聚乳酸的静电纺丝行为及其纤维结构研究

用静电纺丝法制备了纤维平均直径为350～1900nm的聚乳酸纤维,用扫描电镜研究了纤维的形貌,并用实验设计方法研究了纺丝工艺参数(溶液浓度、电场电压)对纤维平均直径的影响,同时用差示扫描量热分析和X射线衍射研究了静电纺丝所得纤维的结构.研究结果表明:溶液浓度对纤维的平均直径有较大的影响,溶液浓度较低时易形成珠状结构的纤维,纤维的平均直径随着聚合物浓度的增大而增大,并随电场电压的增大而减小.与浇铸膜相比,静电纺丝所制得的纤维有较低的结晶度,并且结晶结构不够完善.由静电纺丝制备的聚乳酸纳米纤维膜在组织工程和药物缓释等领域有潜在的应用前景.     

静电纺工艺参数对含银PA6纳米纤维直径的影响

为了研究静电纺工艺参数对含银PA6纳米纤维直径分布的影响,采用静电纺丝技术,在不同含银量、纺丝液质量分数、纺丝电压、接收距离(C-SD)、喷嘴直径条件下制备出含银PA6纳米纤维膜.利用扫描电镜(SEM)及相关软件分析纳米纤维直径分布及形态,在银溶胶质量分数0.2%～0.4%、纺丝液质量分数10%～16%、纺丝电压12～21kV、接收距离9～18cm、喷嘴直径0.5～1.2mm的实验范围内,纳米纤维的平均直径为70～90nm;纳米纤维直径随银溶胶质量分数的增加而减小,随纺丝液质量分数的增加而增大,随喷嘴直径的增大而增大;电压和接收距离对纳米纤维直径的影响较小.     

CS/PA66复合纳米纤维的静电纺丝制备与药物缓释性研究

采用单一溶剂甲酸溶解壳聚糖(CS)和聚酰胺66(PA66),以静电纺丝的方式成功制得不同质量比的CS/PA66复合纳米纤维,通过红外光谱、扫描电镜等对复合纳米纤维的形貌、结构进行表征。结果证明:采用静电纺丝制得不同CS∶PA66质量配合比CS/PA66复合纳米纤维,纤维直径为40~100nm,纤维分布均匀,具有很好的连续性,增加黏度和电导率能够减小CS/PA66复合纳米纤维直径,提高复合纳米纤维堆叠密集度。CS∶PA66质量配合比为2∶8,CS/PA66复合纤维载药量为20%,释放50h,药物累计释放率最高达到88%,CS/PA66作为载药体系具有较好的药物缓释效果。     

n-HA/PVA复合纳米纤维的静电纺丝制备

采用静电纺丝法制备了羟基磷灰石/聚乙烯醇复合纳米纤维。并用X射线衍射、红外光谱、扫描电镜等分析测试手段对所制得纳米纤维的结构和形貌进行了表征。结果表明,静电纺丝的纤维中聚乙烯醇的结晶度明显降低,羟基磷灰石与聚乙烯醇为物理复合;复合纤维随着羟基磷灰石含量增加,直径增大且分布均匀性降低;羟基磷灰石/聚乙烯醇质量比为2/8时,复合纤维形貌较佳。说明静电纺丝法制备羟基磷灰石/聚乙烯醇复合纳米纤维是可行的。     

电纺制备明胶/壳聚糖/羟基磷灰石/氧化石墨烯抗菌复合纳米纤维的研究

本研究模拟细胞外基质成分与结构, 采用静电纺丝法成功制备出明胶/壳聚糖/羟基磷灰石/氧化石墨烯四元复合纤维。重点考察该体系中物质浓度对复合纤维形貌及抗菌性能的影响。结果表明: 明胶浓度增大会增大纤维的直径, 但浓度过大会出现粘连现象, 其最佳浓度为15~20%; 加入壳聚糖(CS)会出现细纤维分支, 其浓度为1%左右较佳; 增加羟基磷灰石(HA)浓度, 可提高电纺液的导电性, 降低纤维中的珠状物和粘联现象发生, 粒径为12 μm的HA浓度为5%时纤维形态较好; 加入氧化石墨烯后可使纤维形态均匀、光滑。最后对四元复合纤维进行了抗菌性能考察, 发现氧化石墨烯的加入增强了复合纤维的抗菌性。明胶/壳聚糖/羟基磷灰石/氧化石墨烯四元复合纤维对金黄色葡萄球菌和大肠杆菌均具有较好的抗菌效果。     

n-HA/PVA复合纳米纤维的静电纺丝制备EI北大核心CSCD

采用静电纺丝法制备了羟基磷灰石/聚乙烯醇复合纳米纤维。并用X射线衍射、红外光谱、扫描电镜等分析测试手段对所制得纳米纤维的结构和形貌进行了表征。结果表明,静电纺丝的纤维中聚乙烯醇的结晶度明显降低,羟基磷灰石与聚乙烯醇为物理复合;复合纤维随着羟基磷灰石含量增加,直径增大且分布均匀性降低;羟基磷灰石/聚乙烯醇质量比为2/8时,复合纤维形貌较佳。说明静电纺丝法制备羟基磷灰石/聚乙烯醇复合纳米纤维是可行的。     

静电纺PVDF/SiO_2原位复合隔膜的研究

采用原位复合溶胶-凝胶法配制复合纺丝液,通过高压静电纺丝制备出PVDF/SiO2复合纳米纤维膜。通过SEM表征了PVDF/SiO2复合纳米纤维的纺丝效果,同时对比了使用两种方法添加6%SiO2制得的PVDF静电纺复合纳米纤维的表面形貌及力学性能。研究了原位纳米SiO2的加入对膜的孔径变化以及力学性能的影响。结果表明,原位硅的加入,增加了纤维的表面粗糙度;降低了复合膜内的微孔直径,并使得微孔直径分布更加集中;改善了膜的力学性能,添加6%原位硅时效果最佳。在SiO2含量为6%时,与直接添加相比,原位复合法制得的复合膜力学性能更佳。     

仿树枝状PA6纳米纤维膜电纺工艺研究

在PA6纺丝液中添加有机盐四丁基氯化铵(TBAC),通过静电纺丝成功制得仿树枝状PA6纳米纤维膜,通过扫描电镜探讨聚合物用量,添加物用量以及纺丝工艺参数对纤维形貌的影响,分析表明当PA6用量为14%,TBAC用量为4%,电压为45kV,接收距离为15cm,注射速率为0.1mL/h时,纤维平均直径为116nm,制得的纳米纤维膜分支纤维较多,呈现形貌良好的树枝状结构。     

水溶液电纺制备葡萄籽多酚/明胶复合纤维

以水为溶剂,设计玻璃保温装置,采用静电纺丝技术制备了葡萄籽多酚/明胶复合纤维,系统探讨了浓度、温度、电压、流速等工艺条件以及葡萄籽多酚含量对葡萄籽多酚/明胶复合纤维形貌的影响.结果表明:当明胶浓度为24wt%时,随着温度和电压的增大,纤维平均直径先减小后增大,随葡萄籽多酚含量增大,纤维平均直径增大.通过加入适量葡萄籽多酚,可将纺丝速度从0.25 mL/h提高到0.90 mL/h,显著提高了工作效率;当葡萄籽多酚与明胶的质量比≥1:30时,纤维表面出现串珠;当葡萄籽多酚与明胶的质量比≥1:20时,可纺性变差.在明胶浓度为24wt%,葡萄籽多酚与明胶质量比为1:50,控制温度55 ℃,电压20 kV,接收距离12 cm,速率0.90 mL/h的条件下,制备了纤维直径分布集中,平均直径为515 nm的葡萄籽多酚/明胶复合纤维.明胶溶液中加入适量葡萄籽多酚不仅大大提高了纺丝效率,同时由于其良好的抗菌活性和对明胶的交联作用,使复合纤维膜可广泛应用于生物医药领域,特别是创伤敷料方面.     

熔体微分电纺PLA/ATBC空气滤膜的制备及性能

为了获得高效低阻、绿色环保的空气滤膜,采用熔体微分静电纺丝技术制备聚乳酸(PLA)/乙酰柠檬酸三丁酯(ATBC)(PLA/ATBC)空气滤膜,通过加入增塑剂ATBC改善熔体流动性,制得直径均匀的纳米纤维,并重点研究了空气过滤性能。研究结果表明:随着ATBC用量的增加,纤维膜结构由松散趋于紧实,纤维直径呈先减小后小幅度增加的趋势;ATBC用量为10%(wt,质量分数)条件下,纤维平均直径为0.42μm,制得的PLA/ATBC空气滤膜对粒径大于等于0.3μm的颗粒的稳态过滤效率最高达99.95%,过滤阻力为195.2Pa,具有较好的应用前景。     

Synthesis and characterization of nanofiber webs of chitosan/poly(vinyl alcohol) blends incorporated with silver nanoparticles

Nanofiber webs of chitosan (CS)/poly(vinyl alcohol) (PVA) blends incorporated with silver nanoparticles (AgNs) were fabricated by two different methods: a refluxing method and an annealing method. We found that the characterization and antibacterial activity of AgNs depended on not only the fabrication methods but also the weight ratio of CS and PVA in the CS/PVA blend. The change in the size and number of AgNs due to the interaction between AgNs and CS, in turn, affected the antibacterial property of the non-woven webs. Non-woven webs of CS/PVA nanofibers containing AgNs that were fabricated by the refluxing method showed higher antibacterial ability against Escherichia coli than did the other types of non-woven webs. The morphology of the electrospun non-woven webs was observed by field emission scanning electron microscopy. The characterization of AgN formation on the surface of electrospun fibers was examined by transmission electron microscopy, attenuated total reflectance-Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy.     

Effect of nano sized silver on electrospun nylon-6 fiber

We incorporated silver nanoparticles into a nylon solution, fabricated electrospun nanofibers, and studied various parameters of the electrospun fibers. We found that the addition of silver nanoparticles introduces antibacterial effects into nylon composite fibers. The average fiber diameter and fiber morphology was greatly affected when parameters such as solution concentration and the amount of silver nanoparticles were changed. The composite fibers that we prepared have the potential to be used as filtration membranes.     

Fabrication of electrospun polycaprolactone coated withchitosan-silver nanoparticles membranes for wound dressing applications

In this study, electrospun polycaprolactone membrane coated with chitosan-silver nanoparticles (CsAg), electrospun polycaprolactone/chitosan/Ag nanoparticles, was fabricated by immersing the plasma-treated electrospun polycaprolactone membrane in the CsAg gel. The plasma modification of electrospun polycaprolactone membrane prior to CsAg coating was tested by methylene blue stain and scanning electron microscope. The presence of silver and chitosan on the plasma-treated electrospun polycaprolactone membrane was confirmed by energy-dispersive X-ray spectroscopy and FT-IR spectrum. Scanning electron microscope observation was employed to observe the morphology of the membranes. The release of Ag ions from electrospun polycaprolactone/chitosan/Ag nanoparticles membrane was tested using atomic absorption spectrometry. Electrospun polycaprolactone/chitosan/Ag nanoparticles membrane inherited advantages from both CsAg gel and electrospun polycaprolactone membrane such as: increasing biocompatibility, mechanical strength, and antibacterial activity against both Gram-negative and Gram-positive bacteria. Thus, this investigation introduces a highly potential membrane that can increase the efficacy of the wound dressing process.     

Silver nanoparticles incorporated electrospun silk fibers

We present a simple and mass-producible method of incorporating silver nanoparticles on the surface of electrospun silk non-woven membranes for the fabrication of antimicrobial wound dressings. Nanofibrous silk membranes with fiber diameters of 460 +/- 40 nm were electrospun from an aqueous Bombyx mori fibroin solution. The electrospun membranes incorporating silver nanoparticles were prepared by dipping the membranes in aqueous silver nitrate (AgNO3) solution (0.5 or 1.0 wt%) followed by photoreduction. Field emission scanning and transmission electron microscopy showed that silver nanoparticles were generated on the electrospun silk fibroin nanofibers as well as inside them. The interaction between the silver nanoparticles and amide groups in the silk fibroin molecules was characterized using X-ray photoelectron spectroscopy.     

Aqueous synthesis of silver nanoparticle embedded cationic polymer nanofibers and their antibacterial activity

This paper describes the one-pot, aqueous synthesis of cationic polymer nanofibers with embedded silver nanoparticles. Poly[2-(tert-butylaminoethyl) methacrylate] (PTBAM) was used as a cationic polymer substrate to reinforce the antimicrobial activity of the embedded silver nanoparticles. Electron microscope analyses revealed that the as-synthesized nanofibers had diameters of approximately 40 nm and lengths up to about 10 μm. Additionally, silver nanoparticles of approximately 8 nm in diameter were finely embedded into the prepared nanofibers. The embedded silver nanoparticles had a lower tendency to agglomerate than colloidal silver nanoparticles of comparable size. In addition, the nanofibers with embedded silver nanoparticles exhibited excellent antibacterial performance against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Interestingly, the prepared nanofibers exhibited enhanced bactericidal performance compared with the silver-embedded poly(methyl methacrylate) (PMMA) nanofibers, presumably because of the antibacterial properties of the PTBAM substrate.     

基于PS/PAA两嵌段共聚物组装行为的银纳米粒子的制备

研究了两亲性嵌段共聚物聚苯乙烯-b-聚丙烯酸(PS-b-PAA)的胶束化行为,探讨了胶束对A gNO3的增溶作用以及胶束内A gNO3的还原反应。结果表明:PS-b-PAA在二甲苯中可以形成直径在40 nm~100 nm之间的胶束;PS-b-PAA胶束对A gNO3具有明显的增溶作用,但胶束溶液对A gNO3的溶解能力较弱,络合银的羧酸基团占总羧酸基团的7.4%。还原剂的用量及胶束内A gNO3的渗入量是影响胶束内银纳米粒子生成及形态的重要因素,随着还原剂加入量的增多,胶束中生成的银粒子尺寸减小,每个胶束中出现多个纳米粒子。     

Statistical optimization of the electrospinning process for chitosan/polylactide nanofabrication using response surface methodology

In this study, chitosan/polylactide (CP) blend solutions in trifluoroacetic acid as a co-solvent with different blend ratio were electrospun. Effects of different CP ratio and process parameters on the diameter of electrospun nanofibers were experimentally investigated. The fiber morphology and the distribution of fiber diameter were investigated by scanning electron microscopy. Response surface methodology (RSM) was used to define and evaluate a quantitative relationship between electrospinning parameters, average fiber diameters and its distribution for each chitosan–polylactide ratio. Applied voltage and polymer solution extrusion rate are the process variables which control the fiber diameter at similar spinning distances (15 cm). Fiber diameter was correlated to these variables by using a second-order polynomial function. The fibers were of diameter ranging from 94 to 389 nm. The predicted fiber diameters were in good agreement with the experimental results. Contour plots were obtained to identify the processing variables suitable for producing nanofibers. It was concluded that ratio of polylactide and chitosan in the blend polymer played an important role to the diameter of fibers and standard deviation of fiber diameter. The processing factors were found statistically significant in the production of nanofibers.     

Preparation of polyurethane cationomer nanofiber mats for use in antimicrobial nanofilter applications

In this study, polyurethane cationomers (PUCs) containing different amounts of quaternary ammonium groups were synthesized and successfully electrospun into non-woven nanofiber mats for use in antimicrobial nanofilter applications. The PUCs showed very strong antimicrobial activities against Staphylococcus aureus and Escherichia coli. The average diameters of the electrospun PUCs fibers decreased with increasing quaternary ammonium group content due to the increased charge density of the PUC solutions. The PUC nanofibers showed adhesion between nanofibers with various bonding sites, yielding mats with a film-like character and structural integrity.     

Preparation of ultra-fine polyimide fibers containing silver nanoparticles via in situ technique

Ultra-fine polyimide fibers containing silver nanoparticles were prepared by electrospinning from poly(amic acid)/(trifluoroacetylacetonoto)silver(I) (PAA/AgTFA) solution. Thermal curing of the silver(I)-containing fibers led to cycloimidization of the poly(amic acid) into polyimide with concomitant silver(I) reduction. The polyimide–silver fibers were characterized by FT-IR, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The average diameters of silver nanoparticles and ultra-fine PI fibers electrospun from solutions with different amounts of AgTFA were studied, and the crystal structure of silver nanoparticles was also presented.