Properties of biodegradable PVA/sepiolite‐based nanocomposite fiber mats

In this study, poly(vinyl alcohol) (PVA) nanocomposite fiber mats with sepiolite were prepared via electrospinning technique. The measurements of fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), contact angle, scanning electron microscopy (SEM), and atomic force microscopy (AFM) were used for the characterization. The effect of polymer/sepiolite ratio and heat treatment on the properties of samples was investigated. The heat treatment which decreased the solubility of nanofibers and the addition of sepiolite resulted in a decrease in nanofiber diameter, contact angle with water, and water drop spreading rate on the material, and also resulted in an increase in water drop spreading rate inside the material. POLYM. COMPOS., 36:2334–2342, 2015. © 2014 Society of Plastics Engineers     

Poly(vinylidene fluoride) nanofiber-based piezoelectric nanogenerators using reduced graphene oxide/polyaniline

Recently, piezoelectric nanogenerators have received great interest as they can convert waste mechanical and radiative energy to electricity and can be used in self-energy generating systems and sensor technologies. In this study, electrospun poly(vinylidene fluoride) (PVDF) nanofiber-based piezoelectric nanogenerators with reduced graphene oxide (rGO), polyaniline (PANI), and PANI-functionalized rGO (rGOPANI) have been developed. Two different types of nanofiber mats were produced: First, rGO- and rGOPANI-doped PVDF nanofiber mats and second, rGO, PANI and rGOPANI-spray-coated PVDF nanofiber mats that have worked as nanogenerators' electrodes. Then, characterizations of samples were performed in terms of piezoelectricity, Fourier transform infrared (FTIR) spectrophotometric, X-ray diffractions (XRD), and scanning electron microscopy analyses. FTIR and XRD results confirmed that piezoelectric β-crystalline phase of PVDF occurred after the electrospinning process. Besides, maximum output voltages were obtained as 7.84 and 10.60 V for rGO-doped PVDF and rGOPANI-coated PVDF nanofiber mats, respectively. As a result, the doped nanofibers were found to be more successful due to the higher device accuracy in sensor technologies compared with spray-coated samples. However, spray-coating method proved to be more suitable technique for the production of nanogenerators on an industrial scale in terms of fast and large-scale applicability. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48517.     

电纺制备聚乳酸/聚醚砜复合纳米纤维膜及性能研究

采用同轴静电纺丝制备聚乳酸/聚醚砜(PLA/PES)复合纳米纤维膜,通过改变皮层溶液的挤出速率以及在芯层溶液中分别添加石墨烯（GO）、碳纳米管(MWCNTs)、埃洛石（HNTs）纳米粒子,制备了系列皮芯结构的复合纳米纤维膜。通过扫描电子显微镜、纤维强伸度仪、接触角测定仪等仪器测试表征了复合纳米纤维膜的纤维结构、拉伸强度、疏水性以及吸油倍率等性能。结果表明,制备的复合纳米纤维膜的接触角均大于130 °,表现出较好的亲油疏水性;当往芯液中添加石墨烯(GO)时,纳米纤维膜的吸油性能、拉伸性能最好,在甘油中的吸油倍率可达到67.61倍,食用油中可达到48.02倍,纵向断裂强度为62.68 MPa,横向断裂强度为43.98 MPa,横向断裂伸长率可达到697.76 %。     

Electrospinning of flux‐enhanced chitosan–poly(lactic acid) nanofiber mats as a versatile platform for oil–water separation

Environmentally friendly chitosan (CS)–poly(lactic acid) (PLA) nanofiber mats were designed and constructed by an electrospinning strategy. Studies on the wettability of the CS–PLA nanofiber mats showed that they possessed excellent hydrophobic and oleophilic properties in the pH range 1–12. A layered oil–water mixture was separated by CS–PLA nanofiber mats, and the oil flux of the mats collected by #10 stainless steel wire mesh (sample P‐10) was up to 511.36 L m^?2 h^?1, which was approximately 25 times higher than that of the mats collected by #0 stainless steel wire meshes (sample P‐N). The superior properties of the CS–PLA nanofiber mats may have been due to their tunable porous structure and fine flexibility. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45830.     

Electrospinning and crosslinking of zein nanofiber mats

Electrospinning processing can be applied to fabricate fibrous polymer mats composed of fibers whose diameters range from several microns down to 100 nm or less. In this article, we describe how electrospinning was used to produce zein nanofiber mats and combined with crosslinking to improve the mechanical properties of the as‐spun mats. Aqueous ethanol solutions of zein were electrospun, and nanoparticles, nanofiber mats, or ribbonlike nanofiber mats were obtained. The effects of the electrospinning solvent and zein concentration on the morphology of the as‐spun nanofiber mats were investigated by scanning electron microscopy. The results showed that the morphologies of the electrospun products exhibited a zein‐dependent concentration. Optimizing conditions for zein produced nanofibers with a diameter of about 500 nm with fewer beads or ribbonlike nanofibers with a diameter of approximately 1–6 μm. Zein nanofiber mats were crosslinked by hexamethylene diisocyanate (HDI). The tensile strength of the crosslinked electrospun zein nanofiber mats was increased significantly. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103:380–385, 2007     

Preparation and characterization of porous acrylate terpolymer nanocomposite for removal of diesel oil from artificial seawater

The present work deals with the preparation of magnetic acrylate terpolymer nanocomposite by emulsion polymerization. This nanocomposite was applied for the removal of diesel oil from artificial seawater by magnetic separation. Magnetic terpolymer nanocomposite was characterized by Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Specific surface area and pore size distribution were measured by the Brunauer–Emmett–Teller (BET) method. Contact angle (CA) measurement showed superhydrophobic properties of magnetic acrylate nanocomposite. Kinetics and isothermal studies indicate that oil sorption fits the second-order kinetic model and the Langmuir isotherm. Magnetic acrylate terpolymer can be regenerated for six cycles.     

Oil sorption behaviors of porous polydimethylsiloxane modified collagen fiber matrix

A facial and cost‐effective synthesis method of converting the leather protein solid wastes into a value‐added collagen matrix oil sorbent is successfully established for the first time. Hide powder fiber (HPF) was firstly prepared by using the pre‐tanned fleshing wastes from the leather industry, and then cross‐linked with epoxy‐terminated polydimethylsiloxane (PDMS) to produce hydrophobic collagen fiber, which was verified by the FT‐IR spectrum and contact angle analysis. Subsequently, a series of porous PDMS modified collagen‐based sorbents with roughness surface was successfully fabricated by solvent‐ and freeze‐drying methods respectively. The oil sorption capacity, sorption saturated time and retention capacity of the prepared sorbents was investigated. Combined with the SEM images, liquid displacement method and contact angle analysis, the results revealed that oil sorption capacities of the sorbent with lower pore size, higher porosity and rougher surface for silicone oil, motor oil and vegetable oil were approximate to 13.60, 12.50, and 11.92 g/g, respectively. Additionally, the sorption of oils is a quasi‐instantaneous process and also showed excellent oil retention capacity. It exhibited acceptable oil sorption performances as compared to commercial biomass sorbents. These findings indicated its potential as an eco‐friendly oil sorbent material. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42727.     

Envelopes with microplastics generated from recycled plastic bags for crude oil sorption

Oil spill accidents in marine environments and the lack of disposal of post-consumer plastic are environmental problems worldwide. This study presents a sustainable alternative for both issues through envelopes filled with microplastics (MPs) from recycled bags for the sorption of spilled crude oil. Through particle size analysis by three different sieves (4, 9, and 20 mesh), different MP sizes were characterized by scanning electron microscope (SEM), Brunauer–Emmett–Teller (BET), density, contact angle (CA), and Fourier-transform infrared spectroscopy (FTIR). According to their sizes, the MPs were distributed in envelopes and submitted to crude oil sorption capacity and efficiency evaluation. Three MP particle sizes were obtained (from the largest to the smallest, according to the sieve mesh, MP4, MP9, and MP20). SEM images of samples exhibited irregular and porous surfaces, and MP4 had the smallest pore size (8.6 μm). BET showed that MP4 had the highest surface area (0.074 m²/g). The CA > 90° exposed that all samples were hydrophobic. FTIR spectrum demonstrated that the samples from the recycled bags were made of high density polyethylene (HDPE). The MP4 envelopes also had the best crude oil sorption results in capacity and efficiency (1.73 g/g and 68%, respectively), being a promising recycled sorbent in crude oil spillage applications.     

Ultrasmall Ag nanocrystals supported on chitosan/PVA nanofiber mats with bifunctional properties

Bifunctional nanofiber mats consisting of chitosan (CS), poly(vinyl alcohol) (PVA), and silver nanocrystals (Ag NCs) have been fabricated by a facile electrospinning method. The formation and presence of Ag NCs supported on CS/PVA nanofibers are confirmed by ultraviolet‐visible spectroscopy and X‐ray diffraction. The morphology of the samples is characterized by transmission electron microscopy and scanning electron microscopy. The prepared Ag NCs/CS/PVA nanofiber mats show pronounced antibacterial activity against Escherichia coli and excellent filtration property for suspended particulate matter (SPM) particles. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46504.     

Superhydrophobic/superoleophilic micro/nanostructure nickel particles for oil/water mixture and emulsion separation

Nowadays, developing reusable and highly efficient materials for separating nano/micro-sized oil droplets from oil/water mixture and emulsion remains very challenging. Herein, hedgehog-like micro/nanostructure nickel particles were fabricated via a hydrothermal route. Thanks to its unique morphology, the octadecyltrichlorosilane (ODTS)-modified nickel particles show suitable superhydrophobicity/superoleophilicity properties with water contact angle, oil contact angle, and contact angle hysteresis values of 169.17° ± 2.13°, 0°, and 2.32°± 0.34°, respectively, making the potential sorbent for oil/water separation. The dense narrow thorns of superhydrophobic/superoleophilic nickel particles help the maximum scattering of particles on the surface and in the solutions. Hence, superhydrophobic/superoleophilic nickel particles demonstrated outstanding sorption capacity ranging from 3.86 to 5.27 (g/g) for a wide range of organic solvents and oils. Also, sorption capacities were retained even after 10 sorption cycles. Additionally, sorption capacities remain steady under acidic, alkaline, and high-saline conditions, indicating the high resistance in the harsh media. More importantly, ODTS-modified particles could also be used in oil/water emulsion separation with efficiencies of higher 99%. The appropriate resistance of hedgehog-like micro/nanostructure nickel particles to various environmental conditions as well as reusability and recyclability provides good opportunities for industrial applications of oil uptake from the oil/water mixture and emulsion.     

Open‐cell polypropylene/polyolefin elastomer blend foams fabricated for reusable oil‐sorption materials

The fabrication of high‐performance oil sorbents is of great significance for oil spill cleanup. The main objective of this study was to prepare open‐cell polypropylene/polyolefin elastomer (PP/POE) blend foams for fabrication of reusable sorbents for oil sorption. Open‐cell PP/POE blend foams were prepared via continuous‐extrusion foaming using supercritical carbon dioxide as the blowing agent. The interconnected open‐cell structure was characterized by scanning electron microscopy. The hydrophobicity and lipophilicity of PP/POE open‐cell foams were revealed by tests of contact‐angle measurement, water and cyclohexane sorption on the foam surface, CCl₄ and cyclohexane sorption in water, and oil/water separation. Further, the sorption tests indicated that PP/POE blend foams showed larger oil‐uptake capacities than pure PP foams. In addition, cyclic compression tests showed that PP/POE open‐cell foams had excellent ductility and significantly improved recoverability compared to pure PP foams. In cyclic sorption–desorption tests, the sorption kinetics was studied in terms of capacity and saturation time, showing that PP/POE foams kept larger sorption capacities for 10 cycles, with larger sorption rates and good reusability. Based on the high open‐cell content, the good hydrophobic and oleophilic properties, the high oil‐sorption capacity, the improved recoverability, the large sorption rate, and the good reusability in cyclic oil‐sorption performance, the PP/POE open‐cell foams have shown promise as potential oil sorbents in applications for oil spill cleanup. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43812.     

Hydrophobic surface modification of FMSS and its application as effective sorbents for oil spill clean‐ups and recovery

Superhydrophobic sponge‐like materials are attracting more attention in recent years as potential sorbent materials for oil spill clean‐up. In this work, the authors report the incorporation of hydrophobic structural features into a superhydrophilic pristine formaldehyde‐melamine‐sodium bisulfite copolymer sponge (FMSS) by N‐acylation with a fatty acid derivative, for use as an oil sorbent in oil spill clean‐ups. This resulted in our ability to transform the surface properties of the sponge skeleton to superhydrophobic with a contact angle of 143°. The acylated FMSS (a‐FMSS) was shown to retain the interconnected porous structure, and was characterized with microscopic and spectroscopic analyses. Sorption experiments with engine oil and chloroform showed that a‐FMSS had a very high oil sorption capacity (amounting to 99 and 168.2 times its own weight respectively) than commercial nonwoven polypropylene sorbent. In this view, a‐FMSS is considered to be a promising oil sorbent for potential applications in large‐scale oil spill clean‐ups. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4090–4102, 2017     

Morphology,polymorphism, and metal ion adsorption studies of electrospun nanofibers based on PVDF and organically modified layered double hydroxide

Nonwoven nanofiber mats of polyvinylidene fluoride (PVDF) with modified layered double hydroxide (MLDH) were prepared by electrospinning. The fiber morphology was studied using scanning electron microscopy. X‐ray diffraction and FTIR spectroscopy was used to characterize the polymorphism in electrospun mats. Fibers of diameter in the range 80–800 nm with beads of about 2–3 µm size were observed for pure PVDF, while in case of PVDF/MLDH nanocomposites the number and size of beads were found to be significantly reduced. Uniform and fine nanofibers were obtained at lower content of MLDH, but slightly rough surface was seen for higher content. FTIR and X‐ray diffraction patterns signify various crystalline forms of electrospun PVDF. The content of polar β‐crystalline phase of PVDF, which exhibit piezo and ferroelectric properties was found to be enhanced significantly due to reinforcement of MLDH. Use of these nanofiber mats for heavy metal Cu (II) removal was explored. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4508–4515, 2013     

Spilled‐Oil Sorbents Prepared by Recycling of Eutrophicated Aquatic Plants

Recycling of four eutrophicated aquatic plants including Eichhornia crassipes, Herba Lysimachiae, Alternanthera philoxeroides, and Potamogeton crispus as spilled‐oil sorbents was investigated. The rough and hydrophobic structures of aquatic plants were observed by scanning electron microscopy and contact angle measurements. The four plants exhibited superior oil sorption capacities, especially the stalk of Eichhornia crassipes. Such high oil sorption was ascribed to their high capillarity and hydrophobic surface. The aquatic plants absorbed oil to reach adsorption saturation within one minute. The oil sorption capacity was significantly affected by particle size, but was hardly influenced by temperature. The results demonstrated that the aquatic plants could be applied as low‐cost and environment‐friendly spilled‐oil sorbents.     

Gel based on modified chitosan for oil spill cleanup

A method has been developed for obtaining a polymer porous gel and coating based on nontoxic and environmentally friendly components: chitosan, citral, and glutaraldehyde. The chemical structure and morphology of the polymer gel were investigated by infrared spectroscopy and scanning electron microscopy, respectively. The contact angles were determined using a goniometer, and the water and oil absorption of the gel were determined by the gravimetric method based on changes in the gel mass. Measurement of the contact angle θ of transmission oil and water drops on the coating surface showed the hydrophobic nature of the coating (θ = 90° for water and θ = 0° for oil). Study of the sorption properties of the resulting gel showed high sorption capacity with respect to transmission oil (9.05 kg/kg) and low sorption capacity with respect to water (2.46 kg/kg). It was found that after oil desorption from the loaded aerogel, it can be reused. The potential possibility of recycling the spent gel through its biodegradation in the soil was shown. Because of the excellent sorption capacity, high porosity, low density, and soil degradability, the developed gel has a great potential for application in the field of environmental purification from oil pollution.     

Preparation of cellulose triacetate aerogel via non-solvent impacted thermally induced phase separation for oil absorption

The oil spill has caused significant attention on a global scale due to its damage to the environment and the economy. The development of economically and ecologically friendly oil sorbent materials has important meaning for the oil spill concern. In this work, we explored the non-solvent impacted thermally induced phase separation (NITIPS) method to prepare the cellulose triacetate aerogel (CA) with low density (6.4–40.5 mg/cm³), high porosity (96.9–99.5%), large water contact angle (>129°) and high specific surface area (193–573 m²/g) as the oil sorbent material. The oil absorption capacity of CA with vegetable oil and vacuum pump oil reached 80.8 g/g and 38.9 g/g, respectively, consistent with Fick's law of diffusion. Moreover, the NITIPS method provided simpler process and controlled the shape of CA compared with the traditional thermally induced phase separation method. This study proved that the CA prepared by NITIPS methods played an important role as a potential oil absorption solids in the field of oil spill and organic chemical leakage.     

氟化SiO2纳米颗粒双疏涂层的制备及性能研究

采用氟化硅烷偶联剂对合成的单分散SiO2纳米颗粒进行表面接枝改性,并通过旋涂法将制备的氟化SiO2颗粒沉积在硅晶基板上.采用粒径分析仪、傅里叶变换红外光谱仪(FTIR)、热重分析仪(TG-DTA)、扫描电镜(SEM)和接触角测量仪对氟化SiO2纳米颗粒涂层的表面形貌、化学组成、接枝密度和润湿性能进行分析表征.结果表明:氟化硅烷偶联剂在SiO2纳米颗粒表面的接枝密度为5.94 nm-2;制备的氟化SiO2纳米颗粒薄膜具备微纳米双重复合网络结构,增加了涂层表面的粗糙程度;氟化SiO2纳米颗粒涂层展现出超疏水和强疏油性能,水和柴油在氟化SiO2纳米颗粒薄膜上的接触角分别为158.4°和125.7°.     

Acrylonitrile/vinyl acetate copolymer nanofibers with different vinylacetate content

In this study, free radical copolymerization of acrylonitrile (AN)–vinyl acetate (VAc) was performed for five different feed ratio of VAc (wt %) by using ammonium persulfate (APS) in the aqueous medium. The effect of VAc content on the spectrophotometric and thermal properties of AN–VAc copolymers was investigated by Fourier Transform Infrared–Attenuated Total Reflectance spectrophotometer (FTIR–ATR), differential scanning calorimeter (DSC), and thermal gravimetric analyzer (TGA). Thermal stability of homopolymer of AN is improved after being copolymerized. The electrospun P(AN‐co‐VAc) nanofibers were fabricated and the effect of VAc content on the morphologic properties of nanofibers was studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The viscosity of the solution had a significant effect on P(AN‐co‐VAc) electrospinning and the nanofiber morphology. The average diameters of P(AN‐co‐VAc) nanofibers decreased 3.4 times with increasing feed ratio of VAc wt %. The P(AN‐co‐VAc) electrospun nanofiber mats, with the feed ratio of 30 wt % VAc, can be used as a nanofiber membrane in filtration and as a carbon nanofiber precursor for energy storage applications due to high surface to volume ratio, high thermal stability, homogeneous, and thinner nanofiber distribution. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Superhydrophobic PCL/PS composite nanofibrous membranes prepared through solution blow spinning with an airbrush for oil adsorption

Superhydrophobic composite nanofibrous membranes(PP) were prepared from polycaprolactone (PCL)/polystyrene (PS) through solution blow spinning with an airbrush for oil adsorption. PP membranes were characterized by fourier transform infrared spectroscopy, scanning electron microscopy, water contact angle, X‐ray Photoelectron Spectroscopy, X‐ray diffractometer, and thermogravimetric analysis instrument. The effects of mass ratio of PCL and PS on the morphology, porosity, density, cyrstallinity, thermal stability, and oil adsorption ability were investigated. PP membranes had higher density than PCL and PS, while better hydrophobicity. The saturation adsorption capacity of PP to peanut oil, motor oil, and diesel oil is 16.89 g/g, 20.33 g/g, and 12.17 g/g, respectively. After 6 cycles of reutilization, the adsorption capacity to peanut oil, motor oil, and diesel oil remained at 6.16, 7.46, and 5.33 g/g, respectively, higher than that of pure PCL membrane.The water/oil adsorption selectivity of PP was about 7:100. PP had higher oil adsorption capacities and better water/oil adsorption selectivity than the commercial oil absorbent polypropylene. PP membrane could be prepared and used in situ to separate oil from oil/water mixture. POLYM. ENG. SCI., 59:E171–E181, 2019. © 2018 Society of Plastics Engineers     

Synthesis and performance of different polyurethane foams as oil sorbents

Oil sorption (g g^?1) through different polyurethane foams has been investigated in this study. Polyurethane foams were synthesized with different additives: glycerol, propylene glycol, polyethylene glycol 400, and 1‐dodecanol. All foams were applied as sorbents of diesel, motor oil, gasoline, kerosene, and crude oil. The foams were characterized using Fourier transform infrared spectroscopy, thermogravimetry and differential scanning calorimetry, compressive resistance at 10% deformation and the elastic modulus, scanning electron microscopy, and apparent density. The best performance of oil sorption was achieved with PUF‐3, which has the greatest amount of the chain extender polyethylene glycol 400 and lowest density of all the evaluated foams. The sorption capacities (g g^?1) of PUF‐3 were 16.8 (diesel), 15.7 (gasoline), 20.7 (oil motor), 25.4 (kerosene), and 29.8 (crude oil) and 100% removal of diesel from water was achieved, approximately. The foams with chain extenders and lower density values performed better as oil sorbents. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45409.