以交联聚乙烯醇为载体的离子交换剂对蛋白质的分离性能

本文对阴离子交换剂ＤＥＡ—ＰＶＴ常压液相离子交换色谱分离蛋白质的性能、分离条件进行了探讨。结果表明其对蛋白质的分离性能良好，容易洗脱。与载体交联聚乙烯醇相比，ＤＥＡ—ＰＶＴ对蛋白质的非特异性吸附明显降低。     

化学交联聚乙烯醇降失水剂的交联度与性能探究

化学交联聚乙烯醇的交联度显著影响其降失水剂的性能及应用,通过调节交联度可以使降失水剂达到所需的效果。本文选择戊二醛作为交联剂与聚乙烯醇反应,探究了反应温度、酸浓度、聚乙烯醇在共聚体系中的质量分数、戊二醛与聚乙烯醇摩尔比对聚乙烯醇交联度的影响。通过运用均匀设计方法,得出60℃、80℃、100℃的最佳交联度为1.29%、1.46%、1.29%,对应的最佳工艺条件为反应温度50℃,酸浓度0.96 mol·L~(-1),聚乙烯醇在共聚体系中的质量分数6%,戊二醛与聚乙烯醇摩尔比1.60/1.68。加有降失水剂的水泥浆的API滤失量均在50 m L以下,且流变性能良好。根据均匀设计方法得出结论,戊二醛与聚乙烯醇摩尔比对聚乙烯醇交联度的影响最大,应重点控制其数值以达到所需交联度。     

辛巴蓝FEG—A固载的交联聚乙烯醇作为亲和色谱填料

以乙酸丁酯和正庚烷作为致孔剂,乙酸乙烯酯与异氰酸三烯丙基酯进行悬浮共聚、经碱性水解得到大孔交联聚乙烯醇树脂。交联聚乙烯醇与环氧氯丙烷在碱性条件下反应,得到含有环氧基的树脂。含有环氧基的树脂与6-氨基已基-N'-辛巴蓝FEG-A反应,制得固载辛巴蓝FEG-A（一种三嗪染料）的交联聚乙烯醇树脂。将固载辛巴蓝FEG-A的交联聚乙烯醇树脂作为亲和色谱填料,对五种蛋白质（细胞色素c、溶菌酶、牛血清白蛋白、胰岛素和乳酸脱氢酶）进行了色谱分离。     

快速弱阴离子交换无孔聚合物固定相的制备及用于蛋白质的高效液相色谱分离

将粒径为3.0μm无孔单分散亲水性交联聚甲基丙烯酸环氧丙酯树脂(PGMA/EDMA)的表面经不同的化学方法改性,制备了两种不同配基的弱阴离子交换(WAX-Ⅰ和WAX-Ⅱ)色谱填料。在同等色谱条件下,比较了两种填料对蛋白质的分离性能,发现WAX-Ⅰ型填料分离性能优于WAX-Ⅱ。详细考察了WAX-Ⅰ型弱阴离子交换色谱填料流动相pH值、流速及有机溶剂等对蛋白质保留的影响。实验结果表明,当流动相流速为3mL/min时,4种标准蛋白可在2min内基线快速分离,蛋白质的保留符合阴离子交换色谱规律。该填料可以用于生物工程产品的快速分离和纯化。     

快速弱阴离子交换无孔聚合物固定相的制及用于蛋白质的高效液相色谱分离

将粒径为3.0 μm无孔单分散亲水性交联聚甲基丙烯酸环氧丙酯树脂(PGMA/EDMA)的表面经不同的化学方法改性,制备了两种不同配基的弱阴离子交换(WAX-Ⅰ和WAX-Ⅱ)色谱填料.在同等色谱条件下,比较了两种填料对蛋白质的分离性能,发现WAX-Ⅰ型填料分离性能优于WAX-Ⅱ.详细考察了WAX-Ⅰ型弱阴离子交换色谱填料流动相pH值、流速及有机溶剂等对蛋白质保留的影响.实验结果表明,当流动相流速为3mL/min时,4种标准蛋白可在2 min内基线快速分离,蛋白质的保留符合阴离子交换色谱规律.该填料可以用于生物工程产品的快速分离和纯化.     

辛巴蓝F3G-A固载的交联聚乙烯醇作为亲和色谱填料

以乙酸丁酯和正庚烷作为致孔剂,乙酸乙烯酯与异氰酸三烯丙基酯进行悬浮共聚、经碱性水解得到大孔交联聚乙烯醇树脂。交联聚乙烯醇与环氧氯丙烷在碱性条件下反应,得到含有环氧基的树脂。含有环氧基的树脂与6-氨基己基-N'-辛巴蓝F3G-A反应,制得固载辛巴蓝F3G-A (一种三嗪染料) 的交联聚乙烯醇树脂。将固载辛巴蓝F3G-A的交联聚乙烯醇树脂作为亲和色谱填料,对五种蛋白质 (细胞色素c、溶菌酶、牛血清白蛋白、胰岛素和乳酸脱氢酶) 进行了色谱分离。     

特大孔交联苯乙烯-二乙烯苯共聚物的制备和孔结构研究Ⅰ

本文以聚乙酸乙烯酯配合其它溶剂(如乙酸乙酯、正辛醇、二氧六环等)作致孔剂,制成了一系列孔径在数万埃,孔容为1ml/g(干树脂)左右的苯乙烯-二乙烯苯系特大孔交联共聚物,并进行了部分功能基反应,制成了强碱阴离子交换树脂,还讨论了一些实验结果。     

离吸附量树脂清除胆汁酸的研究

大孔吸附树脂及阴离子交换树脂对胆汁酸均有较好的清除作用。其中ＮＫ－１１０吸附树脂吸附量大，吸附速度快，经交联聚乙烯醇包膜后，该树脂不仅保持了对胆汁酸的高吸附量，而且具有良好的血液相容性。     

高吸附量树脂清除胆汁酸的研究

大孔吸附树脂及阴离子交换树脂对胆汁酸均有较好的清除作用。其中ＮＫ－１１０吸附树脂吸附量大，吸附速度快，经交联聚乙烯醇包膜后，该树脂不仅保持了对胆汁酸的高吸附量，而且具有良好的血液相容性。     

1,4-双(二苯基膦)丁烷交联的季膦化聚芳醚酮阴离子交换膜

以1,4-双(二苯基膦)丁烷为交联剂,以具有四甲基联苯结构的聚芳醚酮为基体材料,分别制备了刚性三苯基膦和柔性三丁基膦修饰的阴离子交联膜材料.交联剂在交联结构形成的过程中转变成季膦盐,在提高膜材料机械稳定性的同时保持离子交换功能基团的含量.研究了2种阴离子交换膜的尺寸稳定性、电导率、机械性能及耐碱稳定性等.研究结果表明,当交联度为20%时,三苯基膦与三丁基膦修饰的阴离子交换膜的拉伸强度分别由未交联时的27和18 MPa提高到45和30 MPa;交联的膜材料在60℃的3 mol/L KOH溶液中浸泡120 h后,三苯基膦修饰的阴离子交换膜的电导率保留率为81%,三丁基膦修饰的阴离子交换膜的电导率保留率为69%,膜的耐碱稳定性均较未交联时有明显提高.交联度相同时,三苯基膦修饰的阴离子交换膜表现出更高的拉伸强度和更好的耐碱稳定性.     

Effect of hydrophobicity of marker anions on the sensitivity of end-point detection for potentiometric titrations of anionic polyelectrolytes

A potentiometric titration method is described for the determination of anionic polyelectrolytes using a marker anion and a plasticized poly (vinyl chloride) membrane electrode sensitive to this marker anion. A solution of an anionic polyelectrolyte, such as potassium poly (vinyl sulfate) (PVSK) added the marker ion has been titrated with a solution of poly (diallyldimethylammonium chloride) (Cat-floc). The end-point has been detected as a sharp potential change due to the rapid decrease in the concentration of the marker ion caused by its association with the titrant, Cat-floc. The sharpness of the endpoint of the titration curve has been compared for several marker ions and the dodecylbenzenesulfonate ion was found to be the best among the marker anions studied.     

Interaction between dyes and polyelectrolytes. X. Excitation energy transfer in cationic dye–polyanion system

The quantum yield for the trypaflavine-photosensitized oxidation of 1-(methylthio)ethyl-3-carbamoylpyridinium chloride to 1-(methylsulfinyl)ethyl-3-carbamoylpyridinium chloride increased with increase in the concentration of methylene blue added. It was inferred that the increase in the quantum yield is due to the excitation energy transfer from trypaflavine to methylene blue. The efficiency of excitation energy transfer was enhanced on addition of potassium poly(vinyl sulfate) and was dependent on the polyanion/dye ratio. The efficiency of excitation energy transfer at the most appropriate polyanion/dye ratio was about 5 times as high than that in the absence of polyanion. The binding of dye to potassium poly(vinyl sulfate) was investigated spectrophotometrically. Correlation with the dye binding to potassium poly(vinyl sulfate) and the efficiency of excitation energy transfer between dyes was discussed.     

Effect of Halide Salts of Alkali Metals on Crystallinity of Poly(vinyl Alcohol) Cryogels

The degree of crystallinity of poly(vinyl alcohol) in cryogels obtained by single freezing at–20°С followed by thawing of 13% aqueous solutions of the polymer bearing dissolved NaCl, KCl, CsCl, KBr, and KI in the concentration of 0.7 mol/kg is determined by attenuated total reflectance Fourier transform IR spectroscopy. It is established that the addition of NaCl, KCl, and CsCl to the poly(vinyl alcohol) solution leads to a substantial increase (by 1.5–1.7 times) in the degree of crystallinity in the cryogel prepared from this solution. The effect of KCl, KBr, and KI on the degree of crystallinity strongly depends on the salt anion. The replacement of the Cl^– anion by the larger Br^– anion reduces dramatically the crystallizing effect of the salt, while the even larger I^– anion, in contrast, reduces rather than increases the degree of crystallinity relative to that of the cryogel without a salt. The effect of the salts on the crystallinity of poly(vinyl alcohol) cryogels is explained by the simultaneous action of two processes. One of them facilitates crystallization and consists in the strengthening of dehydration of poly(vinyl alcohol) owing to competition between the polymer molecules and the salt ions for the liquid water molecules during its freezing. The other process hampers crystallization and is connected with a reduction in the water freezing point under action of the salt ions.     

Chromatographic properties of zirconia-based stationary phases for ion exchange chromatography having surface bound cationic functions

A series of non-porous, microspherical zirconia-based stationary phases with surface bound cationic functions have been introduced and evaluated in ion exchange chromatography of proteins and small acidic solutes. Different surface modification procedures were evaluated in the covalent attachment of weak, strong or hybrid anion exchange moieties on the surface of non-porous zirconia micropar-ticles. N,N-Diethylaminoethanol (DEAE) was used as the weak anion exchange ligand while glycidyltrimethylammonium chloride, which was covalently attached to poly(vinyl alcohol) layer (PVAN) on the zirconia surface, constituted the strong anion exchange moiety. Partially quaternarized poly(ethyleneimine) hydroxyethylated (PEI) was used as the hybrid type of anion exchange coating. DEAE-zir-conia microparticles acted as purely cation exchange stationary phases toward basic proteins indicating the predominance of electron donor-electron acceptor interaction (EDA) with surface exposed zirconium sites as well as cation exchange mechanism via electrostatic interaction with unreacted and unshielded hydroxyl groups. PVAN-zirconia stationary phase exhibited anion exchange chromatographic properties toward acidic proteins, but EDA interaction has stayed as an important contributor to solute retention despite the presence of a relatively thick layer of poly(vinyl alcohol) on the surface of the zirconia particles. The modification of zirconia surface with partially quaternarized PEI proved to be the most effective approach to minimize Lewis acidic metallic properties of the support. In fact, PEI-zirconia stationary phase operated as an anion exchanger toward acidic proteins and other small acidic solutes.     

Highly selective GC stationary phases consisting of binary mixtures of polymeric ionic liquids

GC stationary phases composed of binary mixtures of two polymeric ionic liquids (PILs), namely, poly(1‐vinyl‐3‐hexylimidazolium) bis[(trifluoromethyl)sulfonyl]imide (poly(ViHIm‐NTf₂))/poly(1‐vinyl‐3‐hexylimidazolium) chloride (poly(ViHIm‐Cl)) and poly(1‐vinyl‐3‐hexadecylimidazolium) bis[(trifluoromethyl)sulfonyl]imide (poly(ViHDIm‐NTf₂))/poly(1‐vinyl‐3‐hexadecylimidazolium) chloride (poly(ViHDIm‐Cl)), were evaluated in terms of their on‐set bleed temperature and separation selectivity. A total of six neat or binary PIL stationary phases were characterized using the solvation parameter model to investigate the effects of the polymeric cation and anion and PIL composition on the system constants of the resulting stationary phases. The hydrogen bond basicity of the mixed poly(ViHIm‐NTf₂)/poly(ViHIm‐Cl) stationary phases was enriched linearly with the increase in the poly(ViHIm‐Cl) content. Results revealed that tuning the composition of the stationary phase allowed for fine control of the retention factors and separation selectivity for alcohols and carboxylic acids as well as selected ketones, aldehydes, and aromatic compounds. A reversal of elution order was observed for particular classes of analytes when the weight percentage of the chloride‐based PIL was increased.     

Preparation of Anion Exchange Membrane Based on Imidazolium Functionalized Poly(arylene ether ketone)

The authors presented a novel synthetic route for the imidazolium functionalized poly(arylene ether ketone)s, derived from an engineering plastics polymer, a poly(arylene ether ketone) with 3,3',5,5'-tetramethyl-4,4'-dihydroxybiphenyl moiety(PAEK-TM). The preparation of anion exchange membranes comprised converting benzylic methyl groups to bromomethyl groups by a radical reaction, followed by the functionalization of bromomethylated PAEK with alkyl imidazoles, i.e., methyl, butyl or vinyl imidazole. The structure of imidazolium functionalized PAEK was proved by ¹H NMR spectra. A class of flexible and tough membranes was then achieved by subsequent film-forming and anion exchange processes. The water uptake and hydroxide conductivities of membranes are comparable or superior to those of quaternary ammonium(QA) anion exchange membranes. This work demonstrated a new route for non-QA anion exchange membrane design, avoiding the chloromethylation reagent and precisely controlling the degree and location of imidazolium groups.     

Poly(ionic liquid)s based on imidazolium hydrogen carbonate monomer units as recyclable polymer‐supported N‐heterocyclic carbenes: Use in organocatalysis

Synthesis of novel poly(ionic liquid)s, namely, poly(1‐vinyl‐3‐alkylimidazolium hydrogen carbonate)s, denoted as poly([NHC(H)][HCO₃])s or PVRImHCO₃, where R is an alkyl group (R = ethyl, butyl, phenylethyl, dodecyl), is described. Two distinct synthetic routes were explored. The first method is based on the free‐radical polymerization (FRP) of 1‐vinyl‐3‐alkylimidazolium monomers featuring a hydrogen carbonate counter anion (HCO₃^?), denoted as VRImHCO₃. The latter monomers were readily synthesized by alkylation of 1‐vinylimidazole (VIm), followed by direct anion exchange of 1‐vinyl‐3‐alkylimidazolium bromide monomers (VRImBr), using potassium hydrogen carbonate (KHCO₃) in methanol at room temperature. Alternatively, the same anion exchange method could be applied onto FRP‐derived poly(1‐vinyl‐3‐alkylimidazolium bromide) precursors (PVRImBr). All PVRImHCO₃ salts proved air stable and could be manipulated without any particular precautions. They could serve as polymer‐supported precatalysts to generate polymer‐supported N‐heterocyclic carbenes, referred to as poly(NHC)s, formally by a loss of “H₂CO₃” (H₂O +CO₂) in solution. This was demonstrated through selected organocatalyzed reactions of molecular chemistry, known as being efficiently mediated by molecular NHC catalysts, including benzoin condensation, transesterification and cyanosilylation of aldehyde. Of particular interest, recycling of the polymer‐supported precatalysts was possible by re‐carboxylation of in situ generated poly(NHC)s. Organocatalyzed reactions could be performed with excellent yields, even after five catalytic cycles. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4530–4540     

Nanostructured modified electrodes: role of ions and solvent flux in redox active polyelectrolyte multilayer films

Electrodes modified layer-by-layer by self-assembly of redox active polyelectrolytes comprised of osmium bipyridine-pyridine derivatized poly(allyl-amine) and poly(vinyl) sulfonate have been studied by EQCM, ellipsometry, cyclic voltammetry and electrochemical impedance spectroscopy in aqueous solutions of different anions and cations. Redox driven swelling by solvent exchange during oxidation, in excess to the hydration number, occurs by perturbation of the equilibrium between the osmotic and elastic forces as a result of the electrochemical injection of charge into the film. The exchanged mass and volume change during redox switching strongly depends on the nature of the anion under anion Donnan permselectivity conditions.     

Reaction of poly(vinyl chloride) with superoxide anion

Reaction of poly(vinyl chloride) (PVC) with superoxide anion was carried out in tetrahydrofuran (THF) at 40°C in a nitrogen atmosphere. Remarkable changes in infrared (IR) spectra of the samples treated with superoxide anion were observed in the following regions: ca. 3300, 1680, 1620, and 765 cm^?1, which suggested the formation of hydroxyl groups, α,β-unsaturated ketone groups, and ethylenic structures. Ultraviolet–visible spectra also showed the formation of polyene structures. The content of chlorine in the polymer decreased and that of oxygen increased with reaction time. The reaction mechanism was discussed on the basis of these results.