小分子在高分子膜中无限稀释扩散系数的测定

随着高分子材料研究和应用的日益广泛,小分子在高分子中迁移规律的研究显示出其重要的理论和现实意义．小分子在高分子中的扩散系数是衡量其在高分子中迁移速率的一个重要物理量,其测定方法有多种,其中反相气相色谱法具有简便、迅速的特点且能适用于无限稀的浓度范围,反相气相色谱法早期所采用的模型是VanDeemter方程’‘·”,但此模型往往受柱子条件限制,且得出的扩散系数由于包含了小分子在气相中的扩散而其值偏大．最近R0mdhane和＂anner”‘提出了新的数学模型来描述填充柱的色谱过程,并采用矩分析法处理色谱流出峰,修正了流…     

高分子Langmuir-Blodgett膜的研究进展

利用Langmuir-Blodgett(LB)膜技术能够使薄膜中聚合物分子链获得高度有序的排列与组装,并使沉积后的膜具备可控的特殊结构以及不同寻常的物理化学性质.高分子LB膜可用于制造非线性光学材料、光电子器件、传感器单元、电极修饰膜,也可作为研究催化反应、电子转移、仿生模拟的理想模型.本文评述了芳杂环类合成高分子(聚酰亚胺、聚噻吩、聚乙烯基咔唑和聚苯胺)与几种天然高分子(木质素、纤维素、壳聚糖和蛋白质)的LB膜最近的研究进展,并详细讨论了高分子LB膜的制备、结构与表征,指出了这两类高分子LB膜的研究重点,并对该两类高分子LB膜潜在的应用进行了展望.     

水分子簇在聚丙烯酰胺膜中的渗透研究

在不同蒸气活度下,通过吸附动力学实验,测定了蒸气状态的水分子簇在聚丙烯酰胺(PAM)膜中的动态吸附曲线,改进了ENSIC模型并用于计算水分子簇在膜内的扩散系数。结果显示,随着水蒸气活度的增加,膜内水分子簇尺寸增大,并在膜的微孔内产生多层吸附甚至毛细管冷凝,导致扩散系数迅速降低。     

敏感性高分子功能膜的研究进展

某些高分子凝胶膜、膜表面或微孔内接枝改性膜、液晶膜具有化学阀的功能,其膜的通透性随外界环境条件变化而改变。详细介绍了ＰＨ、温度、电场等外界环境条件变化对此三类膜的敏感性及通透性的影响,以及敏感性功能膜在物质的分析与检测,混合物的分离与纯化过程中的应用前景。     

气体在玻璃态高分子膜中的溶解-扩散行为

本文建立了纯气体-膜体系以及混合气体-膜体系的溶解和扩散行为的通用模型,经采用玻璃态及橡胶态高分子膜在不同温度及压力下得到的实验数据证明,该模型可以只用纯气体实验得到的模型参数来预测混合气体在膜中的行为,计算值与实验结果吻合良好。     

两性离子在高分子膜表面功能化改性中的研究进展

两性离子的合成工艺简单,官能团适用性强,且在水溶液中具有较强的水合能力与抑制蛋白质吸附性,因此两性离子在高分子膜表面的功能化改性中显示出很大的优势。将两性离子接枝于高分子膜表面可得到抗污染性强,血液相容性好,环境刺激响应性迅速的功能化膜。两性离子功能化改性高分子膜不仅能广泛应用于水处理和医务治疗中的人工器官材料、血浆分离等领域,在生物医药工业中的蛋白质浓缩、净化与分离等方面同样显示出巨大的应用空间。     

导电高分子膜的电化学阻抗谱研究进展

本文结合近年来导电高分子的电化学阻抗谱（EIS）的研究进展,综述了几个EIS理论模型在导电高分子膜研究中的应用和发展。     

高分子稀溶液粘度方程中Huggins系数的新解释

高分子稀溶液的粘度常用 Huggins方程 [1] 描述 ,即ηsp/ c=[η] +k H[η] 2 c ( 1 )式中的系数 k H(称为 Huggins系数或斜率常数 )通常认为是一个表征高分子在溶液中的流体力学和热力学相互作用的无量纲数值因子 ,应是一个和分子量无关的常数 .但是早在 50年代初就已发现 ,高分Fig. 1　 Variation of k H with intrinsic viscosity forpolystyrene in toluene or benzene at2 5℃The line is calculated from eq.( 9) with A=5.54andB=0 .0 535for PS in toluene.● PS in benzene;△ oligomeric PS in benzene; PS in toluene;× …     

液晶/高分子复合材料及其在反式电控调光膜中的应用研究进展

液晶材料作为信息化时代的基础材料已经在显示领域实现了广泛的商业化应用。液晶/高分子复合材料既具有液晶材料的各向异性及外场响应特性,还具有高分子易加工成本低等特点,可以加工成大面积柔性调光薄膜,因而在建筑玻璃、智能车窗中具有广阔的应用前景。此外,液晶与高分子材料之间的相互作用会对液晶小分子取向产生影响,液晶小分子也可以作为模板控制高分子网络的形成的方向,使复合材料薄膜实现一些新的功能和特性,因此激发了大量国内外学者的研究兴趣。本文将详细介绍液晶/高分子复合材料的类型、特点、在调光膜中的应用及反式电控调光膜的最新研究进展。在此框架下,将重点阐述基于液晶/高分子复合材料的反式电控调光膜的一些新的制备方法,同时介绍目前存在的挑战及需要解决的问题,最后对反式电控调光膜近期可能实现的应用进行了展望。     

双硫腙汞络合物在高分子膜内的光色互变研究

本工作研究了双硫腙汞络合物在不同高聚物薄膜中的光色互变行为。发现所用高聚物介质的极性大小对该化合物经光照变色后的回复过程有决定性的影响,实验表明:这种影响不仅存在于高聚物介质中,而且还存在于液相介质内。因此可以认为:硫汞键的断裂以及质子转移过程是该类材料能发生光色互变反应的关键性步骤。     

Sorption and diffusion of water vapor in polyimide films

Sorption and diffusion of water vapor are investigated gravimetrically for polyimide films. The activity dependence of the solubility and diffusion coefficients, S and D, respectively, is classified under four types: (1) constant S and D type, (2) dual-mode sorption and transport type, (3) dual-mode type followed by a deviation due to a plasticization effect at high vapor activity, and (4) constant S and D type followed by a deviation due to water cluster formation at high activity. For the dual-mode type, the Henry's law component is much larger than the Langmuir component except at low activity, and therefore deviation in behavior from the first type is small. S is larger for polyimides with higher content of polar groups such as carbonyl, carboxyl, and sulfonyl. D is larger for polyimides with a higher fraction of free space, with some exceptions. The polyimide from 3,3′,4,4′-biphenyltetracarboxylic dianhydride and dimethyl-3,7-diaminodibenzothiophene-5, 5-dioxide belongs to the third type and displays both large S and large D. The polyimide from 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride and 4,4′-oxydianiline belongs to the fourth type, and has the largest D but rather small S because of the hydrophobic C(CF₃)₂ groups. © 1992 John Wiley & Sons, Inc.     

Water sorption and transport in a series of polysulfones

Water sorption and transport properties for a series of polysulfones are presented and interpreted in terms of the changes in the structure of the repeat unit compared to that of bisphenol A polysulfone. The differences between the sorption and diffusion of water and of permanent gases in these materials are also discussed. Water has the ability to interact with the polymer and with itself through hydrogen bonding in a way that permanent gases cannot. The equilibrium solubility of water in the polymer, unlike permanent gases, does not have a simple dependence on free volume but correlates more strongly with the frequency of hydrogen bonding sites on the polymer. Analysis of the sorption isotherms using the method of Zimm and Lundberg suggests that water molecules cluster in these polysulfones to various extents. For each polysulfone except polyethersulfone, the water diffusion coefficient decreases with increasing activity, which also suggests water clustering. For most of these materials, the water diffusion coefficient is larger than that of bisphenol A polysulfone and is directly related to the polymer free volume. Water permeability in these materials broadly correlates with the polymer free volume, but a favorable water-polymer interaction can be an overriding factor. © 1996 John Wiley & Sons, Inc.     

引入三氟甲基侧基对对苯醚型聚酰亚胺薄膜吸水性及水蒸汽透过性的影响

合成了3种含三氟甲基的芳香二胺,进而与3,3′,4,4′-联苯四甲酸二酐(BPDA)缩聚,得到3种对苯醚型含氟聚酰亚胺薄膜,并由4,4′-二氨基二苯醚（4,4′-ODA）与BPDA缩聚得到聚酰亚胺薄膜。 对4种聚酰亚胺薄膜的水蒸汽透过率、吸水性和热学性能的测试结果表明,其中聚合物PI-1（2,2′-BTF-4,4′-BADE+BPDA;BTF：双三氟甲基;BADE：二氨基二苯醚）的水蒸汽透过率为7.70 g/（h·m2）,吸水率为0.67%,玻璃化转变温度为259.74 ℃,质量损失5%的温度为521.40 ℃,具有良好的水蒸汽透过性和低吸水性。     

Sorption and transport of water vapor in alginic acid,sodium alginate,and alginate-cobalt complex films

The sorption and the transport of water vapor in films of alginic acid (G1), sodium alginate (G1Na), and alginate-cobalt complex (G1Co) were studied at 30°C by employing the weighing method. Sorption isotherms for all films of G1, G1Na, G1Co were of type II in the Brunauer's classification. The integral absorption from, and desorption to, zero pressure were non-Fickian type for all films studied. The mean permeability coefficient P , which was determined by the cup method, increased with the increase of vapor pressure, especially in the low vapor pressure region. P for G1Na was much higher than that for G1, which mainly reflects more hygroscopic nature of G1Na than that of G1. The values of P for G1Co were lower than those for G1 at lower pressures and then approached those for G1 at higher vapor pressures. Integral diffusion coefficient D evaluated as P /S, where the solubility coefficient S was evaluated from sorption isotherms, increased rapidly with increasing water concentration and then leveled off. In the concentration region studied, the magnitude of D and its dependence on concentration for H₂O-G1Na system did not differ much from those for H₂O-G1 system. D for H₂O-G1Co system was much lower than that for H₂O-G1 system. © 1994 John Wiley & Sons, Inc.     

聚环氧氯丙烷／液晶复合富氧膜的研究

研究了聚环氧氯丙烷(PECHCH)/N(4-乙氧基苄叉)4-丁基苯胺(EBBA)复合膜对氧气和氮气的透过性和选择性。用示差扫描量热计(DSC)、解偏振光强仪(DLI和偏光显微镜考察了复合膜的形态结构。结果表明,当PECH/EBBA复合膜处于液晶的向列相转变温度时,有较高的气体透过性和选择性。发现只有复合膜中EBBA含量在30wt％以上,PECH和EBBA呈非均相混合时,才有较明显的富氧效果。当EBBA含量达50wt%时,氧氮分离系数α=3.78。     

Sorption and transport of water in nylon-6 films

Sorption and transport properties of water through films of Nylon-6 were obtained at 5, 23, and 40°C. Commercially available films were used and a Cahn electrobalance was employed for measuring the water uptake by the polymer samples. Values of the water sorption isotherms are accurately described by the Langmuir/Flory-Huggins dual-mode sorption model. At water activity values below 0.15, the volume fraction of water described by the Langmuir portion of the model was greater than the Flory-Huggins population. Solubility and diffusion coefficients of water, as well as the diffusion activation energy and enthalpy of dissolution of water for Nylon-6, were determined from the sorption experiments. Values obtained support the hypothesis of a bimodal water sorption mode, and the formation of water clusters. © 1994 John Wiley & Sons, Inc.     

Morphology,Mechanical, and Water Barrier Properties of Carboxymethyl Rice Starch Films: Sodium Hydroxide Effect

Carboxymethyl rice starch films were prepared from carboxymethyl rice starch (CMSr) treated with sodium hydroxide (NaOH) at 10–50% w/v. The objective of this research was to determine the effect of NaOH concentrations on morphology, mechanical properties, and water barrier properties of the CMSr films. The degree of substitution (DS) and morphology of native rice starch and CMSr powders were examined. Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and differential scanning calorimetry (DSC) were used to investigate the chemical structure, crystallinity, and thermal properties of the CMSr films. As the NaOH concentrations increased, the DS of CMSr powders increased, which affected the morphology of CMSr powders; a polyhedral shape of the native rice starch was deformed. In addition, the increase in NaOH concentrations of the synthesis of CMSr resulted in an increase in water solubility, elongation at break, and water vapor permeability (WVP) of CMSr films. On the other hand, the water contact angle, melting temperature, and the tensile strength of the CMSr films decreased with increasing NaOH concentrations. However, the tensile strength of the CMSr films was relatively low. Therefore, such a property needs to be improved and the application of the developed films should be investigated in the future work.     

SAP用于铁和水蒸气反应的实验设计

利用尿不湿中的SAP材料代替棉花用于铁与水蒸气的反应,不仅可以解决棉花因碳化而难以清洗的问题,同时利用SAP材料超强的吸水性可以最大程度地吸收试管口残存的冷凝水。通过数次实验发现,选择SAP材料用于该实验,可使该反应具有实验现象明显、实验装置简单、实验材料价廉易得及安全性较强的优点。     

Composite Polymer Electrolytes for Fuel Cell Applications: Filler-Induced Effect on Water Sorption and Transport Properties

Nafion- and sulfonated polysulfone (SPS)- based composite membranes were prepared by incorporation of SnO₂ nanoparticles in a wide range of loading (0 35 wt. %). The composites were investigated by differential scanning calorimetry, dynamic vapor sorption and electrochemical impedance spectroscopy to study the filler effect on water sorption, water mobility, and proton conductivity. A detrimental effect of the filler was observed on water mobility and proton conductivity of Nafion-based membranes. An increase in water mobility and proton conductivity was instead observed in SPS-based samples, particularly at low hydration degree. Analysis of the water sorption isotherms and states of water revealed that the presence of SnO₂ in SPS enhances interconnectivity of hydrophilic domains, while not affecting the Nafion microstructure. These results enable the design of suitable electrolyte materials that operate in proton exchange membrane fuel cell conditions.     

环境敏感性聚合物膜的制备及应用进展

介绍了环境敏感性聚合物膜的分类和特性 ,综述了环境敏感性聚合物膜制备方法的最新进展 ,并阐述了环境敏感性聚合物膜的应用现状以及发展方向。