槲皮素和不同功能单体的分子印迹识别性能研究

以槲皮素为模板分子,采用紫外光谱法分析模板分子和甲基丙烯酸、甲基丙烯酸甲酯、丙烯酰胺和4-乙烯基吡啶等4种不同功能单体分别在二甲基亚砜和乙酸乙酯中的相互作用。结果表明,槲皮素和4-乙烯基吡啶在DMSO中有较强的相互作用,配位比1∶3,结合常数9.14×10⁵。采用微波辐射加热悬浮聚合法,以4-乙烯基吡啶为功能单体,制备了槲皮素分子印迹微球,粒径约为505。采用微波辐射加热悬浮聚合法,以4-乙烯基吡啶为功能单体,制备了槲皮素分子印迹微球,粒径约为50⁹0μm,具有能够吸附目标物的疏松多孔结构。     

高分子微球的合成及其在密封剂中的应用

以亲水性4-乙烯基吡啶(4-Vp)为微球的壳层单体、苯乙烯(St)为微球的核层单体,采用一步无皂乳液聚合法制备了PS-P4V P[聚苯乙烯-聚(4-乙烯基吡啶)]微球;然后在该高分子微球表面覆盖了一层有机硅,合成了有机-无机杂化PS-P4VP-Si[有机硅包覆的聚苯乙烯-聚(4-乙烯基吡比啶)]微球;最后分别将两种微球与聚硫橡胶共混,制备相应的聚硫密封剂。研究结果表明:PS-P4VP、PS-P4VP-Si微球大小均一,两者粒径分别为290 nm和350 nm;两种微球分别作为聚硫密封剂的填料,既能提升密封剂的性能,又能降低密封剂本身的密度(比常规密封剂降低了15%～20%);同时,这两种微球填充的聚硫密封剂具有艮好的耐热性能和耐介质性能,特别是PS-P4VP-Si微球的综合性能更优异。     

槲皮素和不同功能单体的分子印迹识别性能研究

以槲皮素为模板分子,采用紫外光谱法分析模板分子和甲基丙烯酸、甲基丙烯酸甲酯、丙烯酰胺和4-乙烯基吡啶等4种不同功能单体分别在二甲基亚砜和乙酸乙酯中的相互作用。结果表明,槲皮素和4-乙烯基吡啶在DMSO中有较强的相互作用,配位比1∶3,结合常数9.14×10~5。采用微波辐射加热悬浮聚合法,以4-乙烯基吡啶为功能单体,制备了槲皮素分子印迹微球,粒径约为50~90μm,具有能够吸附目标物的疏松多孔结构。     

P2VP-b-PS-b-PI三嵌段共聚物的RAFT合成及表征

以S-十二烷基-S’-(α,α’-二甲基-α’’-乙酸)-三硫代碳酸酯(DDMAT)为链转移剂,通过可逆加成-断裂链转移自由基聚合(RAFT)方法制备了窄分布的聚2-乙烯基吡啶。再以该聚合物为大分子链转移剂,引发苯乙烯的RAFT聚合,得到聚2-乙烯基吡啶-b-聚苯乙烯(P2VP-b-PS)的两嵌段共聚物。以P2VP-b-PS为RAFT试剂,合成聚2-乙烯基吡啶-b-聚苯乙烯-b-聚异戊二烯(P2VP-b-PS-b-PI)的三嵌段共聚物。运用1H NMR、IR和凝胶渗透色谱(GPC)等技术对产物的结构和分子量及分子量分布进行表征,采用原子力显微镜(AFM)观察三嵌段共聚物薄膜的微相分离结构。结果表明,所得三嵌段共聚物P2VP72-b-PS136-b-PI300分子量分布较窄(PDI=1.69),合成过程具有活性/可控聚合特征,聚合物薄膜经溶剂退火处理后出现了明显的微观相分离结构。     

吡啶基聚离子液体的制备及热降解行为研究

聚离子液体兼备了离子液体和聚合物的优良性质和结构特点,正成为新的研究热点。本文以4-乙烯基吡啶(VP)和二乙烯基苯(DVB为单体,过二硫酸钾(KPS)为引发剂,通过乳液聚合的方法制备了吡啶基聚离子液体。采用红外光谱分析法、热重分析等表征了聚离子液体的结构以及热稳定性,同时利用Kissinger法对吡啶基聚合离子液体的热降解动力学进行了研究。     

聚4—乙烯基吡啶的制备研究

聚４－乙烯基吡啶薄膜修饰电极具有离子交换性能，聚４－乙烯基吡啶是制备该修饰电极的主要材料，本文研究了在实验室条件下制备聚４－乙烯基吡啶的方法。     

2-乙烯基吡啶-甲基丙烯酸甲酯两嵌段共聚物的合成与表征

采用阴离子活性聚合方法合成了聚2-乙烯基吡啶(P2VP)-聚甲基丙烯酸甲酯(PMMA)两嵌段共聚物(P2VP-b-PMMA),并采用GPC、FT-IR、NMR等手段进行了结构表征.结果表明,聚合产物为数均分子量103166、多分散指数1.08的单分散P2VP-b-PMMA.     

“一锅法”合成4-二甲氨基吡啶

以4-氰基吡啶、2-乙烯基吡啶和二甲胺为主要原料,一锅法合成了4-二甲氨基吡啶。得出的最佳工艺条件为:反应物配料比m(4-氰基吡啶)/m(2-乙烯基吡啶)=1.5,使用w(NaOH)=40%的水溶液回流2 h裂解中间体,反应产率达87.4%。目标化合物通过IR、1HNMR及MS确认。     

聚4-乙烯基吡啶对碲化镉量子点的表面改性

用巯基丙酸为配体合成了碲化镉(CdTe)量子点。以聚丙烯酸(PAA)为桥梁合成了聚4-乙烯基吡啶-碲化镉(P4-VP-CdTe)复合纳米粒子。通过红外光谱(IR)和透射电镜(TEM)紫外-可见吸收光谱(UV-Vis)、荧光发射光谱(PL)对其对其进行表征。结果表明,PAA能有效的促进P4-VP与CdTe的复合,这种复合结构的形成有效的改善了CdTe的稳定性及光学性质。     

聚(丙烯酸钠-4-乙烯基吡啶)的表征

为了改善生物分解性能，在聚丙烯酸钠主链上引入了少量4-乙烯基吡啶，并对共聚产物进行了IR、UV、元素分析、热稳定性、螯合性能、分散性能等研究。结果表明，共聚产物中原来的吡啶环已经质子化，形成两性离子聚合物，聚合物的热稳定性随着原料中4-乙烯基吡啶含量的增加而下降，当4-乙烯基吡啶的物质的量分数为6％左右时，共聚物的粘均分子量大约1．3万，共聚物具有较好的螯合性能和分散性能。     

Modification of the adsorptive properties of charcoal by treatments with pyridines

Studies on the use of various pyridines (e.g., pyridine, 4-vinylpyridine, 4-aminopyridine, 4-cyanopyridine, and 4-n-propylpyridine) to modify the adsorptive properties of charcoal are described. The impregnated charcoals are compared with respect to adsorption capacity for carbon tetrachloride and cyanogen chloride under dynamic conditions and relative affinity for methyl iodide under equilibrium conditions. In several cases, the effect of impregnant concentration and method of impregnation were examined in detail. As part of the overall study, it was interesting to find that adsorption of 4-vinylpyridine resulted in the formation of ethanol intractable material (presumably polymer) on the surface of the charcoal which still exhibited chemical reaction activity. It would appear that adsorption of 4-vinylpyridine results in polymerization with a molecular orientation which allows pyridine nitrogens to be available for chemical reactivity. A charcoal prepared by adsorption of poly-4-vinylpyridine showed little chemical reactivity.     

Homogeneous-like solid base catalysts based on pyridine-functionalized swelling porous polymers

Reported here is the synthesis of pyridine-functionalized porous polymers, which are designed as homogeneous-like base catalysts. These highly porous catalysts have adjustable pyridine contents, high BET surface area (312–649 m²/g), large pore volume (0.5–2.0 cm³/g) and rapid swelling property, thus they efficiently combined the advantage of both homogeneous and heterogeneous catalysts. The exposure degree of active sites in our homogeneous-like catalysts has been evaluated by Cu²⁺ adsorption, giving similar capacity with homogeneously dissolved poly-4-vinylpyridine. In the Knoevenagel condensation, these materials exhibit excellent activity and stability compared with Mg–Al hydrotalcite and magnesia as well as homogeneous base catalyst of poly-4-vinylpyridine.     

Electrochemical characterization of polymer precoated lithium electrodes

The electrochemical behaviour of lithium electrodes in contact with solutions of propylene carbonate is investigated as a function of different polymer precoating materials (poly-(2-vinylpyridine) and poly-(ethylene oxide)). Impedance and polarization measurements show that the electrochemical behaviour of the surface is influenced markedly by precoating due to a modification of the passivating layer. Such information is important for lithium electrodes in batteries with organic electrolytes.     

Manufacture of graft copolymers of polyvinyl alcohol fibres with vinyl polymers

Conclusions 1. Methods have been developed, and the conditions studied, for obtaining graft copolymers of PVA fibres with polyacrylic acid, poly-2-methyl-5-vinylpyridine and polyacrylonitrile, using for formation of macroradicals carboxyl, aldehyde, and titanium groups, introduced into the fibres when they are rendered hydrophobic.2. Certain properties of the graft copolymers thus obtained have been studied. It is shown that fibres with ionogenic graft copolymers have high exchange capacities, reaching 5.8 meq/g when poly-2-methyl-5-vinylpyridine is used.S. M. Kirov Leningrad Institute of Textile and Light Industries (LITLP). Translated from Khimicheskie Volokna, No. 5, pp. 14–16, September–October, 1969.     

Dye loading of unimolecular, amphiphilic polymeric nanocontainers

Unimolecular, amphiphilic polymeric nanocontainers based on poly(2-vinylpyridine)-b-polystyrene-polymacromonomers are dispersed in organic solvents and loaded with different hydrophilic dyes in solution. The poly-2-vinylpyridine core of the nanocontainers is responsible for the dye uptake, whereas the polystyrene corona grants the solubility and stabilization of the particles. The nanocontainers are 20-30 nm in diameter and possess an excellent ability to sequester dye molecules up to 116% (w/w) or 3.20 mmol/g.     

Comb-like poly(4-vilylpyridinium) salts with dodecylsulfate, sodium bis(2-ethylhexyl) sulfosuccinate and bromide counter ions. Small-angle X-ray scattering and dynamic light scattering study

Poly(4-vinylpyridine) derivatives alkylated with dimethylsulfate, octylbromide and dodecylbromide were synthesized. Bromide anions in the polymer salts were substituted with octylsulfate, dodecylsulfate or bis(2-ethylhexyl)sulfosuccinate (AOT) anions using ion-exchange reactions. The small-angle X-ray scattering (SAXS) studies of the structure of the comb-like polysalts demonstrated their highly-ordered structure. Loading the comb-like polycation with the surfactant anions leads to additional ordering of the polysalts structure. In the case of large AOT anions the transition from lamella to hexagonal structure is observed. Polyelectrolyte - surfactant complexes (PEC) of poly(4-vinyl-1-methylpyridinium) cation with octylsulfate and dodecylsulfate counter ions demonstrate a higher degree of order than the comb-like polymers having a similar chemical structure. The SAXS studies were complemented by dynamic light scattering study of the solutions of the polymers in chloroform. In the solution the comb-like polymers and their complexes with linear surfactants have coil conformations with the size of the coils close to that of the original poly-4-vinylpyridine. The conformations of PECs with octylsulfate and dodecylsulfate counter ions are more unfolded than those of the corresponding comb-like polymers.     

Preparation of new hydrophilic poly-vinylpyridine beads and their application to immobilization of urease

Macroporous hydrophilic poly-vinylpyridine beads were prepared by suspension copolymerization of 4- (or 2-)vinylpyridine and hydrophilic cross-linking agents, such as ethylene glycol dimethacrylate (1EG) and tetraethylene glycol dimethacrylate (4EG), and their physical properties were studied. Immobilized enzymes were obtained by adsorption of urease on vinylpyridine polymers and commercially available hydrophobic polymers. The poly-4-vinylpyridine resin crosslinked with 4EG (degree of crosslinkage, 25%) showed higher water regain, larger average pore radius, and the highest adsorption of urease. Leakage of urease from immobilized urease was scarcely observed in the buffer solution used. The hydrophilicity and hydrophobicity of support affected markedly the enzymatic reaction of the immobilized enzyme. As one of the applications of the polymer-supported urease, blood urea nitrogen in human sera was determined.     

Measurement of the interaction forces between polymer coated surfaces

Polymers adsorbed onto particulate dispersions have been used to stabilise particles for many thousands of years. The dominant factor which controls the stability is the inter-particulate force. In this paper we report measurements of the interaction force profile for polymers adsorbed onto two mica surfaces. Results are presented for the case of a homopolymer, polyethylene oxide, and a block copolymer poly-2-vinylpyridene/poly-t-butyl-styrene adsorbed onto mica in a good solvent (toluene). The force profile is repulsive in both cases. However, the range of the interaction is much greater for the case of the copolymer, due to the polymer being attached to the mica in only one position (the poly-2-vinylpyridine end).     

Study of iron(III) polymer complexes using Moessbauer spectroscopy

Metal complexes were prepared on the basis of polymer ligands with carboxylic and nitrogen-containing functionalities by complexation with iron ions in aqueous solutions of FeCl₃·6H₂O and FeSO₄·2H₂O. The degree of introduction of iron ions into the polymer matrices depended on the relative content of the functional groups in the polymers studied such as polyacrylic acid, poly-4-vinylpyridine, and poly(2-N,N-dimethylaminoethyl) methacrylate. The metal content in the polymer complexes was found to vary between 9.0 and 30.0 (for acrylic acid-based copolymers); 0.1 and 5.3 (for copolymers of 4-vinylpyridine), and 19.7 and 34.4 (for poly(2-N,N-dimethylaminoethyl) methacrylate) mg metal ions per gram of polymer carrier, respectively. An attempt was made to evaluate the structure of the Fe-containing polymeric materials by Moessbauer spectroscopy. The parameters of the Moessbauer spectra such as the isomer shift, quadrupole splitting, effective internal magnetic field, and relative weight of the partial components were consequently determined for the complexes studied at different temperatures. The results obtained proved the existence of high-spin Fe³⁺ ions in oxygen- or nitrogen-containing ligand environment.     

Synthesis of permselective membranes by radiation induced grafting of hydrophilic monomers into poly(tetrafluoroethylene) films

A large variety of permselective membranes were prepared by radiation grafting techniques. Grafting of styrene into poly-(tetrafluoroethylene) films followed by sulfonation led to strong anionic membranes showing good performance in reverse osmosis. Carboxylic membranes were prepared by grafting acrylic and methacrylic acids. Cationic membranes were obtained via grafting 4-vinylpyridine. These membranes were tested in various fractionation processes including reverse osmosis. N-vinylpyrrolidone grafts exhibited high selectivity for separating water from organic solvents by pervaporation. Bifunctional membranes containing both carboxylic and pyridine groups were obtained by two successive grafting steps either in bulk giving rise to “homogeneous” membranes with unusual swelling properties, or into localized areas generating mosaic membranes which exhibit negative osmosis and increased rates of ion-pair diffusion.