共查询到20条相似文献,搜索用时 15 毫秒
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Shuoshuo Wang Liqiang Yi Yini Fang Lina Wang Juming Yao Jaromir Marek Ming Zhang 《应用聚合物科学杂志》2021,138(21):50465
Recent years, phase change materials (PCMs) with potential to store and transform energy have attracted broad attention, especially in the field of thermal energy storage. However, the instability and leak proneness of PCMs limit their universal application. In this paper, core-shell fibers with 1-tetradecanol (TD) as core and poly(vinylidene fluoride) (PVDF) as shell were prepared via melt coaxial electrospinning method, and for improvement, the dye composed of crystal violet lactone (CVL) and bisphenol A (BPA) was added to the core to endow the fiber the function of reversible thermochromism. During the preparation process, it was found that the addition of NaCl could regulate the fiber morphology and strength its mechanical property. By adjusting the concentration of shell solution and the flow rate of core solution, the high-strength reversible thermochromic fibers were produced when polymer concentration was 24 wt% with a core feed rate of 0.4 ml/h. The latent heat of these fibers is up to 88.71 J/g. Besides, its color can change from blue to white when heated, and the transition temperature is around 38°C. And 100 thermal cycle tests of the fiber showed its strong thermal stability and thermochromic property. 相似文献
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Ana Patricia Martínez‐Camacho Mario Onofre Cortez‐Rocha María Mónica Castillo‐Ortega Armando Burgos‐Hernández Josafat Marina Ezquerra‐Brauer Maribel Plascencia‐Jatomea 《Polymer International》2011,60(12):1663-1669
Chitosan is a natural polymer with both antimicrobial activity and nanofiber‐forming capability. The electrospinning technique allows the production of chitosan nanofibers but still faces several problems such as the small number of suitable solvents for the process and the large number of factors affecting quality and production of the nanofibers, among others. The antimicrobial properties of chitosan nanofibers have been little studied; therefore, the most probable mechanism of action and the effect of the conformation or arrangement of the molecules in the nanofibers remain unknown. The presence of residual solvent in the materials is one factor that has complicated the assessment of the antimicrobial activity of chitosan nanofibers. The research in this area will be very important for the future of these materials. Copyright © 2011 Society of Chemical Industry 相似文献
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静电纺丝制备聚丙烯腈纳米纤维及其预氧化 总被引:1,自引:0,他引:1
利用聚丙烯腈/二甲基甲酰胺纺丝溶液由静电纺丝制备了聚丙烯腈纳米纤维,纳米纤维的直径在220~760nm。随着聚合物溶液浓度和纺丝施加电压的升高,纳米纤维的直径变大。采用热分析和热重分析研究了纳米纤维的热性能,还用红外光谱对纳米纤维预氧化过程分子化学结构的变化进行了表征,结果表明,纳米纤维有一个很尖锐的放热峰,是聚丙烯腈均聚物典型的放热峰。随着预氧化温度的升高,纤维的内部分子结构发生了变化,表现在红外光谱上最突出的是C≡N在2243~2241cm^-1峰的降低,以及C—H在1684cm^-1峰的降低。 相似文献
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Linda Härdelin Erik Perzon Bengt Hagström Pernilla Walkenström Paul Gatenholm 《应用聚合物科学杂志》2013,130(4):2303-2310
Dissolving pulp was depolymerized with 2.5M HCl into cellulose fractions with decreasing molecular weight relative to acid treatment time. The cellulose fractions were dissolved at various concentrations in the ionic liquid 1‐ethyl‐3‐methylimidazolium acetate (EmimAc) with co‐solvent DMSO at ratio 1 : 1 (w/w) and electrospun. Size exclusion chromatography was used to evaluate the molecular weight distributions and the rheological properties were characterized with a cone‐and‐plate rheometer. Scanning electron microscope was used to evaluate the fiber morphology, and thereby spinnability. Zero shear viscosity as a function of cellulose concentration show that all the solutions in this study are in the entangled semi‐dilute regime; where the polymer concentration is large enough for significant overlap necessary for chain entanglement. However, within the intervals studied, neither cellulose concentration nor molecular weight seems to be decisive for if a solution can be electrospun into fibers or not. It is rather the viscosity of the solution that is decisive for electrospinnability, even though the solution is in the entangled semi‐dilute regime. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 2303–2310, 2013 相似文献
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高效的析氧反应(OER)催化剂对于高效的能量储存和转换是必不可少的。本文采用静电纺丝法结合一步煅烧成功制备了镍铁合金/铁酸镍复合纳米纤维(NiFe/NiFe2O4),通过调变煅烧气氛、温度、元素比例等条件并结合X射线衍射(XRD)、扫描电镜(SEM)和电化学等测试手段对材料进行了相关表征与分析。其中电化学测试结果显示,该材料对碱性介质(1mol/L KOH)中析氧反应具有较高的电催化活性,最佳样品在电流密度达到10mA/cm2时所需过电位为380mV,并且在计时电位法测试10h后也表现出极佳的稳定性。 相似文献
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本研究采用去离子水为溶剂,以蛋清蛋白与聚氧化乙烯(PEO)混合进行静电纺丝制备纳米纤维,采用扫描电镜表征了蛋清蛋白/PEO纳米纤维的形貌特征,探究了溶液质量分数以及纺丝工艺参数对蛋清蛋白/PEO纤维形貌的影响,并采用元素分析测试表征了纤维的元素组成成分。实验结果表明,蛋清在质量分数20%~80%之间表现出可纺性,蛋清质量分数50%的纺丝溶液进行纺丝,在纺丝电压25kV、纺丝距离16cm、挤出速度0.2mL/h的条件下,可纺性最好,制备的纤维无珠串平均直径为389nm,且纳米纤维中11.02%为氮元素,说明蛋清中的蛋白质成功转化为了纳米纤维。蛋清蛋白具有生物友好、可降解、来源广泛等优点,本研究成功实现了蛋清蛋白纳米纤维绿色制造,为其在生物医药、电池催化等领域的应用提供了基础。 相似文献
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Stabilized electrospinning of heat stimuli/in situ crosslinkable nanofibers and their self‐same nanocomposites 下载免费PDF全文
We present a strategy for stabilizing the morphological integrity of electrospun polymeric nanofibers by heat stimuli in situ crosslinking. Amorphous polymer nanofibers, such as polystyrene (PS) and its co‐polymers tend to lose their fiber morphology during processing at temperatures above their glass transition temperature (Tg) typically bound to happen in nanocomposite/structural composite applications. As an answer to this problem, incorporation of the crosslinking agents, phthalic anhydride (PA) and tributylamine (TBA), into the electrospinning polymer solution functionalized by glycidylmethacrylate (GMA) copolymerization, namely P(St‐co‐GMA), is demonstrated. Despite the presence of the crosslinker molecules, the electrospinning polymer solution is stable and its viscosity remains unaffected below 60 °C. Crosslinking reaction stands‐by and can be thermally stimulated during post‐processing of the electrospun P(St‐co‐GMA)/PA‐TBA fiber mat at intermediate temperatures (below the Tg). This strategy enables the preservation of the nanofiber morphology during subsequent high temperature processing. The crosslinking event leads to an increase in Tg of the base polymer by 30 °C depending on degree of crosslinking. Crosslinked nanofibers are able to maintain their nanofibrous morphology above the Tg and upon exposure to organic solvents. In situ crosslinking in epoxy matrix is also reported as an example of high temperature demanding application/processing. Finally, a self‐same fibrous nanocomposite is demonstrated by dual electrospinning of P(St‐co‐GMA) and stabilized P(St‐co‐GMA)/PA‐TBA, forming an intermingled nanofibrous mat, followed by a heating cycle. The product is a composite of crosslinked P(St‐co‐GMA)/PA‐TBA fibers fused by P(St‐co‐GMA) matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44090. 相似文献
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以醋酸锌、硫脲为原料,采用简单的一步溶剂热法合成了花状Zn S微球,并分别在550、600和650℃下进行高温氧化处理,获得了Zn S/ZnO异质结构半导体材料。利用XRD、SEM、EDS、表面积分析仪、拉曼光谱仪和UV-Vis对材料的形貌、结构、比表面积和光学性质进行了测定,并以罗丹明B(Rh B)为模型污染物考察了样品的光催化性能。结果表明:原位合成的样品为立方相Zn S微球,经过550℃高温氧化1 h后,由于O原子的进入,生成少量ZnO,经过600℃高温氧化1 h后形成了Ⅱ型异质结构Zn S/ZnO,经过650℃高温氧化1 h后,样品基本上成为ZnO。随着高温氧化温度的升高,样品的禁带宽度整体呈下降趋势。光催化结果显示:Zn S/ZnO异质结构具备较优的光催化性能,紫外光照射40 min,Rh B降解率达到98.5%。 相似文献
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Fabrication and characterization of double‐network agarose/polyacrylamide nanofibers by electrospinning 下载免费PDF全文
This study focused on the preparation of electrospun cross‐linked double‐network (DN) of agarose/polyacrylamide (PAAm) nanofibers. The agarose formed the first‐network that was physical‐linked by the agar helix bundles. After UV‐irradiation, the chemically crosslinked PAAm was formed as the second network. The resulting cross‐linked DN agarose/PAAm nanofibers were characterized by scanning electron microscopy (SEM), contact angle, attenuated total reflectance‐Fourier transform infrared spectroscopy (ATR‐FT‐IR), thermogravimetric analysis (TGA), and tensile test. SEM analysis shows the agarose/PAAM nanofibers present with the thickness of 187 nm. Agarose/PAAm nanofibers were showing FT‐IR spectral peaks at ~1660, 1590, and 1070 cm?1 indicating the presence of both agarose and polyacrylamide in the crosslinked DN Agarose/PAAm nanofiber sheet, it suggests the strong interaction and good compatibility between the two components. Agarose/PAAm nanofiber sheet was showing thermal stability close to the pure polyacrylamide. From the tensile test study, agarose/PAAm strength improved by 66.66% compared to the pure agarose. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42914. 相似文献
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Photocatalytic properties of PMMA‐TiO2 class I and class II hybrid nanofibers obtained by electrospinning 下载免费PDF全文
Federico Ohlmaier‐Delgadillo Maria Monica Castillo‐Ortega Rafael Ramírez‐Bon Lorena Armenta‐Villegas Dora Evelia Rodríguez‐Félix Hisila Santacruz‐ Ortega Teresa del Castillo‐Castro Irela Santos‐Sauceda 《应用聚合物科学杂志》2016,133(48)
The preparation, characterization, and photocatalytic activity evaluation of three hybrid fibrous materials composed mainly by poly(methyl methacrylate) (PMMA), methyl methacrylate (MMA): 3‐(trimethoxysilyl) propyl methacrylate (TMSPM): titanium butoxide (TBT), TiO2 nanoparticles (NPTiO2), and TiO2 nanowires (NWTiO2) is studied. Two types of fibe?s structures were prepared, single and core‐shell structures. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis showed both structures, single and core‐shell, as well as the inorganic phase were dispersed in the hybrid fibers. Infrared spectroscopic analysis (FT‐IR) and thermal analysis showed the organic and inorganic components, as well as the weight percentage of the inorganic phase present in hybrid fibers. The photocatalytic activity of the hybrid fibers class I and II showed that the best photodegradative efficiency for methylene blue in aqueous solution (2.9 × 10?5 M) was 95%, provided by PMMA—10 wt % NPTiO2. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 44334. 相似文献
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《Ceramics International》2020,46(12):20088-20096
In this work, TiO2/MXene composites were successfully synthesized through an in-situ solvothermal method, where the morphology of TiO2 nanoparticles (NPs) was modified by different concentrations of agents. Ti3C2Tx with electronic storage characteristics was employed as a co-catalyst to enhance the photocatalytic degradation activity by capturing photogenerated electrons. The experimental results reveal that, with the help of C3H8O agents, TiO2 NPs are uniformly distributed on the surface of Ti3C2Tx. The TiO2/Ti3C2Tx-C3H8O composite showed the highest photocatalytic activity of 90.5% after 75 min under mercury light irradiation, which is 57.9% higher than that of the pure TiO2 photocatalyst. The photocatalytic activity is promoted due to the high photoelectron transmission performance of the TiO2/Ti3C2Tx composites. 相似文献
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Preparation and characterization of potassium sodium niobate nanofibers by electrospinning 下载免费PDF全文
Tony Lusiola Lovro Gorjan Frank Clemens 《International Journal of Applied Ceramic Technology》2018,15(5):1292-1300
In this work, we describe the electrospinning of (K,Na)NbO3 fibers and the effect of calcination temperature on the final phase composition. The envisaged application is for the fabrication of ferroelectric sensor hybrid materials. A solution of potassium acetate, sodium methoxide, and niobium ethoxide dissolved in methanol, acetylacetone, and acetic acid was mixed with polyvinylpyrrolidone (PVP) dissolved in methanol, producing a viscous solution for electrospinning. Confirmation that the proposed equation on the average diameter of fibers produced from high viscosity solutions was larger than that of a lower viscosity solution was made. A scanning electron microscopy (SEM) study showed the fibers to be cylindrical, smooth with diameters of around 400 nm and an aspect ratio >1000. The electrospun fibers were calcined from 700°C to 1050°C observing the fiber morphology. With increasing calcining temperature, the grain size increased. The calcined (K,Na)NbO3 nanofibers were brittle and generally found to display the “necklace effect.” 相似文献
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Poly(L ‐lactide acid)‐blend‐gelatin (PLLA‐gelatin) nanofibers were successfully fabricated by means of electrospinning. The different material components characterizing the properties of electrospun PLLA/G nanofibers were measured and the effect of PLLA weight ratios on such properties as morphologies, physical and chemical structure and mechanical profiles were analyzed. It was found that the fibers diameter increases and the ultimate tension‐stress enhances with increased PLLA weight ratio. The analysis of X‐ray diffractometry, differential scanning calorimetry, and Fourier‐transform infrared spectra demonstrated that the resultant nanofibers from electrospinning of PLLA‐gelatin solution are simple blends of these two components. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
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Suk‐Woo Park Hyun‐Su Bae Zhi‐Cai Xing Oh Hyeong Kwon Man‐Woo Huh Inn‐Kyu Kang 《应用聚合物科学杂志》2009,112(4):2320-2326
Nylon 6 nanofibers containing silver nanoparticles (nylon 6/silver) were successfully prepared by electrospinning. The structure and properties of the electrospun fibers were studied with the aid of scanning electron microscopy, transmission electron microscopy, energy‐dispersive spectroscopy, and X‐ray diffraction. The structural analysis indicated that the fibers electrospun at maximum conditions were straight and that silver nanoparticles were distributed in the fibers. Finally, the antibacterial activities of the nylon 6/silver nanofiber mats were investigated in a broth dilution test against Staphylococcus aureus (Gram‐positive) and Klebsiella pneumoniae (Gram‐negative) bacteria. It was revealed that nylon 6/silver possessed excellent antibacterial properties and an inhibitory effect on the growth of S. aureus and K. pneumoniae. On the contrary, nylon 6 fibers without silver nanoparticles did not show any such antibacterial activity. Therefore, electrospun nylon 6/silver nanocomposites could be used in water filters, wound dressings, or antiadhesion membranes. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
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E. Mendoza-Mendoza A.G. Nuñez-Briones L.A. García-Cerda R.D. Peralta-Rodríguez A.J. Montes-Luna 《Ceramics International》2018,44(6):6176-6180
By following a one-step, novel methodology, ZnO and Ag/ZnO heterostructures were successfully synthesized at room-temperature. This route is simple, effective, high yield (91%), environmentally friendly (green synthesis) and consists of a mechanically assisted metathesis reaction. The metathesis reaction used in this investigation showed two results: the in-situ generation of alkaline nitrates, LiNO3/NaNO3, and the direct crystallization of the desired Zn-based compounds in milling media; revealing a true mechanochemical synthesis of ZnO and Ag/ZnO (1.25, 2.50 and 4.50 mol% of Ag) heterostructures. Particles showed spherical-like morphologies and sizes smaller than 20 nm. The Ag/ZnO heterostructures exhibited higher photocatalytic activity than ZnO for degrading methylene blue (MB) dye. It was also shown that the presence of Ag (up to 1.25 mol%) nanoparticles (NPs) in ZnO accelerates the photodegradation reaction and then slows down with further increases in Ag contents. The 1.25-Ag/ZnO sample (10 mg) showed the highest photocatalytic activity (96%) for degrading MB (100 ml, 10 mg L?1) within 100 min under UV–Vis light irradiation (λ = 310 nm). 相似文献
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Yi Lin Yongyi Yao Xiaozhan Yang Na Wei Xuqing Li Ping Gong Ruixia Li Dacheng Wu 《应用聚合物科学杂志》2008,107(2):909-917
Poly(ether sulfone) (PES) nanofibers were prepared by the gas‐jet/electrospinning of its solutions in N,N‐dimethylformamide (DMF). The gas used in this gas‐jet/electrospinning process was nitrogen. The morphology of the PES nanofibers was investigated with scanning electron microscopy. The process parameters studied in this work included the concentration of the polymer solution, the applied voltage, the tip–collector distance (TCD), the inner diameter of the needle, and the gas flow rate. It was found from experimental results that the average diameter of the electrospun PES fibers depended strongly on these process parameters. A decrease in the polymer concentration in the spinning solutions resulted in the formation of nanofibers with a smaller diameter. The use of an 18 wt % polymer solution yielded PES nanofibers with an average diameter of about 80 nm. However, a morphology of mixed bead fibers was formed when the concentration of PES in DMF was below 20 wt % during gas‐jet/electrospinning. Uniform PES nanofibers with an average diameter of about 200 nm were prepared by this electrospinning with the following optimal process parameters: the concentration of PES in DMF was 25 wt %, the applied voltage was 28.8 kV, the gas flow was 10.0 L/min, the inner diameter of the needle was 0.24 mm, the TCD was 20 cm, and the flow rate was 6.0 mL/h. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008 相似文献