Preparation of CuS nanoparticles embedded in poly(vinyl alcohol) nanofibre via electrospinning

Poly(vinyl alcohol) (PVA)/CuS composite nanofibres were successfully prepared by electrospinning technique and gas-solid reaction. Scanning electron microscopic (SEM) images showed that the average diameter of PVA/CuS fibres was about 150–200 nm. Transmission electron microscopy (TEM) proved that a majority of CuS nanoparticles with an average diameter of about 15–25 nm are incorporated in the PVA fibres. X-ray diffraction (XRD) analyses and electron diffraction pattern also revealed the forming of CuS crystal structure in the PVA fibres.     

静电纺丝制备超细纤维复合材料

主要探讨了固化距离、纺丝电压对聚乙烯醇和淀粉、聚乙烯醇和壳聚糖共混液静电纺丝的影响,并尝试了多喷头静电纺丝制备超细长纤维复合材料。运用扫描电镜、红外光谱和差示扫描量热仪等对制得的超细复合材料的纤维形态、结构和力学性能进行研究,制得了纤维形貌与力学性能优异的、结构均匀的超细长纤维复合毡;多喷头电纺时,溶剂挥发影响着复合毡形态与性能。经过乙醇浸泡处理后,纯聚乙烯醇纳米纤维毡的结晶度和力学性能明显提高。     

无皂反相悬浮交联法制备聚乙烯醇球珠的研究

利用聚乙烯醇(PVA)自身所具有的"双亲性"特征,在不引入悬浮分散剂的条件下,通过无皂反相悬浮交联法制备出交联的PVA球珠,且产物流动性、分散性、几何形态均良好.实验选取液体石蜡为连续相,戊二醛(GA)为交联剂,盐酸(HCl)为催化剂.通过偏光显微镜,扫描电子显微镜(SEM)的观察,发现PVA球珠表面光滑无粘连.同时还讨论了体系pH值、GA用量等因素对PVA成球时间及球珠溶胀性能的影响.     

硫酸酯化聚阴离子PVA的合成及表征

硫酸与聚乙烯醇(PVA)经酯化制备PVA聚阴离子电解质.分别考察了反应时间、反应温度等对取代度的影响.采用红外光谱(IR)、扫描电镜(SEM)对硫酸酯化PVA聚阴离子电解质的结构进行了表征,测定了其热稳定性和导电性.     

聚乙烯醇/纤维素纳米纤热塑性复合材料的制备及表征

将聚乙烯醇(PVA)、纤维素纳米纤(CNFs)通过熔融共混成功制备出高性能PVA/CNFs热塑性复合材料。采用扫描电镜、红外光谱、X射线衍射、差示扫描量热分析、热重分析对PVA/CNFs复合材料的微观形态及结构进行表征,对复合材料的物理力学性能进行测试。结果表明,选用适当的增塑剂与PVA、CNFs组合可实现PVA/CNFs共混体系的热塑成型;CNFs与PVA间的氢键作用有助于提高CNFs与PVA基体之间的相容性,从而优化PVA/CNFs复合材料的力学性能,拉伸强度从19.5 MPa增加到34.3 MPa,弹性模量从114.4 MPa增加到287.5 MPa。     

PES基复合超细多孔纤维及其形貌初探

选取二甲亚砜(DMSO)作聚醚砜(PES)与聚乙烯醇(PVA)混合体系的溶剂,采用静电纺丝法制备了PES/PVA复合超细纤维,再用水抽提去除纤维中的PVA组分,成功地获得了PES基多孔超细纤维。运用扫描电镜(SEM)、透射电镜(TEM)、原子力显微镜(AFM)等表征手法观测研究了不同PVA含量时纤维及孔洞的形貌。     

Thermomechanical properties of poly(vinyl alcohol) plasticized with varying ratios of sorbitol

The objective of this work is to study the thermal and mechanical properties of films based on blends of poly(vinyl alcohol) (PVA) with different weight percent of sorbitol. Solid-state PVA/sorbitol polymer membranes were prepared by a solution casting method. The characteristic properties of these polymer membranes were examined by thermo-gravimetric analysis (TGA), differential scanning calorimetry (DSC), nanoindentation methods and by Fourier Transform Infrared (FTIR) spectroscopy. It was found that the thermal properties (glass transition, T_g, melting point, T_m and decomposition temperature, T_d) for PVA blends showed a decrease proportional to the sorbitol concentrations. The hardness and elastic modulus obtained from nanoindentation test were also found to decrease with increase in plasticizer concentration. FTIR confirmed the reduction in hydrogen bonding between PVA chains in favour of formation new bonding between the plasticizer and the PVA chains.     

Preparation and characterization of electrospun core sheath nanofibers from multi-walled carbon nanotubes and poly(vinyl pyrrolidone)

Electrospinning is a versatile technique to prepare polymer fibers in nano to micrometer size ranges using very high electrostatic fields. Electrospun nanofibers with tunable porosity and high specific surface area have various applications, including chromatographic supports for protein separation, biomedical devices, tissue engineering and drug delivery matrices, and as key components in solar cells and supercapacitors. Unspinnable materials such as nanoparticles, nanorods, nanotubes or rigid conducting polymers can also be electrospun into fibers through co-axial electrospinning. In this study, we have prepared core-sheath nanofibers utilizing co-axial electrospinning. The core portion of these electrospun fibers consists of multi-walled carbon nanotubes and the sheath portion is poly(vinyl pyrrolidone) (PVP). Various morphologies were obtained by changing both core and sheath solution concentrations. The core-sheath nanofibers were characterized by scanning electron microscopy and transmission electron microscopy, to confirm core-sheath morphology, thermogravimetric analysis, and mechanical strength testing. The electrical conductivity of the surfaces of poly(vinyl pyrrolidone) fibers and poly(vinyl pyrrolidone)-multi-walled nanotube fibers were both 10(-15) S/m. The highest bulk conductivity observed for the poly(vinyl pyrrolidone)-multi-walled nanotube fibers was 1.2 x 10(-3) S/m.     

聚乙烯醇缩苯甲醛的合成与热稳定性研究

以聚乙烯醇（PVA）和苯甲醛为原料,二甲基亚砜为溶剂,对甲基苯磺酸为催化剂,采用均相工艺合成得到聚乙烯醇缩苯甲醛（PVB）。通过衰减全反射-傅里叶红外光谱（ATR-FT-IR）、紫外-可见光谱（UV-Vis）、核磁共振氢谱（1 H NMR）、核磁共振碳谱（13C NMR）等测试手段对聚乙烯醇缩苯甲醛结构进行了表征。利用差式扫描量热仪（DSC）测定了聚乙烯醇缩苯甲醛的玻璃化温度（Tg）。采用差热分析（DTA）和热重分析（TGA）对聚乙烯醇缩苯甲醛热稳定性进行了研究。DSC结果表明聚乙烯醇缩苯甲醛的玻璃化温度为106.0℃。DTA和TGA结果表明聚乙烯醇缩苯甲醛热稳定性良好,在空气中150℃仍未见分解。     

壳聚糖/聚氧乙烯复合纺丝液性能对静电纺丝的影响

为了研究壳聚糖/聚氧乙烯复合纺丝液性能对静电纺丝的影响,利用质量分数为3％的壳聚糖(CS)与聚氧乙烯(PEO)以不同的质量比溶解在浓度为50％的冰乙酸水溶液中制备了CS/PEO复合纺丝液,采用静电纺丝技术制备了CS/PEO复合纳米纤维.用扫描电子显微镜(SEM)对制备出的CS/PEO复合纳米纤维进行表征,并测试了CS/PEO复合纺丝液的溶液性能.从复合纺丝液性能对静电纺纤维成型的影响机理角度对实验结果进行了分析.分析结果表明,在其他静电纺丝参数一定时,纺丝液黏度影响射流的稳定性,从而影响纤维的形貌和直径.只要纺丝液电导率在合适的范围内,对静电纺的影响不大.从泰勒的临界公式中得出了纺丝液临界电压与纺丝液表面张力最佳值的一一对应关系,并与本实验中的实验数据相吻合.     

Preparation of poly (vinyl alcohol)/silica composite nanofibers membrane functionalized with mercapto groups by electrospinning

Membranes of poly vinyl alcohol (PVA)/silica functionalized with mercapto groups are synthesized by electrospinning. Scanning electron microscopy (SEM) studies showed that the fiber diameters are in the range of 200-300 nm. The thickness of nanofiber decreases with an increase in calcination temperature. The results of Fourier transform infrared (FTIR) indicated that PVA/silica nanofibers are functionalized by mercapto groups via the hydrolysis poly-condensation method. N₂ adsorption-desorption showed that organic molecules can be removed completely when the PVA/silica composite fibers are calcinated at 800 °C. The fibers calcinated at 800 °C were pure inorganic silica species with a mesoporous structure. These mercapto groups functionalized PVA/silica nanofibers have a great potential application in the field of adsorption of heavy metal ions.     

含共轭结构的ZnO/聚乙烯醇复合光催化材料的制备与性能

以ZnO和NaOH为原料,采用低温水热法合成纳米ZnO 半导体材料,并与聚乙烯醇（PVA）水溶液在超声作用下混合,通过直接煅烧制备出PVA中含共轭双键碳链结构（C）的ZnO/PVA_C复合光催化材料。采用 SEM、XRD、FTIR、Raman和UV-Vis DRS对样品进行表征。结果表明:ZnO/PVA_C复合光催化材料由结晶性能良好的纳米ZnO和具有共轭结构的聚合物组成,且界面间通过化学键Zn-O-C相连接;在模拟太阳光照射下,ZnO/PVA_C复合光催化材料对光的吸收响应可扩展到整个可见光区,并产生较高光电流。光催化性能测试结果表明,ZnO/PVA_C复合光催化材料对罗丹明B的降解催化性能（30 min降解率接近于100%）明显高于纯纳米ZnO。      

聚乙烯醇接枝聚异丁烯马来酸酐的合成及自组装

主要研究了以聚乙烯醇(PVA)为主链,聚异丁烯马来酸酐(PIBSA)为支链的两亲性接枝共聚物的制备及在溶液中的自组装行为.接枝共聚物由PIBSA和PVA1799通过酯化反应得到,改变投料比能得到不同接枝率的共聚物.以二甲基亚砜(DMSO)做共溶剂,水做选择性溶剂,室温下自组装得到了稳定的聚集体溶液.扫描电镜和透射电镜观...     

Polyetherurethaneurea reinforced poly(vinyl alcohol) dialysis membranes: studies on permeability and mechanical strength

Poly(vinyl alcohol) is a hydrogel which is extensively studied for a variety of biomedical applications. Membranes developed from crosslinked poly(vinyl alcohol) (PVA) is having excellent permeability to solutes. However its wet breaking strength is low. Polyetherurethaneurea (PEUU), having an excellent mechanical strength is blended with PVA as a reinforcement, and membranes developed are studied for its permeability and mechanical strength. The optimum membrane selected, is having permeability and wet breaking strength almost equal to the commercially available cellulose acetate membrane.     

ZIF-8/PVA静电纺丝膜的制备及其吸附性能

采用静电纺丝技术成功制备出沸石咪唑骨架材料(ZIF-8)/聚乙烯醇(PVA)静电纺丝膜。分别探究和优化了PVA浓度、纺丝电压、接收距离等参数对纤维膜形态结构的影响。对复合纳米纤维膜进行了形貌表征和成分分析。实验发现在ZIF-8的浓度为10wt%条件下,当PVA的浓度为7wt%、电压为40kV、接收距离为16cm时,可得到可纺性最好、形态均匀的纳米纤维膜,膜纤维的平均直径在240nm左右。将已经制备成功的ZIF-8/PVA复合纳米纤维用于吸附刚果红,在12h内吸附容量可达86mg/g,显示出良好的吸附能力。     

Electrospun Proficient Polymer Based Nano Fibers with Ceramic Particles

Cobaltite of magnesium, embedded in polyvinylpyrrolidone (PVP) polymeric fibers forming nanocomposite were synthesized by combining conventional sol-gel method with electrospinning method. Ultrathin diameter polymer fibers containing nanoregime ceramic particles were obtained by varying various process parameters like voltage, concentration, feed rate, distance between nozzle tip and base plate on an indigenously assembled electrospinning unit. Polyvinylpyrrolidone (PVP) and polyvinylalcohol (PVA) polymeric fibers in nanoregime were also synthesized separately and the effect of the process parameters was observed on the fiber thickness and continuity. Characterization was done to verify the synthesis parameter effect on structural morphology of polymer based nanofiber composite. Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were used as tools for study of structural morphology and its correlation with process parameters.     

Fabrication of novel nanofiber scaffolds from gum tragacanth/poly(vinyl alcohol) for wound dressing application: In vitro evaluation and antibacterial properties

Gum tragacanth (GT) is one of the most widely used natural gums which has found applications in many areas because of its attractive features such as biodegradability, nontoxic nature, natural availability, higher resistance to microbial attacks and long shelf-life properties. GT and poly(vinyl alcohol) (PVA) were dissolved in deionized water in different ratios i.e., 0/100, 30/70, 60/40, 50/50, 40/60, 70/30, 0/100 mass ratio of GT/PVA. Nanofibers were produced from these solutions using electrospinning technique. The effect of different electrospinning parameters such as extrusion rate of polymer solutions, solution concentration, electrode spacing distance and applied voltage on the morphology of nanofibers was examined. The antibacterial activity of nanofibers and GT solution against Staphylococcus aureus and Pseudomonas aeruginosa was examined and these nanofibers showed good antibacterial property against Gram-negative bacteria. FTIR data showed that these two polymers may be having hydrogen bonding interactions. DSC data revealed that the exothermic peak at about 194 °C for PVA shifted to a lower temperature in GT/PVA blend. Human fibroblast cells adhered and proliferated well on the GT/PVA nanofiber scaffolds. MTT assay was carried out on the GT/PVA nanofiber to investigate the proliferation rate of fibroblast cells on the scaffolds.     

氧化石墨烯/聚乙烯醇复合材料的纳米压痕实验及力学性能

为了研究氧化石墨烯(GO)对聚合物基复合材料力学性能的影响,通过溶液混合法制备了GO/聚乙烯醇(PVA)复合材料。然后,采用XRD、TEM、FTIR、DSC和纳米压痕实验等研究了GO/PVA复合材料的结构、界面结合性能、力学性能、蠕变行为和吸水膨胀率。结果表明:GO可以均匀分散在PVA基体中,二者之间主要通过氢键作用结合,具有较高的界面结合力;与纯PVA相比,1wt% GO/PVA复合材料的硬度和有效弹性模量分别提高了28.9%和23.3%,压入蠕变深度下降了19.8%;GO/PVA复合材料具有较低的无限剪切模量与瞬时剪切模量比,表明GO提高了PVA的蠕变抗力;GO的添加同时增加了GO/PVA复合材料的阻水性并降低了膨胀系数。吸湿纳米压痕实验结果表明:纯PVA的力学性能会随吸湿时间延长而下降,而GO/PVA复合材料吸湿72h后的力学性能基本保持不变。所得结论为石墨烯增强聚合物基复合材料的研究提供了理论指导。      

聚乙烯醇模板中原位水热法羟基磷灰石纳米颗粒的控制制备及表征

具有生物活性和生物相容性的羟基磷灰石/高分子复合材料的合成和可控制备,是当今生物材料领域研究的重要热点,在生物可降解聚乙烯醇高分子模板中,采用原位水热法,系统研究了具有生物活性的纳米HAP的可控制备,并对水热时间和模板剂浓度对羟基磷灰石/聚乙烯醇复合材料中HAP微粒形貌、大小的影响进行系统研究.结果表明,水熟时间从0h增加到16h,PVA/HAP微粒中HAP形貌逐渐由不规整的球状、短棒状变为规整的长棒状,水热时间从16h增加到72h,长棒状的PVA/HAP微粒的形貌变化不大;模板高分子(聚乙烯醇)浓度越大,获得的HAP微粒越小.     

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.