Electrospinning fabrication and characterization of poly(vinyl alcohol)/montmorillonite/silver hybrid nanofibers for antibacterial applications

Poly(vinyl alcohol) (PVA)/montmorillonite clay (MMT)/silver (Ag) nanoparticles have been electrospun for fabricating PVA/MMT/Ag nanofiber in aqueous solutions. Since PVA is a water-soluble and biocompatible polymer, it is one of the best materials for preparation of antibacterial nanofiber. MMT has been used as an inorganic filler to enhance properties of homopolymeric nanofiber. The PVA/MMT/Ag nanofiber diameter increases with increasing contents of MMT clay and Ag nanoparticles. In preservation test, the PVA/MMT/Ag nanofiber confirms an excellent antibacterial performance, elucidating for practical uses as a new preservative. Moreover, the PVA/MMT/Ag nanofiber shows improved thermal properties.     

Preparation of α-Fe2O3 Nanofiber via Electrospinning Process

A thin PVA/FeCl3 composite fiber was prepared by using sol-gel processing and electrospinning tech niques. A nanofiber of α-Fe2O3 with the diameter of 50-150 nm was obtained via high temperature calcina tion of the PVA/FeCl3 composite fiber. The material was characterized by infra-red(IR) spectroscopy, X-ray diffraction(XRD), and scanning electron microscopy(SEM). The results show that the fiber after the calci nation at 700 ℃ was a pure α-Fe2O3 nanofiber.     

Coaxial Electrospinning Method for the Preparation of TiO2@CdS/PVA Composite Nanofiber Mat and Investigation on its Photodegradation Catalysis

TiO₂/PVA composite nanofiber mat was prepared via an electrospinning technology. SH‐TiO₂‐SiO₂ hybrid particles and PVA solution were injected through a coaxial syringe, yielding a composite nanofiber mat. The as‐prepared SH‐TiO₂‐SiO₂/PVA composite nanofiber mat was immersed in Cd²⁺ cation solution and S^2? anion solution in turn. Thus, yellow TiO₂@CdS/PVA composite nanofiber mats were prepared. By adjusting the number of times a mat was immersed in the Cd²⁺ and S^2? solutions, different amounts of CdS particles attaching to the mats were obtained. Both SH‐TiO₂‐SiO₂/PVA and TiO₂@CdS/PVA composite nanofiber mats were employed to catalyze the photodegradation of a model dye, methylene blue. The photodegradation performance could be greatly enhanced by the introduction of CdS particles anchoring onto TiO₂ particles. The photodegradation efficiency reached 99.2% within 180 min. Also, the nanofiber mat could be recycled and reused at least 10 times. The photodegradation efficiency of TiO₂@CdS/PVA composite nanofiber mats remained 68.8% for 10 cycles.     

Highly efficient catalytic performances of nitro compounds via hierarchical PdNPs-loaded MXene/polymer nanocomposites synthesized through electrospinning strategy for wastewater treatment

The problem of water pollution has become increasingly serious,and it has already threatened the survival of mankind and has become an obstacle to the healthy development of human health.Here,we prepared a novel polyvinyl alcohol(PVA)/polyacrylic acid(PAA)/MXene fiber membrane by electrospinning.After heat treatment of film and subsequent modification with Pd nanoparticles,PVA/PAA/MXene@PdNPs composite nanofiber membrane with high specific surface area and excellent catalytic performance was finally prepared.The uniform distribution of MXene sheets in the composite fiber membrane not only solves the problem that the MXene sheet is not easy to be monolayerized,but also can grow the self-reduced Pd nanoparticles on the MXene sheets.In addition,the composite nanofiber membrane exhibits excellent catalytic ability and cycle stability for 4-nitrophenol(4-NP) and 2-nitrophenol(2-NA),providing new strategy for the study of catalytic composite materials related to degradation of wastewater.     

魔芋葡甘聚糖/聚乙烯醇纳米纤维膜及其释药行为研究

为了研制药物缓释效果优良的薄膜材料,利用静电纺丝设备研制不同比重的魔芋葡甘露聚糖/聚乙烯醇纳米纤维膜,并通过扫描电镜、傅里叶变换红外光谱和示差扫描量热法表征纳米纤维膜的结构和性能,结合体外实验和数学模型研究其缓释行为.结果显示当魔芋葡甘露聚糖含量占纳米纤维膜总质量约76%时,纳米纤维膜中微纤丝粗细最均匀且结点较少,纳米纤维膜中魔芋葡甘聚糖和聚乙烯醇之间存在明显的相互作用,含有5-氨基水杨酸的纳米纤维膜在pH=7.4 PBS磷酸盐缓冲液中25 h的累积释放量大约为45%,显示出良好的药物缓释效果,其缓释行为与Higuchi模型具有较高的拟合度.研究表明利用静电纺丝设备研制的魔芋葡甘聚糖/聚乙烯醇纳米纤维膜可以为药物缓释载体的开发提供理论依据.     

Electrospinning and characterization of poly(vinyl alcohol)/chitosan oligosaccharide/clay nanocomposite nanofibers in aqueous solutions

Submicron fibers of the composite of poly(vinyl alcohol) (PVA), chitosan oligosaccharide [COS, (1→4)2-amino-2-deoxy-β-d-glucose], and montmorillonite clay (MMT) were prepared using electrospinning method with aqueous solutions. Scanning electron microscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD), thermal gravimetric analyzer, and tensile strength testing machine (Zwick) were utilized to characterize the PVA/COS/MMT nanofiber mats morphology and properties. The PVA/COS ratio and MMT concentration play important roles in nanofiber mat properties. XRD and TEM data demonstrated that exfoliated MMT layers were well-distributed within nanofiber. It was also found that the mechanical property and thermal stability were increased with COS and MMT contents.     

聚乙烯醇接枝微粒对黄酮类物质的吸附特性

以硅胶表面接枝有聚乙烯醇(PVA)的接枝微粒PVA/SiO₂为固体吸附剂, 对槲皮素和芦丁2种黄酮类化合物进行了吸附研究, 结果表明, 由于接枝微粒PVA/SiO₂表面含有高密度的羟基, 使得该接枝微粒与黄酮类化合物分子之间可形成多位点的常规氢键和π型氢键, 溶剂的竞争吸附对黄酮化合物的吸附容量产生很大的影响. 以弱极性的1,2-二氯乙烷(DCE)为溶剂时, 几乎不存在溶剂的竞争吸附, 槲皮素和芦丁具有最高的吸附容量, 分别为0.32 mmol/g(96 mg/g)和0.23 mmol/g(140 mg/g); 而在质子溶剂乙醇中, 强烈的溶剂竞争吸附使两者的吸附容量降至0.22 mmol/g(65 mg/g)和0.14 mmol/g(87 mg/g). 升高温度会减弱氢键作用, 甚至使氢键断裂, 导致吸附容量减小. 质子溶剂中电解质的存在, 对吸附作用产生负性影响. 功能微粒PVA/SiO₂对黄酮类化合物的吸附为放热过程, 且为焓驱动的吸附过程.     

疏水性聚丙烯酸/聚乙烯醇/葡萄糖淀粉酶复合纳米纤维膜的制备及酶学性质

利用混合静电纺丝将葡萄糖淀粉酶(GA)固定于聚丙烯酸(PAA)/聚乙烯醇(PVA)纳米纤维膜上,并通过鉴定固定化GA的酶学特征检验PAA/PVA可否成为一种优良的酶固定化载体。 对其理化性质和酶学特征进行鉴定,经红外光谱(FT-IR)和扫描电子显微镜(SEM)表征发现,GA可成功包埋于PAA/PVA纳米纤维膜内部;对包裹固定的GA进行酶学性质鉴定,发现固定化GA的最适反应温度为68 ℃,比游离GA提高了9 ℃;固定化GA的适用pH值范围明显变宽;热稳定性和存贮稳定性显著增强且可以重复使用。PAA/PVA纳米纤维膜是一种优良的酶固定化载体,可以通过混合静电纺丝包埋法简便地将蛋白质分子固定于其内部,具有一定的应用前景。     

Characterization,mechanical, and antibacterial properties of nanofibers derived from olive leaf,fumitory, and terebinth extracts

In this study, nanofiber structures were obtained with convenient polymers (PVA [polyvinyl alcohol] and PCL [poly ^o-caprolactone]) derived from the herbal extracts of olive leaves, fumitory, and terebinth plants. Optimum nanofiber structures were identified by measuring viscosity and conductivity values and performing morphological analysis, characterization, and mechanical tests of the prepared solutions. The potential use for wound healing at the most efficient level was determined as a result of antibacterial analysis of the structures obtained. APT (PVA/terebinth) and BFO (PCL/fumitory) nanofibers had the thinnest diameter range and the highest strength values. In terms of the determination of antibacterial effects, nanofiber structures of all 3 plant species proved to be effective against bacteria. The greatest effect was observed against Escherichia coli in the nanofiber structure containing olive leaves, with a zone diameter of 32 mm. In addition, APT and BFO nanofibers had the highest values of thinness and strength. In these 2 samples, using BFO against Staphylococcus aureus and APT against Candida albicans increased their areas of activity. In the literature review, no study was available about obtaining nanofibers, especially from fumitory and terebinth plants. This study aimed to increase knowledge on obtaining nanofiber structures, including various polymers derived from olive leaves, fumitory, and terebinth plants.     

Stabilization of electrospun poly(vinyl alcohol) nanofibrous mats in aqueous solutions

<正>The stability ofpoly(vinyl alcohol)(PVA) nanofibrous mats in water media was improved by post-electrospinning treatments.Bifunctional glutaraldehyde(GA) in methanol was used as a crosslinking agent to stabilize PVA nanofiber,but fiber twinning was observed frequently,and the highly porous structure of PVA nanofibrous mats was destroyed when the crosslinked fiber was soaked in water.To overcome this shortcoming,chitosan(CS) was introduced into the PVA spinning solution to prepare PVA/CS composite nanofibers.Their treatment in GA/methanol solution could retain the fiber morphology of PVA/CS nanofibers and porous structure of PVA/CS nanofibrous mats even if they were soaked in aqueous solutions for 1 month.Scanning electron microscopy(SEM),X-ray diffraction(XRD),thermal gravimetric analysis(TGA) and differential scanning calorimetry(DSC) were applied to characterize the physicochemical structure and thermal properties of PVA nanofibers.It was found that the water resistance of PVA nanofibrous mats was enhanced because of the improvement of the degree of crosslinking and crystallinity in the electrospun PVA fibers after soaking in GA/methanol solution.     

Fabrication of Poly（4-vinylpyridine） Nanofiber and Fluorescent Poly（4-vinylpyridine）/Porphyrin Nanofiber by Electrospinning

Poly（4-vinylpyridine）（P4-VP） nanofiber and fluoresent poly（4-vinylpyridine）/porphyrin（P4-VP/TPPA） nanofiber were respectively prepared by electrospinning. The effect of the concentration of P4-VP/dimethylformamide （DMF） electrospinning solutions on the morphology of P4-VP nanofiber was investigated and it was found that the average diameter of the nanofiber of P4-VP/DMF increased with the increase of the concentration of the spinning solution. After the addition of TPPA to the P4-VP/DMF spinning solution, the diameter of P4-VP/TPPA nanofiber became even due to the increase of the conductivity of the P4-VP/DMF-TPPA solution. The photoluminescent（PL） spectral analysis indicates that the emission peak position of P4-VP/TPPA nanofiber is almost the same as that of pure TPPA at about 650 nm without peak shift, and when it was stored for 20 days, the emission peak of P4-VP/TPPA nanofiber is also at 650 nm, indicating that the fluorescent property of P4-VP/TPPA nanofiber is stable. Fourier-transform iufrared（FTIR） spectrum confirms the chemical composition of the resulting P4-VP/TPPA composite nanofiber.     

PVA/GA/β-CD纳米纤维的制备及染料吸附性能

利用静电纺丝技术,以六氟异丙醇(HFIP)和水为溶剂,制备了环糊精(β-CD)含量为70%(质量分数)的聚乙烯醇(PVA)/β-CD纳米纤维,并经戊二醛(GA)交联处理得到了可用于染料吸附的PVA/GA/β-CD纳米纤维.通过红外光谱和扫描电子显微镜研究了交联反应前后纳米纤维组成和形貌的变化;考察了PVA/GA/β-CD纳米纤维对7种水溶性染料的吸附性能.结果表明,PVA/GA/β-CD纳米纤维对孔雀石绿、甲基紫和刚果红的吸附效果较好,最大吸附量分别为124.71,121.14和127.39 mg/g,4次吸附-解吸附循环后,染料去除率仍保持80%左右,在染料废水处理中具有良好的应用前景.     

聚羟基丁酸酯/碳纳米管复合纳米纤维膜的制备及其对重金属离子吸附分离性能的研究

以聚羟基丁酸酯和碳纳米管为原料,采用三氯甲烷/二甲基甲酰胺混合溶液为溶剂,利用静电纺丝技术制备了聚羟基丁酸酯/碳纳米管复合纳米纤维膜.研究了碳纳米管的含量对纳米纤维膜形貌和力学性能的影响,探讨了复合纳米纤维膜对重金属Cu(II)、Cd(II)和Pb(II)的吸附特性.实验结果表明:加入1 wt%碳纳米管能够将纳米纤维的平均直径从(728±146)nm降低至(468±89)nm,纳米纤维膜的比表面积从27.24 m~2/g提高至43.45 m~2/g;碳纳米管的复合能够有效增强聚羟基丁酸酯纳米纤维,当碳纳米管含量1 wt%为最佳,拉伸强度可达5.85 MPa,较纯聚羟基丁酸酯纳米纤维提升了115%.复合纳米纤维膜对重金属离子具有良好的吸附特性,其对Cu(II)、Cd(II)和Pb(II)的最佳吸附pH值为5,此时最大吸附容量分别为91.04、171.05和197.03mg/g,平衡吸附时间分别约为50、60和60 min,吸附率分别为1.79、2.83和3.28 mg/g/min;热力学和动力学分析表明,复合纳米纤维膜对重金属Cu(II)、Cd(II)和Pb(II)的吸附行为更符合Freundlich模型,吸附过程更符合Pseudo-second order模型;循环使用实验表明,重复使用5次后,其吸附容量可保持在初始值的87%以上,具有较好的使用寿命.     

抗污染PVA/PVDF电纺纳米纤维复合超滤膜的制备及过滤性能

以聚对苯二甲酸二醇酯(PET)无纺布为基底,聚偏氟乙烯(PVDF)纳米纤维为支撑层,聚乙烯醇(PVA)纳米纤维膜为分离层,采用静电纺丝法制备超滤膜,并用水/丙酮混合溶液对复合纳米纤维膜表面进行溶液处理,再加入戊二醛交联改性得到致密分离层.采用扫描电子显微镜(SEM)和红外光谱(FTIR)表征了复合超滤膜的表面,用水接触角(WCA)表征复合超滤膜的亲水性.在0.02 MPa恒压下死端过滤油/水乳液,测试复合超滤膜的过滤性能.结果表明,最优条件下制备的复合超滤膜死端过滤油/水乳液的通量为(42.50±4.78)L/(m~2·h),截留率达到(95.72±0.33)%;循环使用5次后,依然具有较好的过滤性能,常压下死端过滤复合超滤膜的纯水通量为(3469±28)L/(m~2·h).     

CdHgTe纳米晶/聚乙烯醇近红外纳米纤维的制备

采用一步法制备了性质稳定的CdHgTe纳米晶, 将其与聚乙烯醇水溶液共混, 通过静电纺丝方法获得了CdHgTe纳米晶/聚乙烯醇纳米纤维. 改变聚乙烯醇水溶液的浓度可以使纤维的直径在200~400 nm范围内可调. 所制备的纳米纤维在近红外区域具有很强的荧光, 而且发光峰位与原水相纳米晶的峰位基本一致, 这是采用其它方法制备纳米晶与聚合物的复合材料难以实现的. 通过与聚乙烯醇的复合, 纳米晶的热稳定性得到进一步增强, 在120 ℃下将纳米纤维加热2 h, 其形貌和发光性质都未发生明显的变化.     

PVA/DTC纳米纤维的制备及对铅离子的吸附行为

通过高压静电纺丝技术制备了聚乙烯醇/聚乙烯亚胺(PVA/PEI)纳米纤维膜, 对纤维膜进行功能化使其转化为对重金属离子具有高络合能力的聚乙烯醇/二硫代氨基甲酸盐功能化聚乙烯亚胺(PVA/DTC)纳米纤维膜. 研究了PVA/PEI纳米纤维膜的交联和功能化以及PVA/DTC纤维膜对铅离子的吸附行为. 结果表明, 高压静电纺丝法可制备出纤维直径分布均匀、 形貌良好的纳米纤维膜, 且交联、 功能化后仍能保持蓬松纳米纤维状的网状结构. PVA/DTC纳米纤维膜对铅离子吸附速率快, 吸附量容量高, 且具有良好的再生吸附能力, 是一种潜在的重金属离子高效吸附材料.     

Oxymatrine Loaded Cross-Linked PVA Nanofibrous Scaffold: Design and Characterization and Anticancer Properties

This study focuses on the fabrication, characterization and anticancer properties of biocompatible and biodegradable composite nanofibers consisting of poly(vinyl alcohol) (PVA), oxymatrine (OM), and citric acid (CA) using a facile and high-yield centrifugal spinning process known as Forcespinning. The effects of varying concentrations of OM and CA on fiber diameter and molecular cross-linking are investigated. The morphological and thermo-physical properties, as well as water absorption of the developed nanofiber-based mats are characterized using microscopical analysis, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. In vitro anticancer studies are conducted with HCT116 colorectal cancer cells. Results show a high yield of long fibers embedded with beads. Fiber average diameters range between 462 and 528 nm depending on OM concentration. The thermal analysis results show that the fibers are stable at room temperature. The anticancer study reveals that PVA nanofiber membrane with high concentrations of OM can suppress the proliferation of HCT116 colorectal cancer cells. The study provides a comprehensive investigation of OM embedded into nanosized PVA fibers and the prospective application of these membranes as a drug delivery system.     

不同结晶度聚乙烯醇水凝胶中水氢键缺损的拉曼光谱学研究

聚乙烯醇 (ＰＶＡ)是一种水溶性高分子 ,它在一定条件下可以部分结晶形成水凝胶 ,其结晶度必然影响其机械性能及水在水凝胶中的状态 .部分结晶交联所得的ＰＶＡ水凝胶 ,由于无毒、机械性能好常用来作为生物医用材料 ,如接触眼镜、人工关节润滑软骨等[1,2 ] .水凝胶是轻度交联的高分子网络 ,其内含有大量的水 ,高分子交联网络与水之间的相互作用决定着水凝胶的物理性质和化学性质[3 ,4 ] .一般认为 ,水凝胶中的水以三种状态存在 ,即键合水 (Ｂｏｕｎｄｗａｔｅｒ)、自由水 (Ｆｒｅｅｗａｔｅｒ)和间隙水 (Ｉｎｔｅｒｓｔｉｔｉａｌｗａｔｅｒ…     

恩诺沙星分子印迹纳米纤维膜的制备及性能

通过沉淀聚合法制备了恩诺沙星（ENRO）分子印迹聚合物（MIPs）微球,将其添加到聚乙烯醇（PVA）溶液中,采用静电纺丝技术制备了恩诺沙星分子印迹纳米纤维膜（MINFMs）. 利用扫描电子显微镜（SEM）研究了纺丝液浓度、纺丝电压及接收距离对MINFMs纤维直径及表面形貌的影响,从溶胀性、孔隙率、吸附容量及吸附选择性等几个方面对印迹膜的性能进行了评价. 结果表明,在环境温度25 ℃、相对湿度 40%~50%、MIPs加入量8%（质量分数）、PVA质量分数7%、纺丝电压15 kV和接收距离25 cm的条件下,得到的MINFMs的纤维形态良好,纤维平均直径为180 nm. MINFMs的溶胀度和孔隙率分别为136.76%和33.42%,均大于非印迹纳米纤维膜（NINFMs）. 动力学吸附性能结果显示,MINFMs在300 min后吸附基本达到平衡,且明显高于NINFMs的吸附量;Scatchard分析结果表明,在所研究的浓度范围内MINFMs对模板ENRO的结合位点是等价的,其离解平衡常数（K_d）与最大表观结合量（Q_max）分别为505.817 mg/L和3.862 mg/g. 与环丙沙星（CIP）和氧氟沙星（OFL）相比,MINFMs对ENRO表现出更强的特异性吸附能力.     

Assembly of well-aligned multiwalled carbon nanotubes in confined polyacrylonitrile environments: electrospun composite nanofiber sheets

Highly oriented, large area continuous composite nanofiber sheets made from surface-oxidized multiwalled carbon nanotubes (MWNTs) and polyacrylonitrile (PAN) were successfully developed using electrospinning. The preferred orientation of surface-oxidized MWNTs along the fiber axis was determined with transmission electron microscopy and electron diffraction. The surface morphology and height profile of the composite nanofibers were also investigated using an atomic force microscope in tapping mode. For the first time, it was observed that the orientation of the carbon nanotubes within the nanofibers was much higher than that of the PAN polymer crystal matrix as detected by two-dimensional wide-angle X-ray diffraction experiments. This suggests that not only surface tension and jet elongation but also the slow relaxation of the carbon nanotubes in the nanofibers are determining factors in the orientation of carbon nanotubes. The extensive fine absorption structure detected via UV/vis spectroscopy indicated that charge-transfer complexes formed between the surface-oxidized nanotubes and negatively charged (-CN[triple bond]N:) functional groups in PAN during electrospinning, leading to a strong interfacial bonding between the nanotubes and surrounding polymer chains. As a result of the highly anisotropic orientation and the formation of complexes, the composite nanofiber sheets possessed enhanced electrical conductivity, mechanical properties, thermal deformation temperature, thermal stability, and dimensional stability. The electrical conductivity of the PAN/MWNT composite nanofibers containing 20 wt % nanotubes was enhanced to approximately 1 S/cm. The tensile modulus values of the compressed composite nanofiber sheets were improved significantly to 10.9 and 14.5 GPa along the fiber winding direction at the MWNT loading of 10 and 20 wt %, respectively. The thermal deformation temperature increased with increased MWNT loading. The thermal expansion coefficient of the composite nanofiber sheets was also reduced by more than an order of magnitude to 13 x 10(-6)/ degrees C along the axis of aligned nanofibers containing 20 wt % MWNTs.