Preparation and properties of waterborne polyurethane‐urea/sodium alginate blends for high water vapor permeable coating materials

To improve the water vapor permeability of coating materials, aqueous sodium alginate (SA) solution was blended with waterborne polyurethane‐urea (WBPU) dispersions synthesized by prepolymer mixing process. The content of SA for stable WBPU/SA dispersions was found to be below 30 wt %. As the SA content increased, the number and density of total micropores (tunnel‐like micropores/isolated micropores) formed after dissolution of SA in water increased, and the water vapor permeability of coated Nylon fabric also increased remarkably. These results clearly demonstrate that utilizing WBPU/water soluble polymer SA blends as coating materials and then dissolving SA in water surely facilitate obtaining prominent breathable fabrics. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Preparation and properties of microencapsulated octadecane with waterborne polyurethane

A series of microencapsulated blends of waterborne polyurethane (WBPU) as a matrix polymer and phase change material octadecane as a domain material were prepared in the presence of emulsifier. Nylon fabrics were coated with the coating materials formulated from microencapsulated blends, thickener, and hardener. The morphology and thermal behaviors of microencapsulated octadecane and WBPU/octadecane‐coated nylon fabrics were investigated using SEM, DSC, and KES‐F7. The size of octadecane microspheres increased with increasing octadecane contents. However, the size of microcsphere (1–6 μm) decreased with increasing emulsifier contents. ΔH_fusion, ΔH_{crystallization}, and their filling efficiencies of octadecane in film samples were found to increase with increasing microencapsulated blends, thickener, and hardener contents. Especially, thickener and hardener could function in trapping microencapsulated octadecane. Thermal characteristic Q_max (J/cm² s) values of WBPU/octadecane‐coated nylon fabrics are much higher than those of the control nylon fabric and WBPU‐coated nylon fabrics, indicating that the nylon fabrics coated with WBPU/octadecane blends have cooler touch sensation compared with nylon fabrics and WBPU‐coated nylon fabrics. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1596–1604, 2005     

Effect of polyisocyanate hardener on adhesive force of waterborne polyurethane adhesives

A series of waterborne polyurethane (WBPU)/hardener adhesives were obtained from mixing of WBPU containing different types of polyol as a soft segment with aliphatic and aromatic polyisocyanates hardeners. By characterization of allophanate and biuret bonds formed from the reaction of hardener NCO with urethane/urea groups of WBPU using ¹HNMR spectroscopy. It was found that the optimum number ratio (molar ratio) of NCO group of hardener to urethane/urea group of WBPU that shows the highest adhesion force was depended on the type of hardener (aliphatic/aromatic polyisocyanate) and dimethylol propionic acid (DMPA) content (total content of urethane/urea groups); however independent of the type of soft segment (polyol) of WBPU. The optimum number ratio (molar ratio) of NCO group of aromatic polyisocyanate hardener to urethane/urea was higher than that of aliphatic hardener to achieve the highest adhesion force of WBPU. The adhesive force increased with increasing hardener content up to the optimum point and then decreased. Poly(tetramethylene adipate glycol) (PTAd) based WBPUs with aliphatic hardener show higher adhesive force than Poly(tetramethylene oxide glycol) (PTMG) and aliphatic hardener‐based WBPUs at the optimum number ratio (molar ratio) of NCO group of hardener to urethane/urea group of WBPU. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 3663–3669, 2007     

Preparation and characterization of waterborne polyurethane/clay nanocomposite: Effect on water vapor permeability

A series of waterborne polyurethane (WBPU)/clay nanocomposite coating materials were prepared by prepolymer process with different clay contents (0–2 wt %). The study investigated surface structure as well as water resistance, thermal, mechanical, and water vapor permeability (WVP) of composite materials as a function of clay contents. The glass transition temperature of composite materials was higher than pristine WBPU and also increased with increasing clay contents. Thermal stability, and water resistance of the nanocomposite films also increased, when compared with pristine WBPU, and these properties increased with an increase in clay content. The maximum tensile strength was found with optimum clay content (1 wt %) of composite films. The WVP of coated nylon fabrics depend on the clay content and temperatures. The rate (%) of WVP of coated nylon fabrics decreased with increasing clay content at a fixed temperature. However, at a fixed clay content the WVP increased with the increase of temperatures. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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.     

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。     

Characteristics of waterborne polyurethane/poly(N‐vinylpyrrolidone) composite films for wound‐healing dressings

For ideal wound‐healing dressings, a series of waterborne polyurethane (WBPU)/poly(N‐vinylpyrrolidone) (PVP) composite films (transparent film dressings) were prepared by in situ polymerization in an aqueous medium. Stable WBPU/PVP composites, which had a high remaining weight greater than 98.4%, were obtained. The maximum content of PVP for stable WBPU/PVP dispersions was found to be about 15 wt %. The water absorption (%) and equilibrium water content (%) of the WBPU/PVP composite films remarkably increased in proportion to the PVP content and the time of water immersion. The maximum water absorption and equilibrium water content of the WBPU/PVP composite films were in the range of 21–158 and 22–56%, respectively. The water vapor transmission rate of the WBPU/PVP composite films was in the range of 1816–2728 g/m²/day. These results suggest that WBPU/PVP composite films may have high potential as new wound‐dressing materials that provide and maintain the moist environment needed to prevent scab formation and dehydration of the wound bed. By a wound‐healing evaluation using a full‐thickness rat model experiment, it was found that a wound covered with a typical WBPU/PVP composite film (15 wt % PVP) was completely filled with new epithelium without any significant adverse reactions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis of polymeric electrospun nanofibers for application in waterproof‐breathable fabrics

This study focuses waterproof‐breathable fabric development by applying electrospun web of polyurethane (PU), PAN, and PES directly onto the substrate fabric. Advantages of textile fabrics of elastomeric nanofibrous membranes over gortex specimen are the mass production feasibility, high elastomeric properties, more body comfort parameters, and fabric production without holes and needle traces formation. In this work, we identified the PU nanofibrous membrane as the best and useful web for application in waterproof‐breathable fabrics. Air permeability, water vapor transport rate, and resistance to water penetration average value for the prepared PU fibers web (sample of S1) were about 10 ml/s, 430 g/m²/24 h, 15 cm H₂O. To improve waterproof‐breathable characteristics of the membrane, the effects of electrospinning parameters on the fibers morphology and waterproof‐breathable characteristics were investigated. PU concentration of 12% (w/w) and electrospinning voltage of 12 kV were identified as optimal conditions to reach uniform and fine PU nanofibers formation without any beads. Air permeability, water vapor transport rate, and resistance to water penetration average value for the final sample were recorded as about 2.5 ml/s, 840 g/m²/24 h, and 44 cm H₂O, correspondingly. POLYM. ENG. SCI. 56:143–149, 2016. © 2015 Society of Plastics Engineers     

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.     

Synthesis and properties of polyurethane‐urea‐based liquid bandage materials

To obtain ideal liquid bandage polymer materials, a series of polyurethane‐urea dispersions were synthesized from 4,4′‐diisocyanato dicyclohexylmethane (H₁₂MDI) and ethylene diamine with different molar ratio of polyol blend [polyethylene glycol (PEG, M_n = 2000 g/mol)/hydroxy terminated poly(dimethylsiloxane) (PDMS, M_n = ～ 550 g/mol)] and acetone/ethanol as a solvent. The effect of PDMS content in PEG/PDMS on the viscosity, mechanical properties, water contact angle/surface energy, insolubility in water (%), water absorption (%), equilibrium water content (%), and water vapor transmission rate (g m^?2 day^?1) of polyurethane‐urea films was investigated. As PDMS content increased, the water contact angle, insolubility in water, and tensile strength/elastic recovery of film sample increased; however, the surface energy, water absorption (%), equilibrium water content (%), and water vapor transmission rate (g m^?2 day^?1) of film sample decreased. By a wound‐healing evaluation using a full‐thickness rat model experiment, it was found that a wound covered with a typical polyurethane‐urea liquid bandage film (PD2 sample) was filled with new epithelium without any significant adverse reactions. These results suggest that the polyurethane‐urea‐based liquid bandages (samples: PD2 and PD3) prepared in this study may have high potential as new wound dressing materials, which provide and maintain the adequate wet environment required to prevent scab formation and dehydration of the wound bed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

聚醚/聚酯型亲水性聚氨酯防水透湿性能研究

以4,4’-二苯基甲烷二异氰酸酯(MDI)和1,4-丁二醇(BDO)为硬单体,制备了6组聚醚与聚酯或不同聚醚混合单体为软链段的嵌段型亲水性聚氨酯防水透湿涂层剂。研究了聚氨酯材料的微结构和软段结构对其防水、透湿性能的影响。结果表明,亲水性聚氨酯软链段的结构、组成、相对分子质量和含量及软、硬段相区间的微相分离程度对材料防水透湿性能的影响较大,亲水性聚氨酯的防水透湿性能主要取决于其中亲水性软链段的亲水性及其活动性。     

水性聚氨酯分散液的合成与研究

采用二级扩链技术 ,合成了同时具备阴离子型和非离子型大分子链结构的水性聚氨酯分散液 ;以红外光谱法作为半定量分析手段 ,进行了预聚过程动力学的研究 ,认为当初始合成温度为 70℃时 ,以丁酮为稀释剂 ,DMPA为离子型亲水单体 ,乙二醇为一级扩链剂 ,三乙胺为中和剂 ,三次乙基四胺为二级扩链剂 ,当n(NCO) /n (OH) =1 5时 ,预聚反应 5h ,扩链反应 2～ 4h ,可获得具有良好稳定性的水性聚氨酯分散液 ;超速离心沉降试验进一步证实了该结果。     

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.     

复合薄膜用水性聚氨酯胶粘剂的研究

以聚已二酸1,4-丁二醇酯(PBA)、甲苯二异氰酸酯(TDI)、二羟甲基丙酸(DMPA)等为主要原料合成了水性聚氨酯复膜胶,讨论了亲水性扩链剂DMPA用量对水性聚氨酯复膜胶的稳定性、耐水性、粘接强度等的影响;使用差示扫描量热仪(DSC)和原子力显微镜(AFM)观察了分子结构中的软、硬段微相结构分布。结果表明,当DMPA质量分数占预聚体总质量的2.67%～5.34%时能够制得稳定乳液;水性复膜胶乳液的粘度以及胶膜的吸水率随着亲水性扩链剂DMPA用量的增加而增加,而乳液的粒径随着亲水性扩链剂DMPA用量的增加而减小;硬段含量的增加会降低软段结晶,增加水性聚氨酯复膜胶高分子链的极性和粘接强度,当硬段质量分数为22.79%时,胶膜具有较好的T型剥离强度;提高复合压力能够显著提高T型剥离强度;该复膜胶对聚对苯二甲酸乙二醇酯(PET)膜有着比聚丙烯(OPP)膜更好的粘接效果。     

Effects of mixing procedure on the structure and physical properties of ester–ether-type soft segment waterborne polyurethane

The effects of the mixing procedure for the preparation of ester-ether-type waterborne polyurethane (WBPU) on the structure and properties of the cast film are studied here. The following three types of WBPU processing are examined: film formed from WBPU mixing ether-type WBPU with ester-type WBPU (CEM series), film formed from WBPU synthesized with PEG2000 and PCL2000 polydiol as the soft segments (CEB series), film formed from WBPU synthesized with triblock ester-ether copolydiol (PCL-polyethylene glycol-PCL) as the soft segment (CET series). The water vapor permeability (WVP) for the application to nylon fabrics is also studied. The results show that the mixing procedure greatly affects the properties of the ester-ether-type WBPU. The CEB series has better phase mixing than the CET series, and the CEM series has a phase boundary between the ester-and ether-type WBPU. The CEM series has a better Young's modulus and breaking stress and poorer breaking strain than the CEB and CET series. In addition, samples with lower ethylene oxide (EO) content have better phase mixing and mechanical properties. On the other hand, the ester-ether-type WBPU has a higher WVP than the ester-type WBPU and the WVP increases with the EO content. The order of the mixing procedures for WVP is CET > CEB > CEM. © 1996 John Wiley & Sons, Inc.     

防水透湿聚氨酯织物涂层剂研究进展

分别从微孔透湿型、无孔亲水导湿型、微孔透湿与亲水导湿结合型、智能透湿型及多功能防水透湿型等5大类型综述了各种防水透湿聚氨酯涂层剂的合成方法,评价了各类防水透湿聚氨酯涂层的优缺点,并展望了聚氨酯防水透湿涂层剂日后的主要研究方向。     

PCL–PEG–PCL triblock copolydiol-based waterborne polyurethane. I. Effects of the soft-segment composition on the structure and physical properties

This article examines the effects of the soft-segment composition on the structure and physical properties of waterborne polyurethane (WBPU) based on polycaprolactone–poly(ethylene glycol)–polycaprolactone (PCL–PEG–PCL) triblock copolydiol as the soft segment. The molecular weight of PEG in the soft-segment composition and soft-segment content (SSC) are varied in this study. The water-vapor permeability (WVP) for the WBPU-coated nylon fabric is also studied. The results showed that the glass transition temperatures (T_g's) of the soft segment decreased and its temperature range (ΔT_g's) narrowed with increase of SSC up to 63 wt % and decrease of the PEG molecular weight. The dynamic mechanical analysis results showed that the α-peak height of the soft segment increased with SSC when the SSC was less than 63 wt %. However, when SSC was more than 63 wt %, the α-peak height became smaller with increasing SSC due to the crystallization of the soft segment. At the same SSC, the number of spherulites was reduced and the spherulites become larger with decrease of the PEG molecular weight. As for the mechanical properties of the WBPU cast film, the breaking stress decreased and the breaking elongation increased with increasing SSC or decreasing PEG molecular weight. For the WBPU-coated nylon fabrics, either higher SSC or higher PEG molecular weight improves the WVP. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:883–892, 1997     

Surface and adhesion properties of poly(ethylene glycol) on polyester(polyethylene terephthalate) fabric surface: Effect of air‐atmospheric plasma treatment

The surface and adhesion properties of different molecular weight poly(ethylene glycol) (PEG) (400, 1500, and 3000 g/mol) on untreated and air‐atmospheric plasma‐treated PET woven fabrics were studied, with the aim of developing durable hydrophilic PET fibrous structures. PEG application was carried out by padding of the PET fabric in aqueous solution of PEG followed by curing and drying. The surface properties of the PEG‐coated PET fabrics were then characterized using wicking test to measure the water contact angle (θ°) and capillary weight (W_c), and using atomic force microscopy (AFM) images in the tapping mode. Results showed that without a prior air‐atmospheric plasma treatment of the PET fabric, the water contact angle decreased and capillary weight increased with the three PEGs, implying an increase in the hydrophilicity of both inner and outer PET fabric fiber surface. Air‐plasma treatment of the PET fabrics before PEG coating increases further the hydrophilicity of the inner fabric fiber surface: the capillary weight was almost doubled in the case of the three PEGs. Best results were obtained with PEG 1500: water contact angle decreasing from 82° to 51°, and the capillary weight increasing from 11 mg to 134 mg. Moreover, wash fastness test at room temperature and at 80°C confirms improved adhesion of PEG‐1500 to the plasma‐treated PET woven fabric surface, while under the same conditions the plasma‐treated PET without PEG loses completely its hydrophilic character. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

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.     

Enhanced Thermal and Mechanical Properties in Polyurethane/Au Nanocomposites

Summary: We have prepared waterborne polyurethane (WBPU) thin films containing gold nanoparticles by casting WBPU/Au solutions. The effect of the Au nanoparticle contents on the microstructure and properties of the composite films was investigated by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), field emission scanning electron microscopy (FESEM), transmittance electron microscopy (TEM), FTIR spectroscopy (FTIR) and dynamic mechanical analysis (DMA). The Au nanoparticles initially in the WBPU solution were well dispersed in the WBPU films cast and dried at 60 °C. The thermostability and mechanical properties of the polymer increased with Au contents up to 4.35 × 10^?2 wt.‐%, which was believed to be a result of induced crystallization in the presence of Au nanoparticles. The Au/WBPU nanocomposite containing with 6.5 × 10^?2 wt.‐% of Au resulted in the aggregation of Au particles, which leads to a worsening of the thermal and mechanical properties.

TEM micrograph of nanocomposites filled with 4.35 × 10^?2 wt.‐% of Au nanoparticles.