改性硅橡胶富氧膜的制备

富氧膜是近年来发展起来的一种能制备富氧空气的新技术。目前国内外使用最广的富氧膜材料是甲基硅氧烷(通常称为硅橡胶)它的透氧系数Po_2=6×10~(-8)cm~3(STP)·cm/cm~2·S·cmHg,C_(O_2/N_2)=2.0,透气速度快,但机械性能较差,须予以改性,改     

硅橡胶/正硅酸乙酯杂化膜的制备及其富氧性能

硅橡胶/正硅酸乙酯杂化膜的制备及其富氧性能;气体分离;硅橡胶膜;杂化膜;富氧性能     

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。     

LTV—PSF富氧膜的复合机理研究

用不同种类和浓度的极性有机物水溶液(醇-水溶液、羧酸-水溶液、多官能团有机物-水溶液)以及四种类型(阳离子、阴离子、两性、非离子)表面活性剂水溶液处理聚砜支撑膜改变其表面化学特性,改善硅橡胶汽油溶液在其表面的铺展性能;用两次浸泡减少涂层过程中硅橡胶汽油溶液向支撑膜内的渗透程度,使LTV-PSF复合膜的透量获得较大幅度的提高。同时考察了聚砜支撑膜结构因素的影响。     

壳聚糖富氧膜的研究（Ⅱ）

壳聚糖-聚砜酰胺复合膜在干、湿情况下,其富氧性能存在明显的差别,表明壳聚糖是较好的富氧材料。从壳聚糖的结构可看出,它能通过氨基、羟基与许多重金属离子形成螯合物,这种螯合物与低分子氧载体的结构相似.本文在壳聚糖-聚砜酰胺复合膜上固定金属钴盐,并在干、湿两种状态下测定了其富氧性能的差别。     

新型液晶／高聚物复合富氧膜的富氧性能及结构表征Ⅰ．液晶／高聚物复合膜的富氧性能研究

研究用烃橡胶（ＳＢＲ、ＰＢ）和聚二甲基硅氧烷（ＰＤＭＳ）分散α，ω－对乙氧羰氧基苯甲酸聚乙二醇酯（ＰＥＥＣＢ）而得到聚合物分散液晶复合膜（ＰＤＬＣＭ）．用这种复合膜进行富氧分离，当ＰＥＥＣＢ－４．０５（４．０５为聚醚软段的数均聚合度ＤＰ）的含量超过某一临界值（约２３．０％ｗｔ）时，室温下ＳＢＲ／ＰＥＥＣＢ－４．０５／ＰＤＭＳ体系膜的氧气透过系数Ｐｏ２值达７０～６３４ｂａｒｒｅｒ），增加约６０倍，分离系数仍较高（αｏ２／Ｎ２＝３．４７～２．５９）．考察了各种影响因素对膜透气性能的影响．     

壳聚糖富氧膜的研究(Ⅰ)

壳聚糖可用来进行醇水分离,但用于氧氮分离尚未见报道.本文成功地以壳聚糖复合膜分离空气中的氧氮,并且发现干燥膜与在干燥膜表面涂上一层水的“湿膜”之间存在明显的氧氮分离差别. 1实验部分壳聚糖(浙江玉环化工厂)经水洗、酸溶、重沉淀处理后,用稀醋酸溶解,配成一定浓度的     

负载钴离子含氟硅橡胶杂化膜的制备及富氧性能

以乙丙橡胶来负载钴离子,并与含氟硅树脂一起引入到硅橡胶中,通过硅氢加成反应,在室温下制备出一种新型三元杂化膜。试验结果表明,在30℃和0.025 MPa压差条件下,三元杂化交联膜的P(O_2)和a(O_2/N_2)分别为684 Barrer和7.49,分离性能明显优于普通的含氟硅橡胶膜,富氧性能也超越了Robeson上限。与普通的含氟硅橡胶膜相比,钴离子络合物可与含氟组分之间可产生协同作用,使得对氧的促进输送作用更为显著,从而导致其氧氮分离性能进一步提高。乙丙橡胶具有良好的韧性可改善硅树脂引入而产生的变脆。     

顺丁橡胶／酯—醚液晶复合膜的富氧性能研究

首次制成顺丁橡胶（ＰＢ）与具有二重液晶相转变（近晶相，向列相）的液晶化合物双４－（４′－乙氧基苯甲酰氧基）苯甲酸－缩乙二醇酯（ＤＥＢＥＢ）的复合膜并研究了其富氧性能，ＰＢ／ＤＥＢＥＢ复合膜的液晶含量１０％时，室温下具有基质聚合物ＰＢ膜大几倍的氧透过系数。透过系数与温度的关系曲线呈现“Ｎ”型特征，这些现象与液晶的二重相变行为和膜的形态结构有关。     

PSF/SPSF高分子合金膜的膜材料对膜性能的影响

介绍了PSF与SPSF共混对合金膜的成膜性能和机械性能的影响 .二者共混改善了PSF的亲水性 ,提高了PSF膜的耐污染性 ,并且合金膜获得比PSF膜高的渗透通量     

稀土元素铈对铂铜复合膜电极结构及性能的影响

通过离子束溅射技术分别制备铂铜复合膜电极及掺杂铈元素的铂铜复合膜电极,并在相同条件下对膜电极进行热处理及酸蚀处理。通过高分辨透射电镜、X射线衍射及电化学性能测试对膜电极进行结构及性能的研究。结果表明,在相同后处理条件下,铈元素的添加使铂铜复合膜电极表面出现"桥连"结构,同时促进铂铜元素的合金化程度增强,与纯Pt相比膜电极的析氢交换电流密度提升92.25%。     

脱溶剂速度对聚砜/磺化聚砜合金膜结构和性能的影响

介绍了铸膜液温度、成膜过程中的蒸发时间、环境湿度、凝胶浴温度对聚砜/磺化聚砜合金膜的渗透、分离性能的影响.随环境相对湿度、凝胶浴温度增大,合金膜的水通量增大,截留率下降;蒸发时间延长,合金膜的水通量通过一个极大值,截留率呈现下降趋势.     

Proper and adsorbed charges on the surfaces of the polysulfonic support of a composite membrane from electrokinetic phenomena

The polysulfonic microporous layer of a composite membrane is studied. The membrane is bathed by several diluted aqueous solutions of NaCl or MgCl₂ at 298 K. The equations of transport through this microporous membrane (Nernst-Planck, Navier-Stokes, Poisson, and charge and mass conservation laws) numerically solved, with the adequate limit conditions, are used to obtain the electrokinetic coefficients. From any measured electrokinetic parameter, here the streaming potential and the membrane conductance per unit area, the adsorbed surface charge density (adsorption isotherm) and the zeta potential can be obtained as functions of concentration for each solute. A heterogeneous adsorption mechanism seems to explain the experimental results, therefore the Freundlich's isotherm is used. It is corrected, in order to take into account the complex structure of the electrical double layer and to introduce the fixed or proper charge density per unit area. The proper charge of the membrane seems to be negligible in our case. While the average adsorption Gibbs' free energy and the maximum number of accessible sites are relatively small, according to the hydrophillic character assumed for the membrane. The distribution function of the adsorption Gibbs' potential is calculated and it is seen to be sharp and concentration independent.     

A novel Mn PVC membrane electrode based on a recently synthesized Schiff base

A new PVC membrane electrode for manganese(II) ion based on a recently synthesized Schiff base of 5-[(4-nitrophenylazo)-N-hexylamine]salicylaldimine is reported. The electrode exhibits a Nernstian response for Mn²⁺ ions over a wide concentration range (4.0 × 10⁻⁷ to 1.8 × 10⁻² mol L⁻¹) with a slope of 30.1 (±1.0). The limit of detection is 1.0 × 10⁻⁷ mol L⁻¹. The electrode has a fast response time (∼10 s), a satisfactory reproducibility and relatively long life time. The proposed sensor revealed good selectivities over a wide variety of other cations include hard and soft metals. This electrode could be used in a pH range of 4.5-7.5. It was used as an indicator electrode in potentiometric titration of manganese(II) ions with EDTA solution.     

A SANS determination of the influence of external conditions on the nanostructure of nafion membrane

We have studied the structure of nafion membranes by small‐angle neutron scattering in the q range of 7 10⁻³ Å⁻¹ to 0.4 Å⁻¹. External conditions were varied: counterions, electrolyte concentration, temperature, and pretreatment of membranes. The nanostructure of Nafion exhibits a sensivity that depends on the parameters considered: changing counterions and concentration leads to a reversible local reorganization of the hydrophilic cavities, whereas changing temperature and pretreament leads to a irreversible reoganization on a larger scale. The mean variation of the radius of the hydrophilic cavities versus these parameters is about 10%. The interface between hydrophobic and hydrophilic phases appears to be sharp except when the temperature exceeds 60 °C. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 548–558, 2001     

高分子合金分离膜材料及结构研究进展

膜材料液相共混制备高分子合金分离膜不但可以调节膜材料与被分离物的亲和性，也在一定程度上改变了膜的结构。本文介绍高分子材料浓相共混对膜材料的亲水性、耐污染性及其它理化性能的影响和对膜结构的调节作用，同时指出高分子材料间的相容性是影响合金膜结构的重要因素。     

Mercury(II) ion-selective polymeric membrane sensor based on a recently synthesized Schiff base

A new polyvinyl chloride (PVC) membrane electrode that is highly selective to Hg(II) ions was prepared by using bis[5-((4-nitrophenyl)azo salicylaldehyde)] (BNAS) as a suitable neutral carrier. The sensor exhibits a Nernstian response for mercury ions over a wide concentration range (5.0×10⁻²-7.0×10⁻⁷ M) with a slope of 30±1 mV per decade. It has a response time of <10 s and can be used for at least 3 months without any measurable divergence in potential. The electrode can be used in the pH range from 1.0 to 3.5. The proposed sensor shows fairly good discriminating ability towards Hg²⁺ ion in comparison with some hard and soft metals. The electrode was used in the direct determination of Hg²⁺ in aqueous solution and as an indicator electrode in potentiometric titration of mercury ions.     

聚砜/聚醚砜相容性对合金膜结构和性能的影响

通过混合焓法预测并用相差显微镜表征了PSF/PES合金体系的相容性,表明二者为相容性比较差的部分相容体系.合金膜中聚合物的组成影响PSF/PES间的相容性,进而影响合金膜的结构和性能.随合金体系相容性下降,膜的平均孔径显著增加,水通量增大而相应的截留率下降;研究表明,改变PSF/PES间的相容性是调节膜结构、提高膜性能的有效方法.     

Effects of tertiary amines and quaternary ammonium halides in polysulfone on membrane gas separation properties

Polymers containing CO₂‐philic groups are of great interest for CO₂/light gas separation membranes because the affinity toward CO₂ can effectively increase CO₂ solubility and thus permeability. In this study, polysulfones (PSUs) modified with different degrees of benzyldimethylamine (DMA), benzyltrimethylammonium fluoride (TMAF), and benzyltrimethylammonium iodide (TMAI) were synthesized using sequential post‐functionalization reactions and investigated for CO₂/N₂ and CO₂/CH₄ separation. The physical properties of these polymers were studied, including density, fractional free volume, and glass transition temperature. In contrast to the conventional wisdom that tertiary amines exhibit an affinity toward CO₂, this study convincingly shows that the DMA substituent has a minimal impact on CO₂ solubility and CO₂/light gas solubility selectivity in PSUs under dry condition. On the other hand, incorporating TMAF and TMAI in PSU significantly increases CO₂ solubility. Particularly, introducing TMAI with a molar ratio of 1.07 relative to PSU repeating units increases CO₂/CH₄ solubility from 4.4 to 5.2, CO₂/CH₄ permeability selectivity from 21 to 45, and CO₂/N₂ permeability selectivity from 24 to 33 at 35 °C, while the CO₂ permeability decreases from 5.6 to 1.7 Barrers. The effect of these functional groups in PSUs on gas diffusivity and diffusivity selectivity can be satisfactorily described by the free volume model. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018 , 56, 1239–1250