壳聚糖/聚乙烯醇/壳寡糖抑菌纳米纤维膜的制备和性能研究

以壳聚糖（CS）为基材，使用静电纺丝的方法制备了搭载壳寡糖（CHOS）的CS/聚乙烯醇（PVA）/CHOS纳米纤维膜，并对纳米纤维膜的微观形貌、结构、抑菌性、亲水性以及溶解性能进行了研究。研究发现：CS/PVA/CHOS纳米纤维膜具备均匀密致的微观形貌；FT-IR测试表明，CHOS以物理混合的形式分散在CS/PVA/CHOS纳米纤维膜中；XRD测试表明，CHOS的加入改变了纳米纤维膜的结晶性，促进了各组分之间的相容性；水接触角测试表明纳米纤维膜具备良好的亲水性，在m（CS）：m（PVA）：m（CHOS）=20：80：10时，CS/PVA/CHOS纳米纤维膜的接触角相比于m（CS）：m（PVA）=20：80的CS/PVA纳米纤维膜由59.8°下降到37.5°；抑菌性能和溶解性能测试表明，m（CS）：m（PVA）：m（CHOS）=20：80：10时的CS/PVA/CHOS纳米纤维膜相比于未搭载CHOS的CS/PVA纳米纤维膜，抑菌性提升了38.9%，溶解率提升了38.6%。     

PVA/锑搀杂二氧化锡纳米复合材料的结构与性能研究

采用溶液共混的方式制备聚乙烯醇/锑搀杂二氧化锡(PVA/ATO)纳米复合材料,采用红外光谱(FTIR)、差示扫描量热仪(DSC)、光学显微镜、扫描电镜对复合材料的结构及微观形态进行了表征,对复合材料的导电性能及机械性能进行了测试。结果表明:PVA与ATO之间在共混膜中存在强烈的相互作用,这种相互作用可使纳米ATO在PVA基体中分散良好,在ATO含量较低的情况下就可获得导电性能及机械性能良好的复合材料;纳米ATO明显的异相成核效应,能够提高PVA的结晶温度及熔融温度。     

新型壳聚糖改性天然橡胶纳米纤维的制备与性能研究

本研究工作的目的是制备和表征环氧化天然橡胶-g-壳聚糖(ENR-g-CTS)/聚乙烯醇(PVA)复合材料纳米纤维。用静电纺丝技术制备了ENR-g-CTS/PVA复合材料纳米纤维,并用SEM、TEM和AFM方法观察ENR-g-CTS/PVA复合材料纳米纤维的微观形态。PVA纳米纤维和ENR-g-CTS/PVA复合材料纳米纤维的平均直径分别为约250和144 nm。与纯环氧化天然胶(ENR)相比,ENR-g-CTS在自然环境条件下的分解效果更好。此外,透过由ENR-g-CTS/PVA复合材料制备的载体膜,CSC释放20小时后的最大累积释放量达到18%。     

原位复合法制备磁性纤维素纤维及其性能研究

以天然棉纤维为基材,用原位复合法在上沉积磁性Fe3O4纳米粒子,制备出磁性纤维素纤维,利用X射线衍射仪、傅立叶变换红外光谱仪、扫描电子显微镜等方法对所得产物中磁性粒子进行表征。探究了预处理方法以及铁离子（Fe^3＋/Fe^2＋=2）浓度对制得的纤维磁性能的影响,并对磁性纳米粒子与纤维的结合牢度进行了讨论。结果表明：两个因素均会对纤维的磁性能产生影响,当用5%Na OH处理棉纤维原料,在铁离子总浓度为0.10 mol/L（Fe^3＋/Fe^2＋=2）反应时,最有利于磁性纳米颗粒在其表面的沉积,制得棉纤维复合材料的磁性能可以达到11.90 eum/g;经多次洗涤后磁性纤维的磁性能稍有下降,说明磁性纳米粒子对纤维附着力较好,期望被用作功能材料。     

豆荚结构聚乙烯醇缩丁醛/氧化铝复合相变纤维的制备及性能

利用微流控技术成功制备了聚乙烯醇缩丁醛（PVB）基材中共混氧化铝（Al₂O₃）纳米颗粒，其内部包封正十五烷的豆荚结构复合相变纤维。系统考察了Al₂O₃的含量对复合相变纤维的微观结构、相变性能和导热性能的影响规律。研究结果表明，复合相变纤维的致密表面可将正十五烷良好地包封于其内部的独立腔室内，包封率约为30%。在PVB基材中添加Al₂O₃纳米颗粒对复合相变纤维的豆荚结构和相变焓均无明显影响，但可显著提高相变纤维的导热性能。在模拟太阳光照射下，添加10% Al₂O₃纳米颗粒的复合相变纤维的表面温度比不含Al₂O₃纳米颗粒的相变纤维的表面温度升高更快，前者的熔融时间比后者缩短了25%。研究结果将为制备结构可控、具有良好、稳定导热性能和高效、快速调温性能的相变纤维提供重要的实验参考和指导。     

原位聚合制备PET/ATO纳米复合材料及其结晶行为

将锑掺杂二氧化锡(ATO)纳米颗粒均匀分散于乙二醇(EG)介质中,通过EG与对苯二甲酸(TPA)原位聚合制备了聚对苯二甲酸乙二酯(PET)/ATO纳米复合材料.利用SEM、DSC、XRD、FTIR和TGA等方法,研究了ATO在PET基体中的分散性、PET/ATO复合材料的结晶行为和热性能.利用原位聚合制备的PET/ATO复合材料,ATO颗粒在PET基体中分散均匀,尺寸100～150 nm,纳米ATO颗粒的加入导致PET的特性粘数增大.在PET基体中,纳米ATO颗粒起到异相成核的作用,提高了PET的结晶速率和结晶度,减小了PET的晶粒尺寸,同时也使PET热稳定性提高.随着ATO含量增加,熔融纺丝得到的PET纤维的电阻下降.加入1%ATO的PET纤维的体积电阻率为4.9×109 Ω·cm,具有很好的抗静电效果.     

香芹酚/明胶/聚乙烯醇纤维膜的制备 及其抗氧化性能

为了实现香芹酚（CAR）的缓释，减缓食品的氧化变质进程，以可降解聚合物明胶（GEL）和聚乙烯醇（PVA）为基材，CAR为抗氧化剂，采用静电纺丝法制备香芹酚/明胶/聚乙烯醇复合纤维膜（CAR/GEL/PVA纤维膜）。通过SEM、FTIR、XRD对纤维膜的结构进行表征，并测定了纤维膜的抗氧化活性、缓释性能和橄榄油的过氧化值；考察了CAR添加量（以溶液中GEL的质量为基准）对纤维膜结构和性能的影响。结果表明：随着CAR添加量的增加，纺丝溶液的黏度增加，电导率下降，所制备的纤维膜形貌由直径较小且分布均匀转变为直径较大且分布不均匀，从而影响纤维膜的力学性能、抗氧化性能和缓释效果。Ritger-peppas和Weibull模型能较好地拟合缓释过程，其相关系数接近于1，释放规律遵循Fickian扩散机制，且当CAR添加量为5%时，纤维膜的缓释效果最佳。高CAR添加量的CAR/GEL/PVA纤维膜能在油脂类食物中缓慢释放，具有较强的抗氧化活性。在48 h时，CAR添加量为20%的纤维膜的DPPH自由基清除率为82.4%，比未添加CAR纤维膜提升了50.4%，可以有效降低橄榄油的过氧化值。     

钢-PVA混杂纤维水泥基复合材料抗压力学性能及经济性研究

纤维增强延性水泥基材料(ECC)造价昂贵,在实际工程应用中尚未被推广。在传统ECC体系中加入钢纤维,并按照不同体积分数(0%、25%、50%、75%、100%)将国产PVA纤维替代日产PVA纤维,制备极具性价比的钢-PVA混杂纤维增强延性水泥基材料,通过立方体轴心抗压试验研究混杂纤维延性水泥基材料的单轴受压力学性能。结果表明：随着国产PVA纤维的增加,钢-PVA混杂纤维水泥基复合材料的抗压强度先减小后增加,抗压韧性指数先增强后减弱,而峰值应变提升效果较为显著;相较于普通水泥基材料,钢-PVA混杂纤维水泥基复合材料具有更好的完整性和延性;综合材料抗压性能与材料造价,国产PVA纤维替代日产PVA纤维配制钢-PVA混杂纤维水泥基复合材料可以实现功能价值和经济价值的协同最大化。     

PVC复合膜（片）的应用与开发

材料的复合可提高其综合性能，节约资源拓宽应用领域。ＰＶＣ昨合膜（片）是以单层膜（片）与薄型基材经复合成型加工的很有发展前途的复合材料之一。本文就ＰＶＣ复合膜（片）的应用与开发进行讨论。     

聚乙烯醇/壳聚糖复合电纺纤维膜的制备及表征

利用静电纺丝法制备了聚乙烯醇PVA/壳聚糖CS纳米纤维复合膜,并采用戊二醛蒸气对其交联处理。通过扫描电子显微镜(SEM)观察探讨了不同质量配比、助纺剂的添加以及电纺环境条件对复合纤维膜纤维直径及表面形貌的影响。通过傅里叶变换红外光谱(FTIR)对PVA/CS复合纳米纤维膜做了特征官能团分析,并对其热力学性能及其耐水性进行了表征。结果表明滴加7%(V/V)二甲基亚砜、0.5%(V/V)丙三醇、0.5%(V/V)吐温80的3%(V/V)的乙酸为溶剂,PVA和CS质量配比为90/10,环境湿度0±15%电纺条件下制备的复合纤维形态均一,无珠串无液滴;FTIR研究显示,复合纤维的两种组分发生一定的相互作用,成功制备了戊二醛交联PVA/CS纳米纤维膜;热重(TG)、差热(DSC)结果都进一步说明CS和PVA之间形成氢键,戊二醛交联后复合纤维的热稳定性进一步增强。交联前后纤维膜的耐水性结果表明交联后的共混纤维膜有良好的抗溶解性,在水中可以很好的保持纤维的结构。     

Electrospinning fabrication and characterization of poly(vinyl alcohol)/waterborne polyurethane nanofiber membranes in aqueous solution

Poly(vinyl alcohol) (PVA)/waterborne polyurethane (WBPU) nanofiber mats were prepared using electrospinning method with aqueous solutions. Scanning electron microscopy (SEM), X‐ray diffraction (XRD), thermal gravimetric analyzer (TGA), and tensile strength testing machine (ZWICK) were used to characterize the morphology and properties of the PVA/WBPU nanofiber mats. The results showed that the morphologies of PVA/WBPU nanofiber mats changed with the total solid concentration and the mass ratio of PVA/WBPU in the spinning solution. The tensile strength and thermal stability of the fibers could be significantly affected by the WBPU contents. The electrospun PVA/WBPU membranes showed higher water uptake, which would have potential applications in wound dressings. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Ultrasmall Ag nanocrystals supported on chitosan/PVA nanofiber mats with bifunctional properties

Bifunctional nanofiber mats consisting of chitosan (CS), poly(vinyl alcohol) (PVA), and silver nanocrystals (Ag NCs) have been fabricated by a facile electrospinning method. The formation and presence of Ag NCs supported on CS/PVA nanofibers are confirmed by ultraviolet‐visible spectroscopy and X‐ray diffraction. The morphology of the samples is characterized by transmission electron microscopy and scanning electron microscopy. The prepared Ag NCs/CS/PVA nanofiber mats show pronounced antibacterial activity against Escherichia coli and excellent filtration property for suspended particulate matter (SPM) particles. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46504.     

ATO/PU复合隔热膜的制备及其性能研究

氧化锡锑(ATO)具有良好的红外阻隔性。将ATO直接分散到异氰酸酯中,与聚醚二元醇及催化剂制备含ATO的预聚物,再采用小分子扩链剂制备ATO/PU复合隔热膜。讨论了ATO在预聚物中的分散稳定性、ATO/PU复合隔热膜的基本物理性能和隔热性能。结果表明,平均粒径为32.9μm的ATO粒子在黏度57.86 Pa·s的预聚物中的沉降速度是4.84×10^-9 m/s,可以在预聚物中稳定地分散。当ATO质量分数为0.097%时,ATO/PU复合隔热膜的拉伸强度为26.8 MPa;在400~800 nm波段范围内可见光透过率和在800~2500 nm波段范围内近红外光的透过率分别为68.02%和27.06%;与不含ATO粒子的聚氨酯材料相比,该材料隔热温差达14℃,具有优良的隔热效果。     

Electrospinning fabrication and characterization of poly(vinyl alcohol)/montmorillonite nanofiber mats

Poly(vinyl alcohol) (PVA)/montmorillonite clay (MMT) nanofiber mats have been fabricated by the electrospinning technique. The PVA/MMT nanofiber mats were characterized by X‐ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and mechanical measurements. The study showed that the introduction of MMT results in improvement in tensile strength, and thermal stability of the PVA matrix. XRD patterns and SEM micrographs suggest the coexistence of exfoliated MMT layers over the studied MMT contents. FTIR revealed that there might be possible interaction occurred between the MMT clay and PVA matrix. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Improvement in nanofiber filtration by multiple thin layers of nanofiber mats

Nanofiber filtration is drawing great interest nowadays because of its large surface collection area as well as low air resistance. In this study, electrospun nanofiber mats of different thicknesses were evaluated for their filter quality factors. Shorter-term electrospun fiber mats exhibited a better quality factor than those longer-term electrospun ones. Multiple thin layers of nanofiber mats to improve the filter quality of the nanofiber filters were then evaluated. Filtration test results showed that the filter made up of multiple thin layers of nanofiber mats had a filter quality factor much higher than the single thick layer nanofiber mat. Better thickness uniformity in the multi-layer structure due to stacking compensation and smaller fiber diameters in nanofibers of short-term deposition time are two possible reasons for the improvement of the filter quality.     

加盐提高聚乙烯醇纳米纤维膜的力学和热稳定性能

对含有NaCl、KCl、Na2SO4、Na2CO3的聚乙烯醇(PVA)溶液进行静电纺丝,成功制备出含盐PVA纳米纤维膜。通过扫描电子显微镜(SEM)对各纤维膜的形貌进行表征,发现这些无机盐的加入对PVA纳米纤维的形貌造成明显影响,如纤维之间发生粘连或扁平带状纤维。此外通过单轴拉伸对各纤维膜的力学性能进行测试,结果表明:少量NaCl、KCl、Na2SO4或Na2CO3的加入,可以明显提高PVA纳米纤维膜的力学性能。进一步通过热失重分析(TGA)对各纤维膜热稳定性的考察表明:NaCl、KCl、Na2SO4的加入可以有效提高PVA纳米纤维膜的热稳定性,而Na2CO3的加入则对PVA纳米纤维膜的热稳定性无明显提高。     

丝素蛋白-聚乙烯醇共混改性电纺膜的制备

采用静电纺丝技术,以特殊设计的金属丝螺旋盘绕滚筒作为接收装置,制备了具有一定取向的丝素蛋白(SF)-聚乙烯醇(PVA)共混纳米纤维材料。利用扫描电子显微镜(SEM)对纤维形貌进行观察,并通过Image-Pro Plus软件对纤维细度进行测试,探讨了SF与PVA的配比以及纺丝电压、接收距离等静电纺丝参数对所得纳米纤维形貌、细度及其分布的影响。结果表明:将质量浓度为25 kg/L的SF与质量分数为8%的PVA以质量比15∶3.2共混,并采用20 kV的纺丝电压和13 cm的接收距离静电纺时,所得纳米纤维的平均直径约为238 nm,且直径分布较为均匀。采用该法制得的纳米纤维材料具有一定的纤维取向,有利于细胞生长,可应用于生物医药领域。     

ITO electrode modified by self-assembling multilayer film of polyoxometallate on poly(vinyl alcohol) nanofibers and its electrocatalytic behavior

Poly(vinyl alcohol) (PVA) nanofiber mats were collected on indium tin oxide (ITO) substrate by electrospinning method. A multilayer film composed of α-[P₂W₁₈O₆₂]⁶⁻ (abbr. P₂W₁₈), a polyoxometallate (POM) anion, and poly(diallymethylammonium chloride) (abbr. PDDA) was fabricated by layer-by-layer (LBL) self-assembly technique on the PVA/ITO electrode. The PDDA/P₂W₁₈ multilayer film could be unselectively or selectively deposited on the PVA/ITO electrode via changing the amount of PVA nanofibers on the ITO substrate. The scanning electron microscope (SEM) images showed that when the electrospun time was short the PDDA/P₂W₁₈ multilayer film was unselectively deposited on PVA nanofiber mats because the amount of PVA nanofibers was too little to cover most of the ITO substrate. However, when the electrospun time was long enough, the PDDA/P₂W₁₈ multilayer film was selectively deposited on PVA nanofiber mats because of the larger surface area and higher surface energy of PVA nanofibers in comparison with the flat ITO substrate. Growth process of the multilayer film was determined by cyclic voltammetry (CV). Electrocatalytic effects of the PDDA/P₂W₁₈ multilayer film unselectively and selectively deposited on the PVA/ITO electrode on NO₂⁻ were observed.     

Covalent immobilization of α‐amylase onto thermally crosslinked electrospun PVA/PAA nanofibrous hybrid membranes

Poly(vinyl alcohol)/poly(acrylic acid) (PVA/PAA) nanofibers with the fiber diameter of 100–150 nanometers were fabricated by electrospinning. PVA/PAA nanofibers were crosslinked by heat‐induced esterification and resulting nanofiber mats insoluble in water. α‐Amylase was covalently immobilized onto the PVA/PAA nanofiber surfaces via the activation of amine groups in the presence of 1,1′‐carbonyldiimidazole. The immobilized α‐amylase has more resistance to temperature inactivation than that of the free form and showed maximum activity at 50°C. pH‐dependent activities of the free and immobilized enzymes were also investigated, and it was found that the pH of maximum activity for the free enzyme was 6.5, while for the optimal pH of the immobilized enzyme was 6.0. Reuse studies demonstrated that the immobilized enzyme could reuse 15 times while retaining 81.7% of its activity. Free enzyme lost its activity completely within 15 days. Immobilized enzyme lost only 17.1% of its activity in 30 days. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

X‐ray diffraction and dynamic mechanical analyses of α‐chitin whisker‐reinforced poly(vinyl alcohol) nanocomposite nanofibers

Electrospinning is a facile method for preparing nanocomposite materials in fiber form. Nanomaterials that have been incorporated within such fibers are usually inorganic in nature. Recently, nanocomposite nanofibers based on poly(vinyl alcohol) (PVA) as the matrix and nanocrystals of α‐chitin (i.e. chitin whiskers; ca 31 nm in width and ca 549 nm in length on average) as the nanofiller have been successfully prepared. In the study reported here, the fibers were further investigated using X‐ray diffraction (XRD) and dynamic mechanical analyses in comparison with the corresponding solvent‐cast films. The average diameters of the PVA/chitin whiskers fibers ranged between 175 and 218 nm. Careful analysis of the wide‐angle XRD patterns of the fiber mats and the films showed that PVA was partially crystalline, and the incorporation of the whiskers within the fibers was confirmed by peaks characteristic to α‐chitin crystals. Dynamic mechanical analysis showed that the fiber mats were weaker than the films and that the relaxation temperatures associated with the glass transition (T_g) of the fiber mats were greater than those of the films. The addition and increasing the amount of the whiskers caused the crystallinity of PVA within the nanocomposite materials to decrease and T_g to increase. The present study shows that the geometry of nanocomposite materials plays a major role in determining their properties. Copyright © 2009 Society of Chemical Industry