Composite Films Based on Polyvinyl Alcohol and Na-Carboxymethyl Cellulose for Separation

Russian Journal of Applied Chemistry - The possibility of using composite films based on polyvinyl alcohol (PVA) and Na-carboxymethylcellulose (Na-CMC) as a separating material is considered for...     

杂多酸/聚乙烯醇复合膜的制备及光催化性能研究

合成了过渡金属取代的硅钨酸盐K₆SiM(H₂O)W₁₁O₃₉(M=Co、Ni、Cu,简称为SiMW₁₁),利用硅钨酸(H₄SiW₁₂O₄₀·nH₂O,简称为SiW₁₂)与SiMW₁₁做母体,分别将它们负载于聚乙烯醇(polyvinyl alcohol,PVA)上,制成一系列杂多酸/聚乙烯醇复合膜光催化剂,利用IR、SEM进行了表征.以高压汞灯为光源,分别研究了SiW₁₂/PVA、SiCoW11/PVA、SiNiW₁₁/PVA、SiCuW₁₁/PVA复合膜对有机染料甲基橙的光催化脱色,它们都具有很高的催化活性,60 min内对甲基橙的脱色率均可达到90%以上,其中SiW₁₂/PVA复合膜效果最好,12 min内脱色率达100%.提高SiW₁₂负载量可有效提高膜的光催化活性,当SiW₁₂与PVA质量比为1:1时催化活性最高.     

Acetalization of Polyvinyl Alcohol Fiber with Aldehyde-containing Polyvinyl Alcohol Fiber

A procedure is proposed for preparing polyvinyl alcohol fiber with increased water absorption by acetalization of a freshly formed fiber with dialdehyde-containing polyvinyl alcohol fiber. The fiber characteristics were determined in relation to the acetalization conditions.     

Effect of Ion Hydration on the Degree of Swelling of a Crosslinked Polyvinyl Alcohol Gel

Russian Journal of Physical Chemistry A - The interaction of dissolved substances with polar groups of a hydrophilic polymer is analyzed. The effect of the size and hydration energy of cations of...     

聚乙烯醇膜耐水改性的研究进展

聚乙烯醇(PVA)作为一种广泛应用的水溶性高分子聚合物,具有较好的气体阻隔性、热稳定性、生物相容性,故以此基料的改性膜材料成为重要的研究方向。但是由于聚乙烯醇结构中含有大量的亲水性基团(—OH),导致成膜的耐水性差,这很大程度上限制了它的推广和应用。本文总结了国内外对聚乙烯醇膜耐水改性的方法,如酯化交联、羟醛缩合、复配增塑、纳米补强和共混杂化等,有利于进一步推进聚乙烯醇耐水改性的研究,为设计和制备高性能的聚乙烯醇膜提供一定的参考,并进一步拓展聚乙烯醇的应用范围。     

Anisotropic Swelling of Oblique-Deposited SiO/SiO2Films in Water Vapors

Due to anisotropic swelling of mixed SiO/SiO₂films induced by water adsorption, geometrically regular film buckling from the substrate was observed in the form of linear spatially periodical structures with longitudinal orientation. The mechanical stresses in these films and geometry of the formed structures were studied. A mechanism was proposed to describe the observed deformation effect.     

Swelling Kinetics of Interpenetrating Polymer Hydrogels Composed of Poly(Vinyl Alcohol)/Chitosan

Interpenetrating polymer network (IPN) hydrogels based on poly(vinyl alcohol)/chitosan were prepared by UV irradiation. The swelling behavior of the IPN hydrogels was studied by immersion of the films in deionized water at various temperatures and in buffer solutions at various pHs. IPN3 exhibited a relatively high swelling ratio. The swelling ratio increased with an increase in the content of chitosan and were higher in acidic rather than in alkaline pHs. The overall swelling process was anomalous diffusion due to polymer relaxation. The diffusion coefficient values increased with an increase in temperature and the content of chitosan.     

聚乙烯醇载银海绵的制备及界面光热驱动水蒸发性能

利用光热材料的太阳能水蒸发技术是一种绿色、 环保地解决淡水资源短缺的重要技术, 但光热材料的制备成本、 蒸发效率和热损失等因素限制了其推广应用. 本文采用一锅法制备了聚乙烯醇载银海绵(AgNPs/PVA)太阳能界面蒸发器, 并研究了AgNPs含量对AgNPs/PVA在太阳能驱动水蒸发过程中光热性能的影响. 研究结果表明, 当AgNPs的质量为PVA的10%时, 制备的AgNPs/PVA在1 kW/m ²的太阳光强度下具有最优的蒸发速率, 水蒸发速率可达1.62 kg?m ^?2?h ^?1, 为纯水(0.42 kg?m ^?2?h ^?1)的3.9倍. 本文制备的AgNPs/PVA具有制备工艺简单、 亲水性能优良和蒸发性能良好的特点, 在太阳能驱动水蒸发领域具有较大的应用前景.     

高吸水树脂的溶胀动力学

基于扩散-松弛模型,分别研究了树脂粒度和溶液浓度对高吸水树脂溶胀行为的影响。实验结果表明:水分子的扩散和树脂大分子链段的松弛对树脂的溶胀均有贡献,但两者贡献大小与树脂粒度和溶液浓度有关。     

聚乙烯醇缩对甲酰基偶氮氯膦的合成及其性质

首次报道了聚乙烯醇缩对甲酰基偶氮氯膦（简称：ＰＶ·ＣＰｐＦ）的合成、纯化及其鉴定方法,并初步探讨了在光度分析和非有机溶剂萃取分离方面的应用。结果表明,小分子显色剂高分子化后,其分析性能有了明显改善,特别是显色灵敏度和萃取率均有不同程度的提高。     

Cryogenic Designing of Biocompatible Blends of Polyvinyl alcohol and Starch with Macroporous Architecture

The present paper discusses synthesis, characterization, and blood compatibility studies of macroporous cryogels of PVA and starch. Biocompatible spongy porous hydrogels of polyvinyl alcohol–starch have been synthesized by repeated freezing–thawing methods and characterized by Infra red (FTIR) and environmental scanning electron microscopy (ESEM) techniques, respectively, to gain insights for structural and morphological features. The FTIR analysis of prepared cryogels indicated that starch was introduced into the network of cryogel possibly via formation of hydrogen bonds between the PVA and starch clusters. The “cryogels” were evaluated for their water uptake potentials and influence of various factors such as chemical architecture of the spongy hydrogels, pH and temperature of the swelling bath were investigated on the degree of water sorption by the cryogels. The hydrogels were also swollen in salt solutions and various simulated biological fluids. The biocompatibility of the prepared cryogels was judged by in vitro methods of blood–clot formation viz. percent haemolysis and protein (BSA) adsorption. The cryogels were also studied for their pores morphology and percent porosity and the effect of chemical composition on the extent of porosity was also investigated.     

Cellulose Nanocrystals (CNCs) Induced Crystallization of Polyvinyl Alcohol (PVA) Super Performing Nanocomposite Films

This study is aimed to explore the properties of cellulose nanocrystals (CNC)/polyvinyl alcohol (PVA) composite films with and without 1,2,3,4‐butane tetracarboxylic acid (BTCA), a nontoxic crosslinker. CNC and CNC‐PVA nanocomposite films are prepared using solution‐casting technique. Differential scanning calorimetry (DSC) analyses show that crosslinking increased the glass transition temperature but reduced the melting temperature and crystallinity. Furthermore, high CNC concentrations in the PVA matrix interfere with PVA crystallinity, whereas in specific ratio between CNC and PVA, two different crystalline structures are observed within the PVA matrix. Film surfaces and fracture topographies characterized using scanning electron microscope indicate that at certain CNC‐PVA ratios, micron‐sized needle‐like crystals have formed. These crystalline structures correlate with the remarkable improvement in mechanical properties of the CNC‐PVA nanocomposite films, that is, enhanced tensile strain and toughness to 570% and 202 MJ m^?3, respectively, as compared to pristine PVA. BTCA enhances the tensile strain, ultimate tensile stress, toughness, and modulus of CNC films compared to pristine CNC films. Water absorption of crosslinked CNC and CNC‐PVA nanocomposite films is significantly reduced, while film transparency is significantly improved as a function of PVA and crosslinker content. The presented results indicate that CNC‐PVA nanocomposite films may find applications in packaging, and though materials applications.     

Electrochemical Polymerization of Aniline in Polyamide and Polyvinyl Alcohol Matrices

The electrochemical polymerization of aniline was studied in polymer matrices (polyamid-12 and polyvinyl alcohol) on an electrode in the potential cycling mode from –0.2 to +0.8 V vs. SCE. The indices of this process such as the potentials and currents of the polyaniline redox peaks, polymerization rate, and properties of the conducting composite formed depend on the nature of the matrix polymer and are a function of the extent of interaction of this matrix polymer with aniline and polyaniline.     

Anomalies in the Kinetics of Swelling of the Cyclochain Copolymer of Dimethyldiallylammonium Chloride and Acrylamide in Water

Russian Journal of General Chemistry - Swelling of the cyclochain copolymer of N,N-dimethyl-N,N-diallylammonium chloride with acrylamide in water was studied. Examination of the kinetics of this...     

Oxidation and Destruction of Polyvinyl Alcohol in the Aqueous Phase

We have studied kinetic laws of polyvinyl alcohol oxidation under the action of an ozone–oxygen mixture and hydrogen peroxide in an aqueous medium. It is shown that polymer oxidation is carried out by the radical mechanism. The scheme of oxidative transformations of polyvinyl alcohol explaining the obtained results is suggested.     

氖气在聚乙烯醇多层塑料球壳内的渗透性能

采用乳液法结合等离子体涂层制备聚苯乙烯(PS)-聚乙烯醇(PVA)-辉光放电聚合物(GDP)多层塑料空心微球。通过测量不同充气平衡时间和平衡温度下球内气体的总量研究了氖气对塑料球的气体渗透系数。研究表明,当充氖温度为60、70、80、90℃时,微球充气平衡的时间分别为70~100 h、50~90 h、30~60 h,20~40 h。室温(25℃)时氖气对塑料球的渗透系数为0.5×10~19~2.0×10~19mol/(m·s·Pa),对于直径300μm,PVA壁厚2μm的微球,充Ne后的保气半寿命约3~12 d。当外压为4 MPa,平衡温度为80℃时,球内可充氖2.6~3.2 MPa。     

3-羟基-L-酪氨酸改性聚乙烯醇的制备及其性能

以3-羟基-L-酪氨酸（L-dopa）为原料,经酯化反应将L-dopa接枝到聚乙烯醇分子链上,制得具有低温（10 ℃）水溶性的改性聚乙烯醇,其结构和性能经¹H NMR, FT-IR, DSC, TGA和DTG表征。     

聚乙烯醇修饰电极的研制及应用

本文提出用玻碳电极为基体制作聚乙烯醇(PVA)修饰电极。研究了铜在该电极上的阳极溶出伏安特性。探讨了电极修饰及其作用机理。电极可用于水中痕量铜的测定,灵敏度比未修饰玻碳电极提高一个数量级以上。     

Synthesis of Beaded Polyvinyl Alcohol by Suspension Methanolysis of Polyvinyl Acetate: Derivatization and Some Applications

A new procedure for the synthesis of porous and nonporous polyvinyl alcohol beads by controlled methanolysis of different concentrations of polyvinyl acetate suspension is described. By crosslinking with epichlorohydrin, insoluble crosslinked polyvinyl alcohol gels were obtained. These gels exhibit some peculiar swelling properties related to the reticulation degree, probably due to the interchain hydrogen associations. Crosslinked polyvinyl alcohol beads can be used as supports for liquid chromatography and for enzyme immobilization. Some new stationary phases for affinity chromatography and for ion-exchange chromatography were obtained. No substantial modifications in the catalytic properties of enzyme immobilized on crosslinked polyvinyl alcohol gels were established.