Protective Clothing Applications Research Articles

Silver nanoparticles in electrospun ethyl hydroxy ethyl cellulose-PVA Nanofiber: Synthesis, characterization and wound dressing applications

Electrospinning is a simple, cost-effective technique and a reproducible process for both synthetic and natural polymers. It is found to be an attractive tool for various applications in biomedical engineering, filtration, protective clothing, catalysis reactions and sensors. Non-ionic cellulose ethers namely Ethyl Hydroxy Ethyl Cellulose (EHEC) is an important polysaccharide which is non-toxic, biocompatible and biodegradable and finds applications as thickening/rheology control agents in paints, cosmetics, detergents, oil recovery and also in the biomedical area. Poly (vinyl alcohol) (PVA) is a semi-crystalline hydrophilic polymer which is highly biocompatible and non-toxic having good thermal and mechanical properties and also high water solubility. Silver shows powerful antimicrobial activity and is non-toxic. It has been used to cure severe burns and chronic ulcers for many decades and is extensively used as an additive in various fields like prostheses, burn treatment, catheters, vascular grafts, dental resin components, ion exchange fibers, stainless steel materials, human skin and coating of medical devices. In the present work, EHEC/PVA nanofibers embedded with silver nanoparticles (AgNPs) are studied for their antibacterial activity using both gram positive and gram negative bacteria. The nanofibers show increase in tensile properties with the addition of silver nano-particles. The AgNPs embedded EHEC/PVA nanofiber mats having 0.5% AgNPs were found to enhance the wound healing with no scar formation in wistar rats. The biological in-vitro and in-vivo studies support the potential of EHEC based nanofibers as excellent bio-materials for the treatment of severe burns and wounds. To the best of our knowledge, this is the first report on the electrospinning of EHEC/PVA nanofibers for wound healing applications.

Fabrication of breathable superhydrophobic composite fabric with moisture permeability and weak-electric-field bactericidal ability designed for protective clothing applications

Most protective clothing on the market today cannot provide both comfort properties and protectability, which would not match the requirement for preventing or killing the rapidly growing and changing virus. Hence, a novel breathable and waterproof composite fabric used in protective clothing was designed through the hot-press process with three functional layers. The waterproof ability, moisture permeability, mechanical property, electricity and bactericidal ability of three layers and composite fabric were studied. Results showed that the moisture permeability of coated thermoplastic polyurethane (TPU) membrane reached 19854 g m2 d−1. The composite fabric had still excellent moisture permeability of up to 13956 g m2 d−1 and water contact angle of 151.7°. The coated TPU membrane had good tensile strength and acid resistance. The voltage and current of composite fabric after 7 days were approximately 0.336 V and 1.4 μA. The composite fabric had a 97.5 % filtering effect for NaCl aerosols, a 99 % bacteriostatic rate, and the ability to withstand the Phy-X174 phage with a diameter of 0.027 μm. This composite fabric based on the principle of moisture permeability and weak electric field could be used in protective clothing, which would be of theoretical significance and guiding practical production.

UV-assisted stabilization of superhydrophobic nanofibrous membranes for waterproof, breathable and thermal insulation applications

Polyacrylonitrile (PAN)/polyurethane (PU)/hydrophobic silicon dioxide (SiO2) nanofibrous membranes were prepared by electrospinning combined with a UV-induced stabilization method. The PAN/PU/SiO2 membranes possessed excellent self-cleaning performance because the introduction of SiO2 nanoparticles endowed the nanofibrous membranes with high surface roughness and good hydrophobicity. In addition, SiO2 nanoparticles could also promote the waterproof performance of nanofibrous membranes because hydrophobicity improved and pore size decreased with the increase of SiO2 content. Water vapor transmission rate of the membranes decreased from 10.8 to 9.2 kg m−2 d−1 with increasing of SiO2 concentration because SiO2 nanoparticles could fill the spaces among the adjacent nanofibers. Reflectance to sunlight of the PAN/PU/SiO2 membrane was much higher than that of the PAN/PU membrane, indicating an obvious radiative cooling effect due to loading of SiO2 nanoparticles. This facile fabrication of fluorine-free superhydrophobic membranes provides advantages for potential applications in self-cleaning materials and versatile protective clothing.

Advancements in Electrospun Nanofibrous Membranes for Improved Waterproofing and Breathability

AbstractElectrospun nanofibrous membranes have attracted significant interest due to their captivating waterproof and breathable characteristics, stemming from the presence of interconnected and hydrophobic channels within these enhanced textiles. These distinctive traits bestow upon them substantial potential across various domains, encompassing applications in medical dressings, masks, and protective clothing. However, they also give rise to concerns about their durability, compromised waterproofing performance, limited breathability, insufficient mechanical strength, and high production costs. Furthermore, the manufacturing processes of electrospun waterproof and breathable membranes (WBMs) may carry adverse environmental implications, necessitating improvements in sustainability and ecological compatibility. This study begins with a concise overview of the operational principles and criteria for performance evaluation relevant to electrospun WBMs, providing comprehensive guidelines to drive future research. Following this, the authors delve into a thorough exploration of typical fabrication techniques and the prevailing strategies, exemplified by noteworthy ongoing research initiatives. Last, the existing challenges are outlined to foster the development of WBMs. In addition, future research directions and perspectives are presented to expedite the advancement of WBMs and support their commercial implementation. It is anticipated that this comprehensive review will offer pragmatic recommendations for researchers dedicated to the advancement of WBMs.

TiO2 and Ag NPs modified polyacrylonitrile NFs: Antimicrobial, self-cleaning and SERS sensing capabilities for protective clothing applications

The COVID-19 outbreak has clearly shown that significant advances are required in protective clothing technology. This study presents fabrication of multifunctional polyacrylonitrile (PAN) nanofiber mats doped with titanium dioxide and Ag nanoparticles (Ag@PAN-TiO2 NFs). This multifunctional material exhibited antimicrobial properties, can self-clean under light due to its photocatalytic feature, and allows the detection of pollutants directly on NFs by surface-enhanced Raman scattering (SERS). The multi-functional mat showed a robust killing effect for E. coli and S. Aureus bacterial strains and bovine coronavirus. Additionally, the highly stable and reusable photocatalytic and self-cleaning activities of the mat were examined via the photocatalytic degradation of methylene blue (MB). The same molecule could be detected on the same platform at a concentration as low as 100 pM using SERS. This novel design integrated hotspot engineering with strategies to form multi-functional materials that emerge from antimicrobial, plasmonic, and photocatalytic properties.

Nanofibrous membranes with hydrophobic and thermoregulatory functions fabricated by coaxial electrospinning

AbstractIn the face of changing outdoor environments, it is necessary for us to develop advanced textiles with thermal regulation and hydrophobic properties. In order to create a fabric with both temperature control and waterproof properties, the study adjusted the ratio of polystyrene (PS) and polyvinylidene fluoride (PVDF) to produce nanofiber membranes with excellent morphology and dirt resistant properties. Furthermore, the hydrophobicity of the nanofibers was further improved by adding SiO2 to the spinning solution. Based on this, a core solution of octadecane (Oct) was used to give it thermal regulation functionality through coaxial electrospinning technique. The resulting composite nanofiber membrane exhibited excellent hydrophobicity and thermal regulation performance. The measurement results obtained from Differential Scanning Calorimetry (DSC) indicate that the maximum Oct encapsulation rate of the PS/PVDF/SiO2@Oct nanofiber membrane is 58.36%. The latent heat of the composite nanofiber membrane is 148.84 J/g, and the water contact angle (WCA) is 135°. The multifunctional composite nanofiber has great potential for applications in outdoor protective clothing and outdoor electronic device protection.

Reversible bacteria-killing and bacteria-releasing cotton fabric with anti-bacteria adhesion ability for potential sustainable protective clothing applications

Multifunctional antibacterial surfaces are playing an essential role in various areas. Smart antibacterial materials equipped with switchable “bacteria-killing” and “bacteria-releasing” abilities have been created by scientists. However, most of them are either biologically incompatible, or complex fabricating procedures, or cannot prevent themselves from being attached by bacteria. In this work, a double-layer smart antibacterial surface was created easily by simple surface initiate atom transfer radical polymerization: the upper layer PSBMA provides anti-bacteria adhesion capacity, the NCl bond can show bacteria-killing ability and the under layer PNIPAM can exhibit bacteria-releasing property. Remarkably, the NCl bond can interconvert with the NH bond easily, which allows switching between bacteria-killing and bacteria-releasing. As a result, the functional cotton fabrics can resist about 99.66 % of bacteria attaching, kill nearly 100 % of attached bacteria after 5 min contacting and release about 99.02 % of the formerly attached bacteria. Furthermore, the functional cotton fabric kept excellent anti-bacteria adhesion ability (about 99.27 %) and bacteria-releasing capacity (about 98.30 %) after 9 cycles of re-chlorination. In general, a reversible “bacteria-killing” and “bacteria-releasing” cotton fabric was fabricated with well anti-bacteria adhesion capacity in a simple way, and this smart multifunctional cotton fabric shows a great potential application in reusable protective clothing.

Design and characterization of polyurethane based electrospun systems modified with transition metals oxides for protective clothing applications

This paper reports the design and the fabrication of novel fiber membranes based on electrospun polyurethane (PU) fibers modified with copper and zinc oxide as potential systems for protective clothing. A one-step in-situ methodology is proposed to modify the PU systems. The modified PU membranes are widely characterized in terms of spectroscopic, morphological, thermal and barrier properties. Evaluation of surface charge and analysis of retention degree, obtained by testing four model systems (H2O, H2O/NaOH, lemon juice and sweat simulant), are even carried out. Then, to evaluate the protection against UV rays, weathering tests are accomplished while the carbonyl index gives a proof of the improved UV stability. The estimation of ultraviolet protection factor allowed to prove the total resistance to UV-A and UV-B rays. Finally, cytostatic effect against Gram+ and Gram- bacteria is evaluated. The reported results allow for stating that the designed materials show great potential as high-performance systems for protective clothing applications.

Synthesis and characterization of multi‐ionic block copolymers and blended membranes for chemical protective clothing applications

AbstractThis study discusses the synthesis of sulfonated amine block copolymers and the effect of multiple ionic domains and counter‐ion substitution on polymeric membranes' morphology and transport properties for chemical protective clothing (CPC) applications. The monomers 2‐(tert‐butylamino) ethyl methacrylate, 2‐ethoxy ethyl methacrylate, and styrene were used to prepare the block copolymers by atom transfer radical polymerization (ATRP). The copolymers were then sulfonated by chemical grafting with pendants sulfobutyl groups onto the polymer structure. Properties of the resulting membranes were evaluated as a function of block composition, incorporation of sulfonic groups, and counter‐ion substitution. Blended membranes with sulfonated poly(styrene‐isobutylene‐styrene) (SIBS) were also studied. A series of materials characterization techniques (e.g., Fourier‐transform infrared spectroscopy [FT‐IR], thermogravimetric analysis [TGA], atomic force microscopy [AFM], Small‐angle X‐ray scattering [SAXS]/wide‐angle X‐ray scattering [WAXS]) were performed to describe the changes to the membranes. The results indicate that synthesized copolymers lack phase segregation mainly because of a low sulfonation on the central amine block, leading the material to have a low Water/DMMP selectivity. As the sulfonated copolymers were blended with SIBS 75, the breathability of the membranes were enhanced 1.5 times, and almost all candidates achieved the water vapor transport rate limit of 1500 g m−2 day−1. Finally, the better‐found candidates for DMMP CPC were Mg2+ membranes, achieving selectivity between 20 and 90 range.

Electrospun Nanofibers Based on Polymer Blends with Tunable High-Performance Properties for Innovative Fire-Resistant Materials.

The main concern of materials designed for firefighting protective clothing applications is heat protection, which can be experienced from any uncomfortably hot objects or inner spaces, as well as direct contact with flame. While textile fibers are one of the most important components of clothing, there is a constant need for the development of innovative fire-retardant textile fibers with improved thermal characteristics. Lately, inherently fire-resistant fibers have become very popular to provide better protection for firefighters. In the current study, the electrospinning technique was applied as a versatile method to produce micro-/nano-scaled non-woven fibrous membranes based on various ratios of a poly(ether-ether-ketone) (PEEK) and a phosphorus-containing polyimide. Rheological measurements have been performed on solutions of certain ratios of these components in order to optimize the electrospinning process. FTIR spectroscopy and scanning electron microscopy were used to investigate the chemical structure and morphology of electrospun nanofiber membranes, while thermogravimetric analysis, heat transfer measurements and differential scanning calorimetry were used to determine their thermal properties. The water vapor sorption behavior and mechanical properties of the optimized electrospun nanofiber membranes were also evaluated.

Novel Antiviral and Antibacterial Durable Polyester Fabrics Printed with Selenium Nanoparticles (SeNPs).

The COVID-19 pandemic has clearly shown the importance of developing advanced protective equipment, and new antiviral fabrics for the protection and prevention of life-threatening viral diseases are needed. In this study, selenium nanoparticles (SeNPs) were combined with polyester fabrics using printing technique to obtain multifunctional properties, including combined antiviral and antibacterial activities as well as coloring. The properties of the printed polyester fabrics with SeNPs were estimated, including tensile strength and color fastness. Characterization of the SeNPs was carried out using TEM and SEM. The results of the analysis showed good uniformity and stability of the particles with sizes range from 40–60 nm and 40–80 nm for SeNPs 25 mM and 50 mM, respectively, as well as uniform coating of the SeNPs on the fabric. In addition, the SeNPs—printed polyester fabric exhibited high disinfection activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with an inhibition percentage of 87.5%. Moreover, a toxicity test of the resulting printed fabric revealed low cytotoxicity against the HFB4 cell line. In contrast, the treated fabric under study showed excellent killing potentiality against Gram-positive bacteria (Bacillus cereus) and Gram-negative bacteria (Pseudomonas aeruginosa, Salmonella typhi, and Escherichia coli). This multifunctional fabric has high potential for use in protective clothing applications by providing passive and active protection pathways.

Moisture barrier layer with supplemental chemical and biological protective functionality for firefighting clothing applications

One of the primary constituent layers of fire protective clothing is a flame-retardant, waterproof and breathable moisture barrier, which permits the outward transfer of perspiration from the firefighter’s body, while barring the inward entry of water. The introduction of a chemical and biological resistant functionality can greatly enhance the overall applicability of fire protective clothing. In the present work, a chemical & biological resistant waterproof breathable flame retardant moisture barrier fabric was prepared by laminating a biaxially stretched microporous expanded polytetraflouroethylene (ePTFE) membrane with Activated Carbon Fabric using a hot melt reactive breathable polyurethane adhesive. The developed laminate was found to exhibit an excellent balance of waterproofness (23 kPa) and breathability, which was quantified in terms of water vapour transmission rate (WVTR) and water vapour resistance (Ret). High values of WVTR, 1.1025 × 104 ± 9.8×101 g/m2/day complimented with exceptionally low values of Ret, 2.9 m2Pa/W are indicative of its high degree of breathability. Vertical flammability tests clearly revealed the exceptional flame resistance offered by the laminate, where after-flame, after-glow or melt-dripping was not observed and the char length was ∼4.2 cm. Further, the laminate exhibited requisite degree of protection against biological and chemical warfare (CW) agent with no breakthrough of the CW agent being perceived within the time frame of 24 h. The excellent combination of flame retardancy, breathability, waterproofness, chemical and biological protection, bestows the laminate excellent potential for usage as moisture barrier in fire protective clothing applications.

Design and Characterization of Polyurethane Based Electrospun Systems Modified with Transition Metals Oxides for Protective Clothing Applications

Design and Characterization of Polyurethane Based Electrospun Systems Modified with Transition Metals Oxides for Protective Clothing Applications

Sulfonated poly(styrene‐isobutylene‐styrene) grafted with hexyl‐ and butyl‐imidazolium chloride ionic liquids

AbstractIn this work, novel sulfonated poly(ionic liquid)s block‐copolymers based on poly(styrene–isobutylene–styrene) (SIBS) are synthesized for chemical protective clothing (CPC) applications. The synthesis consists of the chloromethylation of SIBS, followed by the incorporation of N‐alkylimidazole through chemical grafting, and concluding with sulfonation of the resulting compound. Properties of the membranes are determined as a function of different N‐alkylimidazoles (butylimidazole and hexylimidazole) and sulfonation levels (7–23 mol%). Results show that the incorporation of imidazole and sulfonic groups increases the thermal stability of SIBS as well as its water absorption capabilities. The interaction between the ionic moieties in the polymeric matrix allows the formation of hydrophilic nanochannels, which promote the transport of permeants through the membrane. The high water vapor transmission rate (above 2000 g m−2 day−1) and values of selectivity (~50) demonstrate that the breathability of the synthesized membrane is improved while blocking the passage of dimethyl methylphosphonate (simulant of agent Sarin). The above mentioned observations suggest that sulfonated SIBS‐PIL's membranes are potential materials for CPC applications.

Development of high-insulating materials with aerogel for protective clothing applications – an overview

AbstractAerogels are ultra-light solids with extremely low thermal conductivity (even lower than air), thanks to which they have a huge potential in a wide range of applications. The purpose of this publication is to present the state-of-the art knowledge of the possibility of using aerogels to increase the thermal insulation properties of clothing materials intended for use in both cold and hot environments. Various methods of aerogels application to textile materials (non-woven, woven and knitted fabrics) are discussed, indicating their advantages and limitations. Numerous research studies confirm that aerogels significantly improve the thermal insulation properties of materials, but due to their delicate and brittle structure and their tendency to dusting, their application still poses considerable problems.

Stretchable, mechanically resilient, and high electromagnetic shielding polymer/MXene nanocomposites

AbstractThe increasingly disturbing electromagnetic wave pollution has intensified research for high‐performance shielding materials to protect humans and the environment. It remains a great challenge to combine high electromagnetic interference (EMI) shielding performance with mechanical robustness and stretchability. These crucial features have been simultaneously achieved in this work by using a facile method to prepare elastomer/MXene nanocomposites. An EMI shielding effectiveness of 49 dB was obtained from a 1‐mm thick nanocomposite film at 19.6 vol% of MXene; the film has a density of 1.25 g/cm3. The outstanding electrical conductivity of MXene – 4350 ± 125 S·cm−1 – provided free charge carriers in the matrix to absorb electromagnetic signals, leading to the dominance of absorption mechanism over reflection mechanism. Owing to a nanofiller modification step, the nanocomposite films demonstrated not only outstanding EMI shielding but sufficient strength and stretchability. A nanocomposite at 14.0 vol% exhibited Young's modulus of 15.85 ± 0.75 MPa and tensile strength 25.94 ± 0.81 MPa with elongation at break of 170 ± 5.6%, which relates to high stretchability. These impressive properties make our nanocomposites suitable for use in harsh environments as well as applications in stretchable devices, protective clothing, aerospace, aircraft, and automotive industries.

Antibacterial, Antiviral, and Self-Cleaning Mats with Sensing Capabilities Based on Electrospun Nanofibers Decorated with ZnO Nanorods and Ag Nanoparticles for Protective Clothing Applications.

The COVID-19 pandemic has clearly shown the importance of developments in fabrication of advanced protective equipment. This study investigates the potential of using multifunctional electrospun poly(methyl methacrylate) (PMMA) nanofibers decorated with ZnO nanorods and Ag nanoparticles (PMMA/ZnO-Ag NFs) in protective mats. Herein, the PMMA/ZnO-Ag NFs with an average diameter of 450 nm were simply prepared on a nonwoven fabric by directly electrospinning from solutions containing PMMA, ZnO nanorods, and Ag nanoparticles. The novel material showed high performance with four functionalities (i) antibacterial agent for killing of Gram-negative and Gram-positive bacteria, (ii) antiviral agent for inhibition of corona and influenza viruses, (iii) photocatalyst for degradation of organic pollutants, enabling a self-cleaning protective mat, and (iv) reusable surface-enhanced Raman scattering substrate for quantitative analysis of trace pollutants on the nanofiber. This multi-functional material has high potential for use in protective clothing applications by providing passive and active protection pathways together with sensing capabilities.

Green-Solvent-Processed Fibrous Membranes with Water/Oil/Dust-Resistant and Breathable Performances for Protective Textiles.

Waterproof and breathable membranes (WBMs) are highly demanded worldwide due to their promising applications in outdoor protective clothing, medical hygiene, and electronic devices. However, the design of such materials integrated with environmental friendliness and high functionality has been considered a long-standing challenge. Herein, we report the green-solvent-processed polyamide fibrous membranes with amphiphobicity and bonding structure via ethanol-based electrospinning and water-based impregnating techniques, endowing the fibrous membranes with outstanding water/oil/dust-resistant and good breathable properties. The developed green smart fibrous membranes exhibit integrated properties with robust water and oil intrusion pressures of 101.2 and 32.4 kPa, respectively, excellent dust removal efficiency of above 99.9%, good water vapor transmission rate of 11.2 kg m-2 d-1, air permeability of 2.6 mm s-1, tensile strength of 15.6 MPa, and strong toughness of 22.8 MJ m-3, enabling the membranes to protect human beings and electronic devices effectively. This work may shed light on designing the next generation green smart fibrous WBMs for protective textiles.

Enhancing the mechanical features of poly(vinyl) alcohol nanofibers with the addition of boron nitride

Improvement of nano-sized products with boron additives with remarkable properties has become a popular trend for many different application areas. Here, we have reported an efficient poly(vinyl alcohol) (PVA) based composite nanofiber which was functionalized with the hexagonal boron nitride (h-BN) via electrospinning technique, for the first time as far as known, for body-armor and protective clothing applications. PVA-based composite nanofibers containing h-BN with a diameter of approximately 326 nm have shown significant mechanical features compared to pure PVA nanofibers with a diameter of about 223 nm. Mechanical features were investigated by nanoindentation and the results of nanoindentation demonstrated that the elastic modulus of PVA nanofibers increased by 77%, and hardness values of polymeric nanofibers reached ten times more, by the addition of h-BN. FTIR and XRD characterizations approved that there is no chemical change of h-BN when it was integrated into the PVA based composite nanofibers. We exceptionally believe that the achieved results offer a potential lightness and cost-effective strategy for body armor and protective clothing applications in contrast to boron carbide-based body armor products, which have main problems such as weightiness and high-priced.

Microwave-assisted in-situ incorporation of nanostructured HyWO3-x on cotton cellulose for enhanced ultraviolet shielding applications

Nanostructured materials modified cotton cellulose could be a versatile and cost-effective solution for developing wide range of protective fabrics. In this background, cotton cellulose was surface modified with hydrated form of non-stoichiometric tungsten oxide (HyWO3-x) using microwave reduction technique for the development of UV radiation blocking and thermo-chromic fabrics. Herein, the surface modification and characterization of cotton cellulose having ligand to metal charge transfer (LMCT) transition via reduction process with enhanced UV blocking features are presented. X-ray diffraction patterns confirmed the poly-crystalline and amorphous nature of unmodified and surface modified cotton fabrics. Scanning electron micrographs revealed the growth of nanostructured HyWO3-x on cotton cellulose and surface analysis showed the existence of tungsten, carbon, oxygen elements. Differential scanning calorimetry of treated fabric exhibited a change of exothermic behavior from endothermic at the characteristic onset temperature. Thermogravimetric analysis revealed the least weight loss up to 600°C of the surface treated cotton cellulose. Further, Ultraviolet Protection Factor (UPF) of the modified fabric was measured using an in-vitro method following the AATCC 183:2004 standard employing UV transmittance analyzer. The UPF was estimated to be 2000, which is excellent for protective clothing applications according to UPF standard for fabrics. Also, the ligand to metal charge transfer characteristics of WO3-x modified cotton cellulose revealed the selective transition towards microwave irradiation at different reduction power.