustaining across sand-to-oil sludge filling ratios of 1:3–2:1, and a sand-to-oil sludge filling ratio of 2:3 was the most favorable. The oil sludge mixed with the medium-sized sand has a high air permeability, which brought about the maximum treatment rate. Detailed post-treatment analyses of smoldering products were conducted to evaluate the extent of oil sludge disposal. Smoldering combustion could completely remove volatile petroleum hydrocarbons (C10–C40) in the oil sludge, with a harmless carbon-based black residue after incomplete combustion under certain limiting conditions. Most of the metal elements in the oil sludge were concentrated in solid products after smoldering. The smoldering treatment of oil sludge has great advantages in resource recovery, and half of the petroleum hydrocarbons in oil sludge can be recovered by off-gas condensation.

Studying the influence of common wet processes on the quality of 1 × 1 rib cotton/elastane knitted fabrics

This research studied the influence of common wet processes (i.e. bleaching, dyeing, or softening) on the quality of 1 × 1 rib cotton/elastane knitted fabrics. The changes in their structural (thickness, weight, and stitch density) parameters, mechanical (bursting elongation and stiffness), comfort (air permeability and moisture sorption), and esthetic (pilling propensity) properties are discussed as an influence of the used elastane type (multifilament or monofilament), and content (4% or 8%), and applied wet processes. The severity of the bleaching process (high pH value and boiling temperature) and the resulting fabrics’ less compact structure contributed to a 17.3% higher bursting elongation of bleached compared to the dyed fabrics. Fabrics having a higher content of less finner elastane (8%, 235 dtex) have 40% and up to 21% higher stiffness and bursting elongation than fabrics containing 4% elastane of 78 dtex. The aforementioned fabrics (having 4% elastane) are softer and more comfortable since they are characterized by up to 37.9% and 5.6% higher air permeability and moisture sorption than fabrics having 8% elastane. Dyed knitted fabrics provided a better intensity of warm/cool feeling than the bleached ones due to the better comfort properties. Up to 5000 pilling cycles, the fabrics’ pilling propensity increased with an increase in elastane fineness, while at the same number of pilling cycles, dyed fabrics have a lower pilling propensity than the bleached ones. The calculated complex criterion of fabrics’ quality revealed that pilling propensity and stiffness are the main contributors to their quality that ranged from excellent to satisfying. The “satisfying” fabric quality was improved to “good” by softening with silicone softener, whereby the high content of silicon (197.51 μg/g, assessed by ICP-OES) within the bleached fabric having 8% elastane contributed to lower piling propensity compared to the corresponding non-softened fabric.

Research of protective and operational properties of sorption-filtering textile material

The article presents the results of a study on the functionalisation of synthetic textile materials with spherical activated carbon using an adhesive to create personal protective equipment based on Russian components. These materials are of particular relevance in the production of sorption and filtering personal protective equipment, which must have, along with high protective characteristics, high performance properties, vapour and air permeability. In the course of the work, the influence of the plasma of a capacitive high-frequency and low-pressure discharge on the modification of the base material was investigated. It has been proven that plasma treatment of polyester nonwoven material accelerates sorption processes, ensures uni-form coverage of fibres with a binder, which allows maintaining the material's air permeability. The results of studies of the material for the time of protective action on ammonia demonstrated the prospects for the development of Russian sorption-filtering textile material on a non-woven polyester base with a monolayer of granular activated carbon fixed on a polymer binder.

Characterization and Aerodynamics of Synthesized Polymeric Nanofibers via Electrospinning Process to Capture PM10 and PM2.5 from Air

Air quality is an important factor for human breathing requirements. The presence of the particulate matter which is a mixture of solid particles and liquid droplets presence in atmosphere such as PM10 and PM2.5 in the indoor air leads to fatal problems for human health. In the present investigation, two types of nanofilters (polyacrylonitrile PAN, 15wt.% and polyvinyl alcohol PVA 12wt.%) were synthesized using the electrospinning method. The polymeric solutions were prepared under high mixing conditions. The structural and morphological specifications of produced nanofibers were characterized using many measuring devices. Also, airflow characteristics across the prepared nanofilter were evaluated by designing and constructing an airflow apparatus. The apparatus consisted of two stainless steel sections and the middle zone was designed to fit the filter media. The characterization results indicated that the synthesized of PVA 12 wt.% nanofilter has uniform morphological distribution with fibers average diameter of 92 nm while the produced PAN with 15wt.% showed and an average fibers diameter of 556 nm. Moreover, the PVA nanofilter showed high-pressure values in comparison with the PAN filter. Interestingly, both filters provided high air permeability. Furthermore, the produced PAN nanofilter showed a high ability to capture the PM10 and PM2.5 due to the significant properties and specifications of nanofibers. Additionally, the produced nanofilter can be applied in air filtration processes effectively with low manufacturing costs.

Breathability performance of antiviral cloth masks treated with silver nanoparticles for protection against COVID-19.

The global widespread of coronavirus disease 2019 (COVID-19) has caused shortage of medical face masks and led to developing of various types of cloth masks with different levels of protection and comfort to meet the market demands. Breathing comfort is a significant aspect that should be considered during the design of cloth masks along with the filtration efficiency; otherwise, the wearer will feel suffocated. In this work, different types of cotton and polyester knitted fabrics blended with spandex yarns were produced and treated with silver nanoparticles to be used as antiviral cloth masks. Scanning electron microscope, transmission electron microscope, and EDX were used to characterize the silver nanoparticles (AgNPs). Antiviral activity was assessed against SARS-CoV-2 coronavirus as well. The influence of using different fabric materials, number of layers, and hybrid layers on their air permeability and breathability were investigated to evaluate the comfortability of the cloth masks. Physiological impacts of wearing the cloth masks were evaluated by measuring oxygen saturation of hemoglobin and heart rate of the wearers while doing various activities. The results indicated that AgNPs have low cytotoxicity and considerable efficiency in inhibition of SARS-CoV-2. Adding spandex yarns with different count and ratios reduced the porosity and air permeability of the fabrics. Moreover, the combination of three hybrid layers’ mask made of polyester fabric in the outer layer with 100% cotton fabric in the inner layer showed high comfortability associated with high air permeability and breathability. Also, wearing these masks while doing activities showed no significant effect on blood oxygen saturation and heart rate of the wearers.

Study of Thermal Comfort Properties of Different Kinds of Polyester Knitted Fabrics

This research focused on the thermal comfort behaviour of polyester with respect to the type of yarn (spun, micro denier, continuous filament and hollow), linear density of the yarn (111 and 166 dtex), and the loop length of knitted fabric (0.25, 0.27 and 0.29 cm).The air permeability of continuous filament yarn fabric and micro denier yarn knitted fabrics was noted to be higher than that of spun yarn knitted fabrics. 111 dtex micro denier yarn fabric has the highest air permeability and 111 dtex spun yarn fabric the lowest air permeability value among all the other fabric samples. Comparatively, coarser spun yarn fabric has lower air permeability characteristics than finer microdenier fabric.The water permeability of the fabric shows a significant difference between the spun yarn, continuous filament yarn and Micro denier yarn knitted fabrics and between the linear density of the yarn. The water vapour permeability of spun yarn of 166 dtex single jersey fabric is higher, while the water vapour permeability of continuous filament yarn fabric of 166 dtex is lower. The thermal conductivity value is high for continuous filament polyester fabric of 100 D and low for microdenier polyester fabric of 166 dtex. Based on the statistical analysis, it is clearly shown that there are significant differences between the three different polyester yarn fabrics of two different denier of the same fabric. Furthermore, the count and different polyester yarn affect the comfort properties of single jersey fabrics.

Thermo-physiological and Handle-related Comfort Properties of Hemp and Flax Blended Denim Fabrics

ABSTRACT This study investigated the use of flax and hemp fibers in denim fabrics in terms of thermo-physiological comfort and handle-related properties. Cotton/flax and cotton/hemp blended fabrics with 2/1 twill and 3/1 twill weaves were selected and evaluated compared to pure cotton fabric. Besides, the effect of rinsing was examined. The findings revealed that the use of flax and hemp fibers improved the thermo-physiological and handle-related comfort properties of denim fabrics. Higher air permeability and water absorbency along with quick-drying behavior could be achieved in flax and hemp blended fabrics compared to pure cotton fabric. Handle-related comfort properties of flax and hemp blended fabrics indicated soft touch. Although the extension and formability values of the blended fabrics were low, they were at an acceptable level and were improved after the rinsing process.

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.

Nanoflake-Engineered Zirconic Fibrous Aerogels with Parallel-Arrayed Conduits for Fast Nerve Agent Degradation.

Chemical warfare agents (CWAs) pose huge threats to ecological environments, agriculture, and human health due to the turbulent international situation in contemporary society. Zirconium hydroxide (Zr(OH)4) has captured the prime focus as an effective candidate for CWA decomposition but is often hindered by the isolated powder form. Here, we demonstrate a scalable three-dimensional space-confined synthetic strategy to fabricate nanoflake-engineered zirconic fibrous aerogels (NZFAs). Our strategy enables the stereoscopic Zr(OH)4 nanoflakes vertically and evenly in situ grown on the interconnected fibrous framework, remarkably enlarging the surface area and providing rich active sites for CWA catalysis. The as-synthesized NZFAs exhibit intriguing properties of ultralow density (>0.37 mg cm-3), shape-memory behavior under 90% strain, and robust fatigue resistance over 106 compression cycles at 40% strain. Meanwhile, the high air permeability, prominent adsorptivity, and reusability make them state-of-the-art chemical protective materials. This work may provide an avenue for developing next-generation aerogel-based catalysts and beyond.

Multifunctional cellulose membranes with antibacterial activity and infrared insulation properties for personal thermal management application

ABSTRACT In this work, multifunctional cellulose membranes (Ag-NWs/CMs@Ag) with antibacterial activities, high air permeability, and infrared preservation properties were successfully prepared for personal thermal management application. Infrared radiation preservation was observed by modifying surface’s physical and chemical properties. Additionally, Ag-NWs/CMs@Ag exhibits high air permeability of 3.00 mg/cm2·hour, the excellent antibacterial activity against E. coli and S. aureus and hydrophobic properties with a stable water contact angle of 129.35°. Overall, the results of this study demonstrate Ag-NWs/CMs@Ag offers great potential in personal thermal management application and provide an effective strategy for the development of wearable textiles.

Aerogel incorporated flexible nonwoven fabric for thermal protective clothing

Aerogel-nonwoven fabrics are gradually emerging as a promising alternative in the field of thermal protective textiles. Although currently available commercial aerogel-nonwovens can provide some degree of flexibility and find their way into the conventional textiles, their flexibility has not yet reached an acceptable level essential for clothing comfort. Fabric flexibility is important for the aesthetics, comfort, and functionality of clothing. This article demonstrates the design and fabrication of an aerogel-nonwoven fabric as a thermal liner in a multilayered protective clothing system that is significantly more flexible than commercial aerogel-nonwoven fabrics. The developed aerogel-nonwoven composite possesses almost similar dry and radiant heat resistance but inferior contact heat resistance in comparison to commercial aerogel nonwovens. It has high air and moisture vapour permeability compared to its commercial counterpart and will provide satisfactory thermal comfort to the wearer in hot and humid environments. The overall thermal resistance performance, together with high flexibility and moisture management capability, make the aerogel-nonwoven fabric a potential alternative to commercial nonwovens for any thermal protective clothing system where fabric flexibility and thermal comfort are the key requirements.

Preparation of a composite coating film via vapor induced phase separation for air purification and real-time bacteria photocatalytic inactivation

Infectious diseases resulted from transmitting of bacteria or virus like COVID-19 via air-borne droplets have brought severe threat to human beings worldwide. Cutting the spreading paths to obtain clean air is one of the promising strategies to prevent people from such dangerous diseases. In this work, we have employed a strategy of spray coating in combination with vapor induced phase separation to prepare a composite coating film to fulfill that purpose. A stable mixture suspension containing micelles of block copolymer of poly(styrene-block-butadiene-block-styrene) and TiO2 nanoparticles was sprayed onto stainless steel mesh to evaporate solvent in non-solvent vapor atmospheres. A water vapor atmosphere and an ethanol vapor atmosphere were in turn employed to improve the mechanical strength of the obtained coating film. The porous microstructure, the porosity, and the superhydrophobicity of the coating film were carefully characterized and analyzed. The air pressure-drop of the coating film was determined to be lower than 100 Pa, indicating a high air permeability. Moreover, a foggy air containing E. coli was pressed through the coating film via a home-made apparatus to simulate the air purification system, where E. coli contained air-borne droplets were intercepted by the film matrix in a physical manner, and the bacteria was photocatalytically inactivated at the meantime. A filtration efficiency of 99.7% and a 99.6% efficiency of real-time photocatalytic inactivation of E. coli demonstrate the promising potential of the coating film.

Thermo-physiological Clothing Comfort of Wool-Cotton Khadi Union Fabrics

ABSTRACT Khadi is a handspun and handloom woven textile fabric made up of natural textile fibers, predominantly cotton and wool. Khadi mainly intended for apparel purposes. Hence, the thermo-physiological properties of wool-cotton blended khadi fabric are crucial in studying fabric comfort. In this study, the 18 types of wool-cotton blended khadi fabrics are produced on a handloom by using wool-cotton blended yarn as warp; and woolen yarn comprised of three different mixes of Australian Merino (AM) wool and JK crossbred (JKC) as weft yarn. Two different weft yarns of 41.7 and 31.2 Tex were prepared using these mixes. The thermo-physiological properties of fabric viz. air permeability, water vapor transmission, and thermal resistance were studied. The air and water vapor permeability, and thermal resistance of wool-rich blended fabrics were found higher compared to cotton-rich blends. The air permeability is negatively influenced by the fabric cover factor. The coarser weft yarn gives higher air permeability while lower water vapor permeability. The thermal resistance is found to have a positive relationship with fabric cover factor. The wool content in yarn and weft yarn linear density largely influences the thermo-physiological comfort properties of the khadi fabric.

Long-term soil quality effects of soil and crop management in organic and conventional arable cropping systems

Improving or maintaining soil health is crucial to support human needs, with the concept of soil quality connecting soil functions and sustainability concerns. In 2019, we assessed soil chemical, physical and biological properties in a long-term crop rotation experiment initiated in 1997 at Foulum, Denmark, with the aim of determining the long-term soil quality effects of the use of cover crops, animal manure, different crop sequences (with or without a legume-based ley) and organic vs conventional management. The concentration of soil organic carbon has been relatively stable across all treatments for 14 years prior to this investigation; in 2019, we found high aggregate stability, porosity, air permeability and pore organization in all treatments. Bulk density, air permeability and pore organization were affected to some extent by soil and crop management, with bulk density being the lowest in the organic treatment without cover crops, which had the most frequent harrowing. Earthworm density was the greatest in the organic system with grass-clover, especially following the ley year, thanks to a combination of high quality plant input and reduced soil disturbance. From a system perspective, none of the treatments investigated represented extremes, and all maintained good soil quality in the long-term. This indicates that long-term management should take into account the combination of different factors affecting soil quality.

Investigation of Microstructures and Air Permeability of Aerogel-Coated Textile Fabric Materials

Abstract This study focuses on fabrication of aerogel-coated macroporous polyester fabrics for the purposes of filtration of nanometric airborne particles and potential application in facemasks. Syndiotactic polystyrene (sPS) and polyimide (PI) gels that provide respectively majority macropores (diameter > 50 nm) and mesopores (diameter 2 to 50 nm) are coated onto woven polyester fabrics via a dip coating process. The resultant materials are supercritically dried to obtain aerogelcoated fabrics. The results show that sPS is more suitable for the dip coating process. However, evaporation of the solvent during handling of gel-coated fabrics leads to closure of the surface pores that are later recovered via solvent annealing. The resultant aerogel-coated fabrics offer high air permeability (∼10–10 m2) and high filtration efficiency (> 99.95%) of airborne sodium chloride test particles of size 25 to 150 nm.

Design of sports-abaya and its thermal comfort evaluation

The market for sports-abaya in Saudi Arabia is growing due to an increasing participation rate of Islamic women in fitness and sports activities. As mandated by religious law, an abaya must be worn over daily clothes or sportswear by women in order to hide their body contour. The additional layer of the abaya will affect thermal comfort and performance of the wearer. Hence, a sports-abaya needs to be specifically designed to facilitate thermal comfort. This necessitates the selection and evaluation of fabrics appropriate for use in the production of sports-abaya. This study compared two fabrics (100% cotton knit and 100% polyester woven) for their air permeability, thermal resistance and evaporative resistance. The fabrics were then incorporated as sole variable into two models of sports-abaya. The thermal properties of these abayas were evaluated using a female thermal manikin in both standing and walking positions. Comparison was made with the results of a traditional abaya. The research work revealed that polyester woven fabric has a higher air permeability (44.9 mL/cm2/s) than cotton knitted fabric (24.1 mL/cm2/s). The vapor resistance of polyester fabric was lower than cotton fabric and their thermal resistant did not show any significant difference. Consequently, thermal manikin evaluation showed results favoring sports-abaya containing polyester fabric in both standing and walking positions. Furthermore, the thermal resistant and vapor resistant values of sports-abayas were lower compared with those of the traditional abaya. This leads to the conclusion that the newly designed sports-abaya containing 100% polyester woven fabric provides better thermal comfort than traditional abaya and sports-abaya containing 100% cotton fabric.