Electrospun waterproof breathable membrane with a high level of aerosol filtration

In this study, several nanofibrous polyurethane (PU) webs were electrospun (ES) by changing different effective parameters (e.g., polymeric concentration, voltage, feed flow, etc.). The physical–chemical properties of the webs (i.e., average fiber diameters, thickness, areal density, porosity, contact angle, waterproofness, air permeability (AP), water vapor transmittance, and aerosol filtration) were studied based on the standard test methods. A commercially available waterproof breathable (WPB) fabric was used as a reference for benchmarking. The beads‐free webs with an average fiber diameter as small as 200 nm were achieved from electrospinning of 10 wt % PU in N,N‐dimethylformamide, at feed rate of 0.5 mL/h, applied voltage of 25 kV, and tip‐to‐collector distance of 15 cm. By optimizing the electrospinning parameters, a web with a high level of waterproofness, high AP, and high water vapor transmission rate (WVTR) was obtained. In addition, the selected ES membrane showed very promising aerosol filtration efficiency with complete removal of particles larger than 0.5 µm, and 94% reduction in the concentration of smaller particles. We found a linear empirical equation for the estimation of AP and WVTR based on the average pore size diameter, the membrane thickness, and the porosity with very high regression coefficients (R² > 0.97). © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45660.     

Preparation of waterborne polyurethanes using an amphiphilic diol for breathable waterproof textile coatings

The application of polyurethanes (PUs) on breathable waterproof fabric coatings requires a balance of water vapor permeability (WVP) and water resistance which can be achieved by tailoring hydrophilic and hydrophobic segments. PU prepolymers were prepared from isophorone diisocyanate, dimethylol butanoic acid, and a mixture of various ratios of amphiphilic PPG2050 (copolymer of ethylene oxide and propylene oxide with –OH end groups) and hydrophobic poly(tetramethylene ether glycol) (PTMEG). After neutralization with triethylamine, the prepolymers were chain-extended with ethylene diamine/1,4-butanediol (1:1 by molar). The WVP values of the fabric coatings prepared using various waterborne PUs were very similar (910–990 g/m² × 24 h). When waterborne PUs prepared using a mixture of PPG2050 and PTMEG were employed for the textile coatings, the resulting PU-coated textiles exhibited excellent waterproof properties (>10,000 mm H₂O). The textile coatings prepared from PPG2050/PTMEG-based waterborne PUs were significantly more waterproof than those prepared from poly(ethylene glycol) (PEG)/poly(propylene glycol) (PPG)/PTMEG-based waterborne PU. This is probably due to a more even distribution of hydrophobic segments in the PUs, even though the WVP values of the PEG/PPG/PTMEG-based PU coatings were considerably smaller than those of the PPG2050/PTMEG-based PU coatings.     

Breathable properties of m‐Aramid nanofibrous membrane with high thermal resistance

Electrospinning of m‐aramid in dimethyl acetamide/LiCl solution was investigated to develop thermo‐resistant nanofibrous membranes for breathable waterproof materials. The m‐aramid nanofibers were continuously generated and densely mounted to the membrane without the blockage of the spinning tip during electrospinning. In order to obtain the electrospun m‐aramid nanofibers with different fiber diameters, the polymer concentration in the solution and the spinning distance were varied. Electrospun m‐aramid nanofibrous membranes of various fiber diameters and thicknesses were prepared, and then compared with two commercial expanded polytetrafluoroethylene (ePTFE) membranes with respect to water vapor permeability and pore size. The m‐aramid nanofibrous membrane showed a good water vapor permeability that satisfied the criterion of a breathable membrane, higher than those of the ePTFE porous membranes. Therefore, m‐aramid nanofibrous membrane with thermal and mechanical resistance has great potential for breathable waterproof materials and filters. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41515.     

Preparation of waterborne polyurethanes using an amphiphilic diol for breathable waterproof textile coatings

The application of polyurethanes (PUs) on breathable waterproof fabric coatings requires a balance of water vapor permeability (WVP) and water resistance which can be achieved by tailoring hydrophilic and hydrophobic segments. PU prepolymers were prepared from isophorone diisocyanate, dimethylol butanoic acid, and a mixture of various ratios of amphiphilic PPG2050 (copolymer of ethylene oxide and propylene oxide with –OH end groups) and hydrophobic poly(tetramethylene ether glycol) (PTMEG). After neutralization with triethylamine, the prepolymers were chain-extended with ethylene diamine/1,4-butanediol (1:1 by molar). The WVP values of the fabric coatings prepared using various waterborne PUs were very similar (910–990 g/m² × 24 h). When waterborne PUs prepared using a mixture of PPG2050 and PTMEG were employed for the textile coatings, the resulting PU-coated textiles exhibited excellent waterproof properties (>10,000 mm H₂O). The textile coatings prepared from PPG2050/PTMEG-based waterborne PUs were significantly more waterproof than those prepared from poly(ethylene glycol) (PEG)/poly(propylene glycol) (PPG)/PTMEG-based waterborne PU. This is probably due to a more even distribution of hydrophobic segments in the PUs, even though the WVP values of the PEG/PPG/PTMEG-based PU coatings were considerably smaller than those of the PPG2050/PTMEG-based PU coatings.     

Polydimethylsiloxane‐modified polyurethane–poly(ɛ‐caprolactone) nanofibrous membranes for waterproof,breathable applications

In this study, we prepared polydimethylsiloxane (PDMS)‐modified polyurethane–poly(?‐caprolactone) nanofibrous membranes with excellent waterproof, breathable performances via an electrospinning technique. Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis, and mechanical testing were used to characterize the morphologies and properties of the composite nanofibers. The fiber diameter and porous structure of the membranes were regulated by the adjustment of the temperatures of thermal treatment and the PDMS concentrations. The fibrous membranes obtained at a typical temperature of 70 °C possessed an optimized fibrous structure with a diameter of 514 ± 2 nm, a pore size of 0.55–0.65 µm, and a porosity of 77.7%. The resulting nanofibrous membranes modified with 5 wt % PDMS were endowed with good waterproof properties (water contact angle = 141 ± 1°, hydrostatic pressure = 73.6 kPa) and a high breathability (air permeability rate = 6.57 L m^?2 s^?1, water vapor transmission rate = 9.03 kg m^?2 day^?1). Meanwhile, the membranes exhibited robust mechanical properties with a high strength (breakage stress = 11.7 MPa) and excellent thermal stability. This suggests that they would be promising candidates for waterproof, breathable applications. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46360.     

A waterproof and breathable nanofibrous membrane with thermal-regulated property for multifunctional textile application

In this work, a waterproof and breathable nanofibrous membrane with thermal-regulated performance and exhibits excellent mechanical property is fabricated by coaxial electrospinning. The fiber shell is consisted of polyvinylidene fluoride (PVDF) and polyvinyl butyral (PVB), and the core is octadecane. First, well-performed waterproof and breathable membranes are obtained by optimizing its morphology and pore structure. Then octadecane is loaded into the fibers in the form of core by coaxial electrospinning, though it gives the membranes a thermal regulating function, but the drawback is the sacrifice of overall properties. Thus, carbon nanotubes are loaded into the shell and studied, finally, the best membrane has a comprehensive performance with hydrostatic pressure of 59.2 kPa, water vapor transmission rate (WVTR) of 7.846 kg m⁻² d⁻¹, latent heat of 50.1 J g⁻¹, as well as excellent tensile strength of 20.2 MPa, which shows its certain reference significance to the synthesis of multifunctional membrane.     

Application of polyurethane/citric acid/silicone softener composite on cotton/polyester knitted fabric producing durable soft and smooth surface

Application of softeners on fabrics can usually increase the fabric pilling tendency and it is difficult to obtain a soft handle fabric without pilling during wearing. This research was conducted to use various chemicals to reduce pilling with reasonable softness on the cotton/polyester knitted fabric. Diverse composites of the water‐based polyurethane resin (PU), citric acid (CA) as a crosslinking agent and silicone‐based softener were selected and applied on the fabric through conventional pad‐dry‐cure method. The characteristics of the treated fabrics including pilling rate, pilling density, water droplet adsorption time, bending length, crease recovery angle, tensile strength, and water contact angle were examined and reported. Application of the polyurethane resin along with citric acid reduced the fabric pilling. However, co‐application of resin, CA, and softener improved the fabric crease recovery angle, bending length, and water droplet adsorption time. The preferred formulation was 20 g L^?1 CA, 25 g L^?1PU resin, and 20 g L^?1 silicone softener. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and properties of highly hydrophilic waterborne polyurethane‐ureas containing various hardener content for waterproof breathable fabrics

As part of an ongoing search for highly hydrophilic waterborne polyurethanes for waterproof breathable fabrics, a waterborne polyurethane [waterborne polyurethane‐ureas (WBPU): P70, the number indicates the poly(ethylene glycol) (PEG) content] dispersion was synthesized from PEG (70 wt %) and dimethylol propionic acid (14 mol %) as the hydrophilic/ionic components, 4,4′‐diisocyanato dicyclohexylmethane as a diisocyanate, ethylenediamine as a chain extender, and aliphatic tri‐isocyanate as a hardener. To determine the best highly hydrophilic WBPU coatings for waterproof breathable fabrics, this study focused on the effect of the hardener content(0–1.2 wt %) in the WBPU P70 sample on the dynamic thermal mechanical properties, contact angle/surface energy, water swelling, water insolubility, and water vapor transmission rate (WVTR). The contact angle, water swelling, glass transition temperature, modulus, and strength increased with increasing hardener content, whereas the surface energy, water insolubility, and WVTR decreased. Sample P70/0.5 (cured sample containing 0.5 wt % of hardener) showed relatively good dimensional stability in water (high water insolubility), strong hydrophilicity (low‐water contact angle/high‐surface energy/high water absorption), and a high WVTR, highlighting its promising applications in waterproof breathable fabrics. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Cocontinuous cellulose acetate/polyurethane composite nanofiber fabricated through electrospinning

Cocontinuous cellulose acetate (CA)/polyurethane (PU) composite nanofibers were obtained through electrospinning of partially miscible CA and PU in 2:1 N,N‐dimethylacetamide (DMAc)/acetone mixture solvent. Their structures, mechanical, and thermal properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and differential scanning calorimetry (DSC). The structures and morphologies of the nanofibers were affected by component ratio in the binary mixtures. PU component not only facilitated the electrospinning of CA at CA concentration down to 12 wt%, but reinforced the tensile strength of CA/PU nanofibrous mats, while semirigid component CA in the composite nanofibers could greatly improve the rigidity and dimensional stability of CA/PU nanofibrous mats. In a series of nanofibrous mats with varied CA/PU composition ratios, CA/PU 20/80 showed excellent tensile strength and Young's modulus. The residual product after selective removal of any one of the components in CA/PU composite nanofibers by washing with proper solvent maintained the fiber structure but greatly reduced the fiber size, suggesting CA/PU composite fibers showed a cocontinuous nanofiber structure due to phase separation in the spinning solution and in the course of electrospinning. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers     

Fabrication and characterization of polyurethane electrospun nanofiber membranes for protective clothing applications

Electrospun nanofibrous webs are important in nanotechnology applications due to their high surface area and interconnected porosity. In this study, the effect of electrospinning duration on some physical and mechanical properties of polyurethane (PU) electrospun webs is investigated for potential applications such as protective clothing and membranes. The results show that the thickness and weight of webs and subsequently their tensile strength increase linearly with the electrospinning duration. Air permeability of nanofibrous webs decrease and hydrostatic pressure increases nonlinearly while water vapor permeability remains constant. This work shows that air permeability of PU webs follows Fick's law of diffusion. Some regression models have been proposed to describe electrospun membranes behavior. The results of this investigation indicate that this new generation of nanofibrous materials has a good potential for application as membrane in protective clothing. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Reversible photochromic nanofibrous membranes with excellent water/windproof and breathable performance

Electrospun nanofibrous membranes (NFMs) with outstanding photochromic property, waterproof, and breathability have attracted considerable interest owing to their multifunctional applications in intelligent clothing, self‐cleaning, and protection. However, great challenges still remain in creating such functional materials. A novel waterproof–breathable membrane with robust photochromic property is fabricated by introducing photochromic microcapsule (PM) into electrospun thermoplastic polyurethanes (TPU) membranes. Compared with the pristine TPU NFMs, the composite TPU/PM membranes are endowed with reversible photochromic properties. In addition, the composite membranes not only exhibited a water contact angle of 137° and a milk contact angle of 130°, but also had integrated properties of modest water vapor transmittance rate of 19,278 g m^?2 day^?1, high air permeability of 962 mm s^?1, low waterproofness of 2.813 kPa, and comparable tensile strength of 12.08 MPa. Furthermore, the convenience and efficiency of this fabrication process will allow for large‐scale production of the multifunctional NFMs. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46342.     

Printing of reactive silicones for surface modification of textile material

For outdoor sports, waterproof breathable materials are widely used to provide protection from environmental factors like rain and wind. The most important techniques to achieve excellent performance use perfluorinated organic substances, which must be replaced in the near future due to health concerns and their environmental persistency. Printing of textile materials with reactive silicone pastes could be an alternative to introduce water repellency without fluorocarbon finishing. In this work, production of barrier textiles through one‐step silicon printing was studied, using a two‐component paste with long pot life and a thermal fixation step. Three different knitted fabrics made from micromodal, polyamide/elastin, and cotton/polyester were used as substrates for the printing. The achieved hydrophobic modification of the fabric was analyzed by determination of water shedding angle, water resistance, water retention values, moisture content, air permeability, tensile properties, and infrared spectroscopy. The results indicate several areas of technical application for the modified fabric, such as barrier textiles with permeability control, localized modification of mechanical properties of fabric and garment. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42594.     

智能防水透湿聚氨酯研究进展

简要介绍了实现形状记忆聚氨酯(SMPU)的智能透湿机理,综述了SMPU在智能透湿性方面的研究进展及智能防水透湿膜和织物研究中存在的问题,提出了研究开发具有创新功能的智能防水透湿织物是未来纺织工业发展的趋势。     

Tri-Layer Laminated Fabric-Induced Sweating Surfaces for Passive Cooling

Fabrics which can keep people cool in a hot climate have attracted considerable attention in recent years. Among various cooling strategies, fabric cooling by water evaporation is proved to be very safe, simple and sustainable. Here, a tri-layer laminated fabric (TLF) inspired by perspiration is designed to realize passive cooling of human body. An interlayer fabric which is coated with crosslinked sodium polyacrylate can absorb and store a large amount of water. A moisture-absorbing and quick-drying fabric is used as the outer layer while a waterproof breathable fabric is used on the inside of the laminate in contact with skin. The prepared TLF shows decent evaporative cooling performance under dry heat conditions. The water absorbency of TLF is about 400% higher than that of pristine cotton after 1 h soaking in water. Under a 1 sun irradiation (1000 W m⁻²), the indoor temperature of a simulated room can be reduced by ≈5–7 °C compared with the other without a cooling system. Meanwhile, the evaporative cooling effect can be maintained up to 5 h. This cooling fabric shows broad application prospects in the fields of thermal cooling to human and buildings.     

Sea‐island polyurethane/polycarbonate composite nanofiber fabricated through electrospinning

Sea‐island polyurethane (PU)/polycarbonate (PC) composite nanofibers were obtained through electrospinning of partially miscible PU and PC in 3 : 7 (v/v) N,N‐dimethylformamide (DMF) and tetrahydrofuran (THF) mixture solvent. Their structures, mechanical, and thermal properties were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, thermogravimetric (TG), and differential scanning calorimetry (DSC). The structures and morphologies of the nanofibers were influenced by composition ratio in the binary mixtures. The pure PC nanofiber was brittle and easy to break. With increasing the PU content in the PU/PC composite nanofibers, PU component not only facilitated the electrospinning of PC but improved the mechanical properties of PU/PC nanofibrous mats. In a series of nanofibrous mats with varied PU/PC composition ratios, PU/PC 70/30 showed excellent tensile strength of 9.60 Mpa and Young's modulus of 55 Mpa. After selective removal of PC component in PU/PC composite nanofibers by washing with acetone, the residual PU maintained fiber morphology. However, the residual PU nanofiber became irregular and contained elongated indents and ridges along the fiber surface. PU/PC composite fibers showed sea‐island nanofiber structure due to phase separation in the spinning solution and in the course of electrospinning. At PC content below 30%, the PC domains were small and evenly dispersed in the composite nanofibers. As PC content was over 50%, the PC phases became large elongated aggregates dispersed in the composite nanofibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Preparation of poly(NaSS‐co‐HEMA) self‐supporting nanofiltration membrane with high cationic permselectivity by electrospinning

A crosslinked nanofibrous cation exchange membrane with high ion permeability and robust mechanical properties was fabricated by electrospinning. Copolymer, poly(sodium styrene sulfonate‐co‐2‐hydroxyethyl methacrylate), was selected as the electrospun material. Fourier transform infrared spectroscopy, ¹H‐nuclear magnetic resonance, and scanning electron microscopy were employed to characterize the copolymer and nanofibrous mat. After a series of preliminary experiments, the proper solvents and their ratio, H₂O/tetrahydrofuran/N,N′‐dimethylformamide (2/1/3 vol/vol/vol), was selected and the electrospinning optimal parameters were determined by orthogonal experiments. Formaldehyde vapor was employed to crosslink the mat. It was observed that the water sorption decreased from 47.9% to 18.4% as the crosslinking time increased from 20 to 32 h. The robust mat with the high tensile strength of 4.85 MPa and 40% elongation at break was obtained at 28 h. The permselectivities of Na⁺, K⁺, and Ca²⁺ were 89%, 85%, and 81%, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45541.     

新型纤维材料及其制品在体育用品中的应用

以推动新型纤维材料及其制品在体育用品领域的开发和应用着手,从纤维的物理和化学性能、制作工艺、后整理加工等方面对各类新型纤维材料,如碳纤维、Outlast纤维、对位芳纶、吸湿排汗功能性纤维、负离子功能性纤维以及新型纤维织物如防水透湿织物、低阻抗力的运动织物、超高强力织物等在体育用品中的广泛应用进行了介绍。     

Multifunctionality of poly(vinyl alcohol) nanofiber webs containing titanium dioxide

We prepared titanium dioxide/PVA nanocomposite fiber webs for application in multifunctional textiles by electrospinning. The morphological properties of the TiO₂/PVA nanocomposite fibers were characterized using scanning electron microscopy and transmission electron microscopy. Layered fabric systems with electrospun TiO₂ nanocomposite fiber webs were developed using various concentrations of TiO₂ and a range of web area densities, and then the UV‐protective properties, antibacterial functions, formaldehyde decomposition ability, and ammonia deodorization efficiency of the fabric systems were assessed. Layered fabric systems with TiO₂ nanocomposite fiber webs containing 2 wt% TiO₂ nanoparticles at 3.0 g m^?2 web area density exhibited an ultraviolet protection factor of greater than 50, indicating excellent UV protection. The same system showed a 99.3% reduction in Staphylococcus aureus. Layered fabric systems with TiO₂ nanocomposite fiber webs containing 3 wt % TiO₂ nanoparticles at 3.0 g m^?2 web area density exhibited a 85.3% reduction in Klebsiella pneumoniae. Titanium dioxide nanocomposite fiber webs containing 3 wt % TiO₂ nanoparticles at 3.0 g m^?2 web area density exhibited a formaldehyde decomposition efficiency of 40% after 2 h, 60% after 4 h, and 80% after 15 h under UV irradiation. The same system showed an ammonia deodorization efficiency of 32.2% under UV irradiation for 2 h. These results demonstrate that TiO₂ nanocomposite fibers can be used to produce advanced textile materials with multifunctional properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Developing protective textile materials as barriers to liquid penetration using melt‐electrospinning

Electrospun polypropylene fiber webs and laminates were developed using melt‐electrospinning, to explore an alternative way of manufacturing protective clothing materials for agricultural workers. Electrospun polypropylene webs were fabricated in two levels of thickness. To examine the effect of lamination on the protection/thermal comfort properties, the webs were laminated on nonwoven fabric substrates. Barrier performance was evaluated for the electrospun webs and laminates, using two pesticide mixtures that represent a range of surface tension and viscosity. Effects of web thickness and lamination on air permeability and water vapor transmission were assessed as indications of thermal comfort performance. Penetration testing shows that electrospun polypropylene webs provide excellent barrier performance against the high surface tension challenge liquid, whereas the laminated fabrics of electrospun polypropylene webs exhibited performance of 90–100% for challenge liquids with varying surface tension. Air permeability of electrospun polypropylene webs decreased by ～20% because of the lamination and web thickness, but was still higher than most of the materials currently in use for protective clothing. Water vapor transmission of electrospun polypropylene webs reduced by up to 12% from the lamination and web thickness as well, but was still in a range comparable to woven work clothing fabrics. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3430–3437, 2006     

Effect of nanocrystalline cellulose addition on needleless alternating current electrospinning and properties of nanofibrous polyacrylonitrile meshes

Needleless alternating current (AC)‐electrospinning is capable of achieving high nanofiber generation rates while adding more flexibility to the process development when compared to common direct current (DC)‐electrospinning. However, AC‐electrospinning process may produce very different results than DC‐electrospinning when using the same precursors. This study demonstrated that stable AC‐electrospinning of uniform and mechanically strong polyacrylonitrile (PAN) nanofibrous meshes can be achieved at 30 ± 5 kV rms voltage when 0.75–6.0 wt % of nanocrystalline cellulose‐II with respect to PAN is added to a typical PAN precursor solution. Efficient generation (up to 2 g/h rate or 0.7 g h^?1 cm^?2 mass flux) of nanofibers with 250–500 nm fiber diameters has been observed when using flat fiber‐generating electrodes with diameters up to 25 mm. Depending on the amount of nanocellulose, nanofibrous nanocellulose/PAN meshes revealed large variations in tensile modulus (90–273 MPa) and yield strength (1.0–2.5 MPa), whereas the fiber diameter, air permeability, air resistance, mesh porosity, and water absorption were less affected. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45772.