静电纺丝制备PEI/PVA超细纤维负载纳米铑杂化材料的研究

利用NaBH4作为还原剂,表没食子儿茶素没食子酸酯(EGCG)为稳定剂,还原RhCl3水溶液制备铑纳米颗粒,并用透射电镜(TEM)研究了铑纳米颗粒的形貌.通过静电纺丝技术制备了PEI/PVA纳米纤维,并用戊二醛作为交联剂使之交联以提高其耐水性.然后在交联过的PEI/PVA纤维膜上负载铑纳米颗粒;利用傅里叶红外光谱仪(FTIR)、扫描电子显微镜(SEM)对PEI/PVA以及Rh/PEI/PVA薄膜进行了表征.结果表明:利用静电纺丝技术和复合技术可以制备PEI/PVA超细纤维负载纳米铑的杂化材料.     

PVA/PEI超细纤维负载纳米钯杂化材料的制备

通过静电纺丝技术制得了聚乙烯醇(PVA)/聚乙烯亚胺(PEI)超细纤维膜,使用戊二醛蒸汽交联使其具有水稳定性,进而将交联后的PEI/PVA超细纤维膜浸入PdCl2溶液中至吸附平衡,以硼氢化钠(NaBH4)为还原剂,于超细纤维膜表面原位合成Pd纳米粒子.用场发射扫描电子显微镜(FE-SEM)、傅里叶变换红外(FTIR)、紫外可见分光光度计(UV)等技术表征了PVA/PEI超细纤维,交联后的PEI/PVA超细纤维膜及负载有Pd纳米粒子的PEI/PVA超细纤维膜.研究表明:交联后的PVA/PEI超细纤维膜具有良好的水相稳定性,Pd纳米粒子在PVA/PEI超细纤维膜表面均匀分布,负载有Pd纳米粒子的PEI/PVA超细纤维膜对Cr(Ⅵ)的还原反应具有良好的催化性能.     

二硫化钼/聚丙烯腈复合纳米纤维膜的制备及其光催化性能

采用水热合成法制备了无机半导体光催化剂二硫化钼(MoS_2),利用静电纺丝技术,将MoS_2粉末添加到不同质量分数的聚丙烯腈(PAN)溶液中进行共混纺丝,制备MoS_2/PAN复合纳米纤维膜,并用于罗丹明B溶液的催化降解。借助扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X-射线衍射(XRD)等对纳米纤维膜的形貌和性能进行表征。结果表明:MoS_2/9%PAN复合纳米纤维膜中的纳米纤维形貌较好,直径较均匀,MoS_2在纳米纤维上的分布也较为均匀;使用其对30 mL的10 mg/L罗丹明B溶液进行光催化降解,光催化效果好,降解率达89.8%,重复使用3次后,降解率仅下降了2.3%,表现出良好的循环使用性。     

聚乙烯醇双酶降解工艺条件优化

作为纺织和造纸工业中的重要污染物,聚乙烯醇(PVA)的高效降解广受关注。为提高PVA的降解效率,本研究中对PVA脱氢酶(PVADH)和氧化型PVA水解酶(OPH)降解PVA的工艺条件进行了优化。通过Box-Behnken实验和响应面分析,确定PVA双酶降解的反应条件为:PVA 1 g/L,PVADH 123 U/mL,OPH 12 U/mL,pH 7.7,酶解温度41℃,Ca~(2+)浓度1 mmol/L,PQQ浓度6μmol/L。在该条件下PVADH和OPH共同催化4 h,PVA降解率达到95%以上。上述结果表明,PVADH和OPH双酶能有效降解PVA。研究结果将促进酶法降解PVA的工业化应用。     

再生丝素蛋白/纳米铯钨青铜杂化纤维的制备及性能研究

文章以纳米铯钨青铜颗粒(Cs_xWO_3NPs)作为共混剂对再生丝素蛋白(RSF)进行改性,通过湿法纺丝制备了不同含量比的RSF/Cs_xWO_3NPs杂化纤维。FT-IR和XRD结果表明,Cs_xWO_3NPs的加入降低了RSF的结晶度和内部晶粒体积。3%-RSF/Cs_xWO_3NP杂化纤维的断裂强度、断裂伸长率和断裂能分别可达(233.41±19.45) MPa、(119.63±12.59)%和(171.21±17.17) MJ/m~3,相较于空白RSF分别增加了55.6%、125.9%、194.2%。光照测试结果表明,RSF/Cs_xWO_3NPs杂化纤维比空白RSF织物的温度上升得更快,其平均温度在1 min内从30.7℃达到52.2℃,在10 min内达到76.7℃。研究结果表明:Cs_xWO_3NPs能够提高RSF纤维的韧性,RSF/Cs_xWO_3NPs杂化纤维具有良好的力学性能和光热性能,在光致发热功能性纤维和织物方面具有良好的应用潜力。     

静电纺丝制备ZnO纳米纤维及光催化性能的研究

ZnO作为一种n型半导体,有较高的研究和应用价值。本实验结合静电纺丝技术和煅烧工艺,利用DMF、PVP、乙酸锌为前驱体,采用静电纺丝法制备不同温度下的ZnO纳米纤维材料。利用X-射线衍射仪(XRD)、紫外-可见漫反射光谱(UVVis DRS)表征样品和光催化性能。以金卤灯和氙灯分别模拟太阳光,罗丹明B为目标降解物,在不同光照射下,不同温度的ZnO纳米纤维材料对罗丹明B的光催化降解效率不同。金卤灯照射150min时,550℃煅烧的ZnO对罗丹明B的降解率最佳,达到96.3%;氙灯照射150min时,600℃煅烧的ZnO对罗丹明B的降解率最佳,达到93.0%,提高了对可见光的利用率。所制备的ZnO纳米纤维光催化剂在有机污染物的处理领域具有广阔的应有前景。     

羊毛角蛋白与PVA复合纤维膜的制备及其在医用口罩滤芯中的应用

对大量废弃的羊毛纺织品进行回收利用，提取角蛋白并将其与聚乙烯醇(PVA)制备成复合纤维膜，应用于医用口罩滤芯材料中。采用酸/碱等电点沉淀法制备羊毛角蛋白，离心提纯后与不同浓度的PVA共混配置纺丝溶液，利用静电纺丝法在医用口罩基底材料上喷制角蛋白/PVA纳米纤维膜。分别对试样进行电镜、红外光谱和粉尘过滤测试分析并比较不同角蛋白与PVA质量分数下纤维膜的物化性能差异。电镜实验结果表明：角蛋白质量分数一定时，当PVA质量分数越高，制备的纤维直径随之变大；PVA溶液质量分数一定时，随着角蛋白质量分数的提高，制备的纳米纤维的直径变小。红外光谱测试显示角蛋白与PVA通过氢键稳定的结合在一起。接触角测试显示加入角蛋白后能明显改善滤芯材料的亲水性。空气过滤效率测试表明，当PVA溶液质量分数为6%,角蛋白与PVA比为30∶70时，过滤效率最高，可达97.17%。     

Fe_2O_3/TiO_2异质结的制备及光催化降解性能

结合静电纺丝技术和水热法制备Fe_2O_3/TiO_2异质结光催化材料.利用扫描电镜(SEM)、X射线衍射(XRD)、傅立叶转换红外光谱(FT-IR)及比表面分析等方法,对Fe_2O_3/TiO_2异质结的形貌、晶型、化学组成等进行表征.利用Fe_2O_3/TiO_2材料对罗丹明B(RB)进行光催化降解,结果表明,Fe_2O_3/TiO_2对RB的降解速率高于纯TiO_2纳米纤维,而且掺铁量为0.5%时降解效果最好.     

Fe2O3/TiO2异质结的制备及光催化降解性能

结合静电纺丝技术和水热法制备Fe2O3/TiO2异质结光催化材料.利用扫描电镜(SEM)、X射线衍射(XRD)、傅立叶转换红外光谱(FT-IR)及比表面分析等方法,对Fe2O3/TiO2异质结的形貌、晶型、化学组成等进行表征.利用Fe2O3/TiO2材料对罗丹明B(RB)进行光催化降解,结果表明,Fe2O3/TiO2对RB的降解速率高于纯TiO2纳米纤维,而且掺铁量为0.5%时降解效果最好.     

SA/PVA液芯微囊化细胞的制备工艺及其催化性能的考察

为了进一步提高产紫青霉菌(Penicillium purpurogenum Li-3)表达的β-葡萄糖醛酸苷酶(β-glucuronidase,β-GUS)定向催化甘草酸(Glycyrrhizic acid, GL)生成单葡萄糖醛酸基甘草次酸(Glycyrrhetinic acid monoglucuronide, GAMG)的能力,本文以海藻酸钠/聚乙烯醇为固定化材料,采用微胶囊固定化技术对产紫青霉细胞进行了研究。结果表明:当海藻酸钠浓度为1%,聚乙烯醇为6%,氯化钙浓度为2%,加菌量为5%,固化氯化钙浓度为2%,并置于-18℃冰箱内冷冻4 h时,SA/PVA液芯微囊化细胞的催化活性最高,且机械强度较好。通过测定GL在SA/PVA液芯微囊化细胞中的扩散性能,建立传质模型计算得到GL在SA/PVA液芯微囊化细胞中的传质系数k=0.0741。将SA/PVA液芯微囊化细胞采用摇床培养连续培养19次,仍能保持62.02%的活性。采用SA/PVA液芯微囊化技术制备生物微胶囊能明显提高β-GUS的稳定性和重复利用率,有利于应用于工业生产中。     

Cd2+-PVA/PA6金属配合纳米纤维的制备及反应动力学分析

 利用静电纺丝技术得到PVA/PA6复合纳米纤维,并将其与镉离子（Cd2+）溶液反应,制备Cd2+-PVA/PA6金属配合纳米纤维。采用原子吸收光谱（AAS）测定金属离子浓度,用傅里叶红外光谱(FTIR)对PVA/PA6复合纳米纤维和Cd2+-PVA/PA6金属配合纳米纤维的相应吸收峰进行分析,用扫描电子显微镜（SEM）对其形貌进行表征。结果表明,PVA/PA6纳米纤维具有优异的金属离子配合性能和良好的形态稳定性。同时研究了金属离子吸附过程及动力学参数,得出吸附常数K_l=0.0257 L/mmol、饱和离子配合量Q_m=4.4643 mmol/g,相关系数R²=0.997,该反应过程符合兰格缪尔吸附模型。     

静电纺丝法制备木质素基纳米纤维

以N,N-二甲基甲酰胺为溶剂,对不同比例的乙酸木质素（AAL）与聚乙烯吡咯烷酮（PVP）混合溶液,AAL与聚丙烯酸酯（polyacrylate）混合溶液,AAL与聚乙烯醇（PVA）混合溶液三种溶液体系进行静电纺丝。用扫描电子显微镜观察了纳米纤维的表面形貌。结果表明：AAL与PVA混合溶液通过电纺不能得到纳米纤维。通过电纺可以得到直径均匀、表面光滑的AAL与PVP混合纳米纤维,AAL与聚丙烯酸酯混合纳米纤维,并且AAL含量的增加对混合纳米纤维的直径和表面形貌没有明显的影响。进而对单一AAL的静电纺丝进行了研究,分别研究了THF,DMF,乙酸等不同的溶剂体系,发现只有以乙酸为溶剂才能电纺成纤。     

交联PVA与未交联PVA纳米纤维膜的结构比较

利用静电纺丝法制备交联PVA纳米纤维和未交联PVA纳米纤维,对其制作工艺、结构等进行了比较。在硫酸作为催化剂的条件下,PVA纤维能有效通过顺丁烯二酸酐（MA）进行交联。采用扫描电镜法（SEM）、红外光谱法（FTIR）、差热扫描法（DSC）对PVA粉末、未交联PVA纳米纤维膜以及交联PVA纳米纤维膜的形态和结构进行了研究。     

Electrospinning as a novel strategy for the encapsulation of living probiotics in polyvinyl alcohol/silk fibroin

The probiotic Lactobacillus plantarum (L. plantarum) were encapsulated with polyvinyl alcohol (PVA) and polyvinyl alcohol/silk fibroin (PVA/SF) nanofibers by electrospinning, respectively. Actually, different concentrations of PVA and SF have significant influence on the morphology of nanofibers, the optimized condition is 6% (w/w) SF and 8% PVA mixed. The L. plantarum on the nanofibers were characterized by scanning electron microscopy (SEM). The different features of PVA/L. plantarum and PVA/SF/L. plantarum nanofibers were proved by thermogravimetric (TGA) and Fourier transform infrared spectroscopy (FTIR). Microbiological tests showed that PVA/SF/L. plantarum exhibited increased survival rates evidently, after being treated in artificial gastric juice at 37 °C for 2 h, and the optical density (OD) value in stable growth period was 2.75, compared with free L. plantarum. The results of this study suggest a novel encapsulation approach that protects probiotic cells during their exposure to adverse environmental and intestinal conditions.     

Synthesis and in vitro antimicrobial characterization of Boron-PVA Electrospun nanofibers

Polyvinyl alcohol (PVA) electrospun nanofibers and boric acid (BA) complexes of these nanofibers were synthesized with and without using TritonX-100(TX-100) as a water soluble surfactant (PVA, PVA/BA, PVA/TX-100, PVA/TX-100/BA). The electrospun nanofibers were characterized by SEM, FTIR and TGA. Preliminary results showed that certain amount of boric acid decreased the number of Stapylococcus aureus from 6,8x10⁷(CFU/mL) to 3x10⁷(CFU/mL). In the preparation of polymer, boric acid was used as a crosslinker and antimicrobial agent whereas TX-100 was used as surfactant. The viscosity and conductivity measurements indicated that the BA increased viscosity but decreased conductivity. In contrast, TX-100 increased conductivity without considerable effect on viscosity, which affects the production and resulting nanofiber properties such as diameter and bead formation. The antimicrobial activities of the nanofibers were assayed in vitro by Gram-negative (E. coli) and Gram-positive(S. aureus) bacteria. It was observed that PVA/TX-100/BA showed better antibacterial activity against S.aureus bacteria compared to PVA and PVA/TX-100 nanofibers.     

乳液静电纺丝美藤果油/聚乙烯醇纳米纤维膜的制备及性能

采用乳液静电纺丝法制备基于美藤果油/聚乙烯醇（polyvinyl alcohol,PVA）乳液的具有核壳结构的纳米纤维及纤维膜,为促进美藤果油在食品领域的进一步应用提供基础,并促进美藤果油作为新资源食品的高值化利用。通过电导率仪和黏度计测定乳液的电导率和黏度,利用扫描电子显微镜和透射电子显微镜观察纳米纤维膜形貌,并对乳液组分比例、纺丝参数进行调整优化;通过热特性和傅里叶变换红外光谱表征分析纳米纤维膜的各组分及作用;利用接触角测量仪测试纳米纤维膜表面的亲水性能;使用抗拉强度测量仪测定纳米纤维膜的机械性能。结果表明：制备美藤果油/PVA纤纳米纤维膜的乳液最佳配比为PVA质量分数14%,美藤果油、PVA、吐温-80的最佳质量比为5∶14∶1;最佳纺丝条件为电压25 kV、接收距离18 cm、供液速率1.0 mL/h。在最佳条件下纺丝,可得到平均直径为570 nm且形貌良好、分布均匀的纳米纤维。傅里叶变换红外光谱和热特性分析结果表明所制得的纳米纤维成功地封装了美藤果油,并在低于330 ℃的温度条件下表现出良好的热稳定性。接触角测量结果表明纳米纤维膜表面具有良好的亲水性能。机械性能分析结果表明美藤果油的添加可以提高纳米纤维膜的拉伸性能。     

预糊化对挤压吹塑制备淀粉/PVA纳米复合膜性能的影响

为了获得高性能的淀粉基复合膜,选取羟丙基交联淀粉(HP)和2种预糊化羟丙基交联淀粉(PC、PE)为成膜基材,分别与2种聚合度的PVA(1 700、2 400)复合,添加有机改性蒙脱土为增强剂,采用挤压吹塑法制备了淀粉/PVA纳米复合膜。结果表明:PC/PVA、PE/PVA复合膜表面不存在淀粉颗粒碎片,HP/PVA复合膜表面分布着未糊化的淀粉颗粒;同种淀粉和高聚合度的PVA之间,界面亲合力更强,相容性更好,形成的复合膜力学性能较好,疏水性能更强;预糊化淀粉有利于良好、有序插层结构的形成,与PVA分子之间联结更紧密,阻碍了水分子的吸附和透过。     

高阳电荷密度聚合物对高得率浆助留助滤性能的影响

采用改性聚乙烯亚胺(PEI)作为高得率浆中的阴离子垃圾捕捉剂,并与聚合氯化铝(PAC)和聚二甲基二烯丙基氯化铵(PDADMAC)等高阳电荷密度聚合物进行比较,探讨了PEI对高得率浆CPAM/膨润土体系助留助滤性能的影响。结果表明,相对分子质量大和阳电荷密度高的改性PEI作为阴离子垃圾捕捉剂可以显著改善CPAM或CPAM/膨润土体系对高得率浆的助留助滤性能。添加0.02%的PEI作为阴离子垃圾捕捉剂,CPAM用量为0.03%时,高得率浆的滤水速度和总留着率比CPAM单元体系分别提高了16.0%和1.9个百分点;比CPAM/膨润土微粒体系分别提高28.6%和3.0个百分点。     

Effect of Fe3O4 nanoparticles on magnetic electrospun nanofibers

A new simple magnetic electrospinning setup was devised to manufacture partially aligned nanofiber in the paper. Compared with the traditional electrospinning setup, a U-shaped permanent magnet was employed and applied with a slide rheostat. Polyvinyl alcohol (PVA) and PVA/Fe₃O₄ fibers were prepared by the magnetic electrospinning, respectively. The morphology and alignment of the fibers were characterized by the use of scanning electron microscopy (SEM). Results showed that the magnetic field could decrease the diameter of fibers and enhance the crystal conditions of fibers, and the addition of Fe₃O₄ nanoparticles improved the alignment of nanofibers.     

Electrospinning of Poly(vinyl alcohol) Nanofibers Loaded with Hexadecane Nanodroplets

Abstract: The feasibility of producing poly(vinyl alcohol) (PVA) nanofibers containing fine-disperse hexadecane droplets by electrospinning a blend of hexadecane-in-water emulsions and PVA was investigated. Hexadecane oil-in-water nanoemulsions (d₁₀= 181.2 ± 0.1 nm) were mixed with PVA at pH 4.5 to yield polymer-emulsion blends containing 0.5 to 1.5 wt% oil droplets and 8-wt% PVA. The solution properties of emulsions and emulsion-PVA blends (viscosity, conductivity, surface tension) were determined. Solutions were electrospun and the morphology and thermal properties of deposited fiber mats characterized by scanning electron microscopy and differential scanning calorimetry. Fiber mats were dissolved in buffer to liberate incorporated hexadecane droplets and the buffer solutions analyzed by optical microscopy, UV-spectroscopy, and light scattering. Analysis of dry fiber mats and their solutions showed that emulsion droplets were indeed part of the electrospun fiber structures. Depending on the concentration of hexadecane in the initial emulsion-polymer blends, droplets were dispersed in the fibers as individual droplets or in form of aggregated flocs of hexadecane droplets. Nanofibers with spindle-like perturbations or nanofibers containing bead-like structures with approximately 5 times larger than the size of droplets in the original nanoemulsion were obtained. Remarkably, incorporation of hexadecane droplets in fibers did not alter size of individual droplets, that is, no coalescence occurred. The manufacture of solid matrix containing nanodroplets could be of substantial interest for manufacturers wishing to develop encapsulation system for lipophilic functional compounds such as lipid-soluble flavors, antimicrobials, antioxidants, and bioactives with tailored release kinetics. Practical Applications: The paper describes the formation of electrospun nanofibers from hydrophilic polymers that contain fine-disperse emulsion droplets. By incorporating emulsion droplets, a large variety of lipophilic ingredients can be easily loaded into the fibers’ hydrophilic polymer matrix. This is of practical importance as to date the only way to include a lipophilic ingredient in a nanofibers is by dissolving the lipophilic ingredient and polymer in an organic solvent followed by electrospinning. However, use of an organic solvent is (a) not feasible if one wants to electrospin hydrophilic polymers, and (b) use of organic solvents is generally highly undesirable in the food industry. Our results should be of interest to a number of industries such as the food, pharmaceutical, chemical, and personal care industries that are generally in need of novel matrices that can serve as carrier vehicles and release functional components such as flavors, antimicrobials, antioxidants, drugs, and bioactives.