聚氯乙烯-g-聚甲基丙烯酸-2-羟乙酯共聚物的合成和表征

聚氯乙烯 (ＰＶＣ)是常用医用高分子材料之一 ,可以制作储血袋、导液管、人工尿道等 .ＰＶＣ亲水性差 ,影响其生物相容性 .采用亲水性单体与ＰＶＣ接枝共聚是提高ＰＶＣ亲水性的重要方法[1] .Ｋｒｉｓｈｎａｎ等[2 ] 对Ｃｏ60 辐照下ＰＶＣ接枝Ｎ 乙烯基吡咯烷酮进行了研究 .Ｓｉｎｇｈ等[3～ 5] 采用辐照引发甲基丙烯酸在ＰＶＣ薄膜的接枝反应 ,对接枝动力学、接枝后薄膜表面形态、溶胀和抗凝血性等进行了研究 .Ｇｏｌｄｂｅｒｇ等[6] 采用辐照引发甲基丙烯酸2 羟乙酯 (ＨＥＭＡ)在ＰＶＣ薄膜上的接枝 .Ｌｅｅ等[7]采用溶液接枝共聚制备了…     

聚合物材料的吸音系数-温度-频率三元关系的研究

用驻波管技术研究了聚甲基丙烯酸乙酯（ＰＥＭＡ）和聚氯乙烯（ＰＶＣ）的吸声系数。结果表明,在玻璃化转变区域材料的吸声系数较高,ＰＥＭＡ和ＰＶＣ均具有特征吸收频率。当乍于玻璃化转变区域时,ＰＥＭＡ和ＰＶＣ的特征吸收峰的数目增加,用自由体积理论对此进行了解释。得到ＰＥＭＡ和ＰＶＣ的吸声系数－温度－频率的三维关系图。     

一种高灵敏固相测定新方法——聚氯乙烯膜光度法

对聚氯乙烯（ＰＶＣ）膜光度法的应用进行了全面综述,主要包括ＰＶＣ膜光度法的特点、ＰＶＣ膜的制作、显色机理和应用以及发展前景。     

高速搅拌对淀粉/聚乙烯醇共混物溶液成膜性能的影响

淀粉与聚乙烯醇（ＰＶＡ）溶液在高速搅拌下共混,可大大改善淀粉／ＰＶＡ共混薄膜的力学性能、透明性与耐水性,对其生物降解性有明显的影响．淀粉／ＰＶＡ共混体系在高速搅拌前后的光谱分析、显微观察、分子量及流变性能的测定表明,这些变化起因于高速搅拌增加了淀粉中直链淀粉的含量,同时提高了淀粉与ＰＶＡ共混溶液的稳定性,改善了淀粉／ＰＶＡ共混物薄膜的使用性能．     

Y2O3薄膜处理对3Cr25Ni7N合金的抗高温氧化性能的影响

采用电沉积-热解法在3Cr25Ni7N合金表面制备了Y2O3薄膜,并研究了薄膜处理对合金在1000℃空气中的抗高温氧化性能的影响。氧化动力学曲线、SEM及XRD分析结果表明,Y2O3薄膜处理使合金表面氧化膜以尖晶石结构为主,氧化膜致密,有效地抑制了Cr2O3的挥发反应,且氧化膜与基体的附着性好,因此合金在高温下的抗氧化性能得到提高,这与氧化钇薄膜在较低温度下抗高温氧化性能提高的机制是不同的。在不同温度下,Y2O3薄膜处理均可以有效提高合金的抗高温氧化性能。     

p—Si上电沉积Ni—W—P薄膜的结构与热稳定性

研究了ｐ－Ｓｉ上恒电流沉积Ｎｉ－Ｗ－Ｐ合金薄膜组成与结构的关系，讨论了镀层的组成、结构随沉积时间的变化．测定了非晶合金的晶体结构随热处理温度的改变以及ＤＴＡ曲线，结果表明，非晶Ｎｉ－Ｗ－Ｐ合金在晶化过程中形成两个纳米超微晶相，非晶Ｎｉ－Ｗ－Ｐ薄膜的热稳定性远高于通常使用的非晶Ｎｉ－Ｐ薄膜．     

同多酸和杂多酸修饰微电极的电化学研究——Ⅶ.磷钒钼杂多酸薄膜修饰…

本文详细描述了磷钒钼杂多酸（ＰＶ２Ｍｏ１０）极薄膜修饰碳纤维（ＣＦ）微电极和ＰＶ２Ｍｏ１０／聚苯胺（ＰＡｎ）薄膜修饰微电极的制备及其电化学性质。     

低能量链端对聚苯乙烯薄膜铺展和润湿行为的影响

通过低能量功能端基的表面富集作用,研究了聚苯乙烯（ＰＳ）薄膜在聚甲基丙烯酸甲酯（ＰＭＭＡ）表面上的铺展和润湿动力学．用光学显微镜跟踪了ＰＳ薄膜的润湿行为,并对高分子熔体膜中非连续部分尺寸的增大速率进行了测定．分别用ＸＰＳ和ＡＦＭ对ＰＳ薄膜的表面组成和ＰＳ液滴的平衡接触角进行了测定．发现具有低表面能的氟碳端基在薄膜表面富集使ＰＳ薄膜的表面张力下降,并使ＰＳ液滴在ＰＭＭＡ表面上的平衡接触角减小,从而使高分子熔体膜中非连续部分尺寸的增长速率下降,得到了与液液界面铺展和润湿理论一致的实验结果．     

高分子辅助倒相法制备聚乙烯醇多孔膜

采用高分子辅助倒相法制香了多孔的ＰＶＡ－ＰＶＡｃ膜,并测得其孔隙率,最大孔径,平均孔径及孔径分布。研究了影响这些孔特性的各种因素,在扫描电镜下考察了多孔膜的微观形态,制得的膜孔隙率可调节,孔径分布窄。     

锂离子电池用SnZn/Cu薄膜负极材料的研究

合金型锂离子电池负极材料由于容量高、安全性好而备受关注. 采用磁控溅射法在铜箔上渡膜制备锡锌薄膜, 经热处理后得到合金薄膜电极. 薄膜热处理后, 表面活性层形成Cu3Sn中间合金. 合金薄膜是由尺寸在5 μm左右的合金颗粒构成, 而合金颗粒则由更小的尺寸在50 nm左右微粒组成, 该合金薄膜同时具有薄膜、中间合金和纳米结构材料的特征. 合金薄膜电极具有较高的充放电容量、良好的循环性能和非常高的充放电效率. 在0.01～1.0 V (vs. Li/Li＋)区间, 电极循环200周后放电容量保持在300 mAh•g－1以上, 与第一次脱锂容量相比较, 容量保持率高达91.9%, 充放电效率大于98.0%.     

Leaching of PVP from polyacrylonitrile/PVP blending membranes: A comparative study of asymmetric and dense membranes

Poly(N‐vinyl‐2‐pyrrolidone) (PVP) has been often used as an additive to improve the structure and performances of asymmetric membrane. In this work, we examined the leaching of PVP from polyacrylonitrile/PVP asymmetric membranes regarding the effect of leaching time, PVP content, and the molecular weight of PVP. Also, comparative studies of dense membranes were performed. It was found that the water contact angle on the dense membrane surface is very low compared with that on the asymmetric membrane surface. Results from X‐ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy‐attenuated total reflection (FTIR‐ATR) showed that more amount of PVP exists at the surface layer of the dense membrane than at the asymmetric one. If the dense membrane was immersed into water for several hours and then dried in the air, the water contact angle increases and closes to that on the asymmetric membrane surface. Although leaching time was extended from 2 h to 15 days, PVP leaches out little from the asymmetric membrane. The leaching of PVP mainly occurs during the phase‐inversion process. Furthermore, the surface features were examined by atomic force microscopy and field emission scanning electron microscopy, respectively. In comparison with PVP K30, more PVP K90 remains in the asymmetric membrane based on the FTIR‐ATR spectra. However, it can be concluded from the results of XPS that at the most outer surface of the asymmetric membrane (e.g., in depth about 1～2 nm), the residual PVP K90 is almost the same with PVP K30. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 1490–1498, 2006     

聚乙烯醇缩醛膜的加湿透气性

前曾报道聚乙烯醇(PVA)与脂肪醛缩合后亲水性的羟基减少,影响到其薄膜的透湿性和透气性,本文考察PVA及其三种脂肪族缩醛物膜在加湿条件下的透气性。 PVA膜为10％PVA水溶液用流涎法制成。缩醛膜为PVA缩醛衍生     

Gas permeation through water-swollen hydrogel membranes

This work deals with water-swollen hydrogel membranes for potential CO₂ separation applications, with an emphasis on elucidating the role of water in the membrane for gas permeation. A series of hydrogel membranes with a wide range of water contents (0.9–10 g water/g polymer) were prepared from poly(vinyl alcohol), chitosan, carboxyl methyl cellulose, alginic acid and poly(vinylamine), and the permeation of CO₂, H₂, He and N₂ through the membranes at different pressures (200–800 kPa) was studied. The gas permeabilities through the dry dense membranes were measured as well to evaluate the resistance of the polymer matrix in the hydrogel membranes. It was shown that the gas permeability in water-swollen membrane is lower than the gas permeability in water, and the selectivity of the water-swollen membranes to a pair of gases is close to the ratios of their permeabilities in water. The permeability of the water-swollen membranes increases with an increase in the swelling degree of the membrane, and the membrane permeability tends to level off when the water content is sufficiently high. A resistance model was proposed to describe gas permeation through the hydrogel membranes, where the immobilized water retained in the polymer matrix was considered to form transport passageways for gas permeation through the membrane. It was shown that the permeability of hydrogel membranes was primarily determined by the water content in the membrane. The model predictions were consistent with the experimental data for various hydrogel membranes with a wide range of water contents (0.4–10 g water/g polymer).     

Formation of high-capacity protein-adsorbing membranes through simple adsorption of poly(acrylic acid)-containing films at low pH

Layer-by-layer polyelectrolyte adsorption is a simple, convenient method for introducing ion-exchange sites in porous membranes. This study demonstrates that adsorption of poly(acrylic acid) (PAA)-containing films at pH 3 rather than pH 5 increases the protein-binding capacity of such polyelectrolyte-modified membranes 3-6-fold. The low adsorption pH generates a high density of -COOH groups that function as either ion-exchange sites or points for covalent immobilization of metal-ion complexes that selectively bind tagged proteins. When functionalized with nitrilotriacetate (NTA)-Ni(2+) complexes, membranes containing PAA/polyethylenimine (PEI)/PAA films bind 93 mg of histidine(6)-tagged (His-tagged) ubiquitin per cm(3) of membrane. Additionally these membranes isolate His-tagged COP9 signalosome complex subunit 8 from cell extracts and show >90% recovery of His-tagged ubiquitin. Although modification with polyelectrolyte films occurs by simply passing polyelectrolyte solutions through the membrane for as little as 5 min, with low-pH deposition the protein binding capacities of such membranes are as high as for membranes modified with polymer brushes and 2-3-fold higher than for commercially available immobilized metal affinity chromatography (IMAC) resins. Moreover, the buffer permeabilities of polyelectrolyte-modified membranes that bind His-tagged protein are ~30% of the corresponding permeabilities of unmodified membranes, so protein capture can occur rapidly with low-pressure drops. Even at a solution linear velocity of 570 cm/h, membranes modified with PAA/PEI/PAA exhibit a lysozyme dynamic binding capacity (capacity at 10% breakthrough) of ~40 mg/cm(3). Preliminary studies suggest that these membranes are stable under depyrogenation conditions (1 M NaOH).     

Polyetherimide/polyvinylpyrrolidone vapor permeation membranes. Physical and chemical characterization

Integrally skinned capillary tube membranes were prepared by the wet-phase inversion method. A series of polyetherimide (PEI, Ultem 1000) membranes were prepared with varying amounts of polyvinylpyrrolidone (PVP) in the casting solution. The surfaces of the membranes were analyzed by electron spectroscopy for chemical analysis (ESCA). It was found that the molecular structure of PEI, both with and without PVP, changes considerably during membrane preparation. The ESCA results indicated that the amount of PEI nitrogen remaining fully imidized at the surface varied in the range 63–86%. The PVP/PEI mass ratio at the membrane surface was found to increase linearly from 0 to 0.10 as the ratio was increased from 0 to 0.43 in the casting solution. The PVP/PEI mass ratio in the membrane bulk was determined by thermogravimetric analysis (TGA) to reach a maximum of 0.067. Vapor permeation experiments were done with a water/n-propanol mixture. The addition of PVP increased the membrane selectivity (α=P_A/P_B, A=water, B=1-propanol) from 76 to 810, while the permeance for water remained relatively constant at 1.3×10⁻⁶ mol/m² s Pa.     

Effect of solution extrusion rate on morphology and performance of polyvinylidene fluoride hollow fiber membranes using polyvinyl pyrrolidone as an additive

<正>Polyvinylidene fluoride(PVDF) hollow fiber membranes prepared from spinning solutions with different polyvinyl pyrrolidone(PVP) contents(1%and 5%) at different extrusion rates were obtained by wet/dry phase process keeping all other spinning parameters constant.In spinning these PVDF hollow fibers,dimethylacetamide(DMAc) and PVP were used as a solvent and an additive,respectively.Water was used as the inner coagulant.Dimethylformamide(DMF) and water(30/70) were used as the external coagulant.The performances of membranes were characterized in terms of water flux,solute rejection for the wet membranes.The structure and morphology of PVDF hollow fiber were examined by BET adsorption,dry/wet weight method and scanning electron microscopy(SEM).It is found that the increase in PVP content and extrusion rate of spinning solution can result in the increase of water flux and decrease of solute rejection.The improvements of interconnected porous structure and pore size are induced by shear-thinning behavior of spinning solution at high extrusion rates,which could result in the increase of water flux of hollow fiber membranes.The increase of extrusion rate also leads to the increase of membrane thickness due to the recovery effect of elastic property of polymer chains.     

聚乙烯醇/聚乙烯吡咯烷酮碱性复合膜的制备及其性能

通过在不同浓度KOH溶液中进行掺杂,制备出了聚乙烯醇/聚乙烯吡咯烷酮(PVA/PVP)碱性聚合物电解质膜.详尽考察了膜的组成、微观结构、热稳定性、离子电导率和甲醇吸收率.结果表明,PVA与PVP两者具有较好的相容性,当m(PVA)∶m(PVP)=1∶0.5时,膜断面致密、均匀,未发生大尺度相分离.PVP的混入可以极大提高复合膜的电导率和热稳定性.当m(PVA)∶m(PVP)=1∶1时,复合膜的电导率可达2.01×10-3 S.cm-1.PVA/PVP/KOH膜的甲醇吸收率随温度的升高没有明显变化,100℃时其甲醇吸收率仅为同条件下Nafion 115膜的1/4.这表明该复合膜有望作为一种新型的碱性直接甲醇燃料电池用固体电解质膜且可提高膜的使用温度.     

高稳定性化学交联聚乙烯醇/聚乙烯吡咯烷酮碱性固体电解质膜

碱性固体电解质膜的稳定性是影响其在电化学领域应用的一个重要因素.本文在前期研究工作的基础上,通过直接共混和化学交联修饰制备出了聚乙烯醇/聚乙烯吡咯烷酮(PVA/PVP)碱性聚合物电解质膜.采用傅里叶变换红外(FTIR)光谱、热重分析(TGA)、扫描电镜(SEM)和交流阻抗等方法详细考察了复合膜的分子结构、热稳定性、化学稳定性、氧化稳定性和尺寸稳定性.红外光谱结果表明,PVP成功地混入聚合物基体中,在1672cm-1处表现出来自于PVP第I带C襒O的强吸收峰.TGA结果表明,提高掺杂的KOH溶液浓度对PVA/PVP碱性膜的热稳定性没有明显影响.SEM分析结果表明,复合膜经高温、高浓度碱(80℃,10mol·L-1)处理后,其断面结构仍致密均匀,未出现类似小孔等膜降解情况,此时膜电导率(1.58×10-3S·cm-1)相比室温相同碱液时提高91.5%,表明PVA/PVP膜具有很好的耐碱化学稳定性.同时,PVA/PVP碱性膜表现出良好的抗氧化性,在60℃的3%和10%H2O2溶液中处理均没有观察到明显的质量损失,150h后仍能保持原膜质量的89%和85%.此外,由于膜内形成致密的内互交联网络结构,复合膜在水中800h之后也表现出很好的同向性和电导率稳定性.     

燃料电池用聚乙烯醇基碱性聚合物电解质膜的制备及其性能

通过在不同浓度KOH溶液中进行掺杂,制备出了聚乙烯醇(PVA)、聚乙烯醇/聚乙烯吡咯烷酮(PVA/PVP)和聚乙烯醇/聚乙二醇二甲醚(PVA/PEGDE)碱性聚合物电解质膜详细考察了膜的外观形貌、微观结构、热稳定性、离子电导率和化学稳定性等.结果表明,PVA与PVP以及PEGDE具有很好的相容性,所制备的复合膜断面致密...     

Preparation and Properties of Poly(aryl ether sulfone ketone) Ultrafiltration Membrane Containing Fluorene Group for High Temperature Condensed Water Treatment

Novel poly(aryl ether sulfone ketone)s(PAESK) were synthesized from bisphenol A(BPA),9,9′-bis(4-hydroxyphenyl)fluorene(BHPF),4,4′-dichlorodiphenylsulfone(DCS) and 4,4′-difluorobenzophenone(DFB) via nucleophilic substitution polymerization,which were subsequently used to fabricate ultrafiltration membrane by phase-inversion method for high temperature condensed water treatment.The obtained high molecular weight co-polymers with fluorene group with good solubility and good thermal stability,can be easily cast into flexible,white and non-transparent flat films.The influence of molar ratio of BPA and BHPF on the properties of the prepared co-polymers and membranes was investigated in detail.SEM study of the morphology of the membranes indicated that the prepared membranes possessed homogeneous pores on the top surface and were sponge-like or finger-like in cross-section.Pure water flux of the membranes increased from 71.87 L·m~(-2)·h~(-1) to 247.65 L·m~(-2)·h~(-1),while the retention of BSA decreased slightly,and the water contact angle decreased from 82.1° to 55.6° with the PVP concentration from 0 wt% to 10 wt%.With increasing concentration of PVP,the mechanical properties of membranes decreased,while the thermal stability increased.The permeate flux measurement showed that the PAESK membrane had the potential for high temperature condensed water treatment.