Synthesis and solution properties of a new sulfobetaine/sulfur dioxide copolymer and its use in aqueous two-phase polymer systems

The zwitterionic monomer, 3-(N,N-diallylammonio)propanesulfonate, was copolymerized with sulfur dioxide in dimethyl sulfoxide using azo-bis-isobutyronitrile (AIBN) to afford the polysulfobetaine (PSB) copolymer in excellent yields. The PSB was converted into the corresponding anionic polyelectrolyte (APE) by treatment with 1 equiv. of sodium hydroxide. The solution properties of PSB and APE were investigated by potentiometric and viscometric techniques. The critical (minimum) salt concentrations (CSC) required to promote water solubility for the PSB at 23 °C have been measured. Basicity constant of the amine functionality in APE is found to be ‘apparent’ and as such follow the modified Henderson-Hasselbalch equation. The composition and phase diagram of the aqueous two-phase polymer systems of PSB (treated with 0.60 equiv. sodium hydroxide) and poly(ethyelene glycol) (PEG) in 0.1N KCl has been studied for the first time for this class of PSB copolymer.     

Synthesis and solution properties of a new pH-responsive polymer containing amino acid residues

The amine salt, N,N-diallyl-N-carboethoxymethylammonium chloride was cyclopolymerized in water using ammonium persulfate as an initiator to afford a cationic polyelectrolyte which on acidic hydrolysis of the pendant ester groups gave the corresponding cationic acid salt (CAS). The CAS was converted into an anionic polyelectrolyte (APE) and polybetaine (PB). The solution properties of the APE having two basic functionalities were investigated in detail by potentiometric and viscometric techniques. Basicity constants of the amine as well as the carboxylate groups in APE are ‘apparent’ and as such follow the modified Henderson-Hasselbalch equation; as the degree of protonation (α) of the whole macromolecule increases, the protonation of the amine nitrogens and carboxylate groups becomes increasingly more difficult and easier, respectively. While the APE, PB and CAS were found to be soluble in salt-free water, the corresponding PB and CAS of the SO₂ copolymers of the amine salt 1 were found to be insoluble in water.     

新型聚合物表面活性剂的水溶液性质研究

采用布氏粘度计测定大庆油田用的4种聚表剂的水溶液粘度及粘度稳定性,结构表明,4种聚表剂溶液的粘度随着聚表剂浓度的增加而增大;随着剪切速率的增大先快速降低,随后变化较小,且在模拟污水中,聚表剂溶液的粘度降低较快;聚表剂溶液的粘度随着时间的延长而降低,在模拟污水,聚表剂溶液的粘度相对稳定。     

Studies of the antenna effect in polymer molecules. 29. Synthesis and properties of poly[sodium styrene sulfonate-co-(4-acryolyloxyphenyl)-10,15,20-tritolylporphyrin] in aqueous solution

The novel water soluble antenna polyelectrolyte: poly[sodium styrene sulfonate-co-(4-acryolyloxyphenyl)-10,15,20-tritolylporphyrin] (PSSS-Po) was synthesised, and its photophysical and photochemical properties were studied. Solubilisation of the various molecular probes such as pyrene or perylene in aqueous solution of the PSSS-Po proved that the polymer chain adopts the compact conformation. The interior of the polymer pseudomicelle is significantly less polar than water. The effective quenching of polymeric porphyrin fluorescence by sulfopropyl viologen (SPV) can be explained considering the possibility of electron transfer from the singlet-excited state of Po to SPV. This has been supported by measuring an absorption spectrum for PSSS-Po/SPV system after selective irradiation of Po chromophores. The formation of the new absorption bands characteristic for SPV⁻ radical anion indicated that the charge separation was achieved in that system.     

Synthesis and electrochemical characterization of PEO-based polymer electrolytes with room temperature ionic liquids

New gel polymer electrolytes containing 1-butyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imide (BMPyTFSI) ionic liquid are prepared by solution casting method. Thermal and electrochemical properties have been determined for these gel polymer electrolytes. The addition of BMPyTFSI to the P(EO)₂₀LiTFSI electrolyte results in an increase of the ionic conductivity, and at high BMPyTFSI concentration (BMPy⁺/Li⁺ = 1.0), the ionic conductivity reaches the value of 6.9 × 10⁻⁴ S/cm at 40 °C. The lithium ion transference numbers obtained from polarization measurements at 40 °C were found to decrease as the amount of BMPyTFSI increased. However, the lithium ionic conductivity increased with the content of BMPyTFSI. The electrochemical stability and interfacial stability for these gel polymer electrolytes were significantly improved due to the incorporation of BMPyTFSI.     

Ionic conductivity of polymer gels deriving from alkali metal ionic liquids and negatively charged polyelectrolytes

We have prepared polymer gel electrolytes with alkali metal ionic liquids (AMILs) that inherently contain alkali metal ions. The AMIL consisted of sulfate anion, imidazolium cation, and alkali metal cation. AMILs were mixed directly with poly(3-sulfopropyl acrylate) lithium salt or poly(2-acrylamido-2-methylpropanesulfonic acid) lithium salt to form polymer gels. The ionic conductivity of these gels decreased with increasing polymer fraction, as in general ionic liquid/polymer mixed systems. At low polymer concentrations, these gels displayed excellent ionic conductivity of 10⁻⁴ to 10⁻³ S cm⁻¹ at room temperature. Gelation was found to cause little change in the diffusion coefficient of the ionic liquid, as measured by pulse-field-gradient NMR. These data strongly suggest that the lithium cation migrates in successive pathways provided by the ionic liquids.     

Role of water structure on phase separation in polyelectrolyte-polyethyleneglycol based aqueous two-phase systems

Partitioning of proteins in aqueous two-phase systems (ATPS) has emerged as one of the important downstream processing techniques in bioprocess technology. The phase separation behavior of polyelectrolyte-polyethyleneglycol (PEG) based ATPS have been studied to elucidate the mechanism controlling phase behavior. The effect of various inorganic salt additives revealed the importance of water structure as a major factor controlling phase separation in these systems. Nitrate and potassium (water structure breaking ions) elevated the binodial line while sulphate, phosphate and sodium (water structure making ions) depressed the binodial line in both polyacrylic acid-PEG as well as polyethylenimine-PEG based ATPS. The effect of increase in concentration of either of the constituent polymers in both systems (at constant salt concentration) always led to a greater propensity towards phase separation. These results point to a mechanism in which salt-assisted polymer-modified water structure interactions play a central role in phase separation in ATPS.     

Synthesis and rheological properties of an associative star polymer in aqueous solutions

Rheological properties of aqueous solutions and hydrogels formed by an amphiphilic star block copolymer, poly(acrylic acid)-block-polystyrene (PAA₅₄-b-PS₆)₄, were investigated as a function of the polymer concentration (C_p), temperature, and added salt concentration. The water-soluble polymer synthesised by atom transfer radical polymerization (ATRP) was found to form hydrogels at room temperature at polymer concentrations, C_p, over 22 g/L due to the interpolymer hydrophobic association of the PS blocks. Increasing C_p leads to stronger elastic networks at room temperature that show a gel-to-solution transition with increasing temperature. Increase of ionic strength decreases the moduli compared with the pure hydrogel but did not affect the gel-sol transition temperature significantly. Small-angle X-ray experiments showed two distinct scattering correlation peaks for samples above the gelling C_p, which indicates the aggregates formed due to hydrophobic association. Upon heating the intensity of the scattering correlation peaks was found to decrease indicating the loss of the network structure due to thermal motion.     

Semi-empirical model for polyelectrolyte intrinsic viscosity as a function of solution ionic strength and polymer molecular weight

Elements of Odijk-Skolnick-Fixman and Yamakawa-Fujii polymer solution theories have been modified to create a new model that correlates flexible coil polyion intrinsic viscosity behavior with solvent and polymer properties. A new dimensionless viscosity is derived and is successfully related to the dimensionless ratio of Debye-Hückel screening length to polyion charge spacing and the degree of polymerization. The model has been applied to intrinsic viscosity data reported in the scientific literature and to data collected in our laboratory, all using sodium chloride solutions ranging in ionic strength. Multiple molecular weight fractions of six compositionally different polyelectrolytes were used to obtain 73 intrinsic viscosity versus ionic strength data points for model analysis. Regression analysis was applied to empirically determine the relationships between the dimensionless groups. The resulting model equation was found statistically adequate in describing the entire data set.     

Enzyme-catalyzed peptide syntheses in aqueous polymer two-phase systems

Peptide synthesis in the aqueous polymer two-phase system was examined. Water soluble polymers adopted were dextran and polyethyleneglycol (PEG). By the modification of a proteolytic enzyme, trypsin, with dextran carrying a very small number of carboxyl groups, a separation of the enzyme from its peptide product, N-benzoyl-L-arginine glycinamide, which is relatively more soluble in a PEG phase could be realized. This separation drastically reduced a so-called "mass-law" effect, and increased the yield of the reaction product. The aqueous polymer two-phase system would be useful to enhance the usefulness of biocatalysts in organic syntheses. Received: 26 July 1996/Accepted: 18 September 1996     

Synthesis and properties of new thermosensitive polymer systems

The controlled thermal release of aqueous solvent mixtures from polymeric gel particles was investigated. A new type of a polymeric gel consisting of a maleic anhydride/poly(ethylene glycol) condensation product as a crosslinking macromonomer and acrylamides was synthesized by solution or inverse emulsion polymerization for the investigation. Afterward a shell of crosslinked polystyrene was coated to stabilize this new kind of “microcontainer” for the application. This concept was shown as generally useful for various mixtures of organic solvents and water. The cloud point temperature of the polymer gel strongly depended on the following parameters: the type and content of organic cosolvent, the degree of polymerization and constituents of the polyester moiety, and the type and content of the comonomers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

Synthesis and electrochemical properties of lithium methacrylate-based self-doped gel polymer electrolytes

In this study, a strategy for synthesizing lithium methacrylate (LiMA)-based self-doped gel polymer electrolytes was described and the electrochemical properties were investigated by impedance spectroscopy and linear sweep voltammetry. LiMA was found to dissolve in ethylene carbonate (EC)/diethyl carbonate (DEC) (3/7, v/v) solvent after complexing with boron trifluoride (BF₃). This was achieved by lowering the ionic interactions between the methacrylic anion and lithium cation. As a result, gel polymer electrolytes consisting of BF₃-LiMA complexes and poly(ethylene glycol) diacrylate were successfully synthesized by radical polymerization in an EC/DEC liquid electrolyte. The FT-IR and AC impedance measurements revealed that the incorporation of BF₃ into the gel polymer electrolytes increases the solubility of LiMA and the ionic conductivity by enhancing the ion disassociations. Despite the self-doped nature of the LiMA salt, an ionic conductivity value of 3.0 × 10⁻⁵ S cm⁻¹ was achieved at 25 °C in the gel polymer electrolyte with 49 wt% of polymer content. Furthermore, linear sweep voltammetry measurements showed that the electrochemical stability of the gel polymer electrolyte was around 5.0 V at 25 °C.     

Partitioning of anionic/nonionic polysaccharides in a segregative system of anionic polyelectrolyte mixtures in aqueous solution: Effects of polymer charge density and ionic strength of solution

The partitioning of three polysaccharides, Dextran sulfate (DxS), λ‐Carrageenan (CAR), and Dextran (Dx), and its dependence on polymer charge density and ionic strength have been investigated in the segregative mixture of poly(sodium styrene sulfonate) (NaPSS) and sodium polyacrylate‐acrylamide copolymers, NaP(AA/AM), of variable charge density, in aqueous solutions. It is shown that the solubility of all the three may be zero or finite in one or both phases, but the preferred phase is determined by the charge density on the copolymer. When charge densities are equal on the phase forming polymers, the saccharides CAR and Dx favor the phase rich in PSS, but they have greater affinity for the polymer of lower charge density when the charge densities on phase polymers are unequal. The partitioning behavior of DxS is the opposite of the other two polysachharides with respect to which phase it has the greatest affinity for. The values of the partitioning coefficients show that the system may be potentially useful for the purification of polysaccharides and other macromolecules, if appropriate conditions are selected. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1728–1734, 2006     

Complicated phase behavior and ionic conductivities of PVP-co-PMMA-based polymer electrolytes

We have used DSC, FTIR spectroscopy, and ac impedance techniques to investigate the interactions that occur within complexes of poly(vinylpyrrolidone-co-methyl methacrylate) (PVP-co-PMMA) and lithium perchlorate (LiClO₄) as well as these systems' phase behavior and ionic conductivities. The presence of MMA moieties in the PVP-co-PMMA random copolymer has an inert diluent effect that reduces the degree of self-association of the PVP molecules and causes a negative deviation in the glass transition temperature (T_g). In the binary LiClO₄/PVP blends, the presence of a small amount of LiClO₄ reduces the strong dipole-dipole interactions within PVP and leads to a lower T_g. Further addition of LiClO₄ increases T_g as a result of ion-dipole interactions between LiClO₄ and PVP. In LiClO₄/PVP-co-PMMA blend systems, for which the three individual systems—the PVP-co-PMMA copolymer and the LiClO₄/PVP and LiClO₄/PMMA blends—are miscible at all compositional ratios, a phase-separated loop exists at certain compositions due to a complicated series of interactions among the LiClO₄, PVP and PMMA units. The PMMA-rich component in the PVP-co-PMMA copolymer tends to be excluded, and this phenomenon results in phase separation. At a LiClO₄ content of 20 wt% salt, the maximum ionic conductivity occurred for a LiClO₄/VP57 blend (i.e., 57 mol% VP units in the PVP-co-PMMA copolymer).     

聚合物－聚合物双水相系统相平衡计算

利用Ｃａｂｅｘｚａｓ模型，对１４个不同平均分子量的聚乙二醇－葡聚糖－水双水相系统相平衡作了计算。与文献值比较，结果尚可。引入相互作用参数后，得到了修正的Ｃａｂｅｚａｓ模型，用此模型关联上述各双水相系统相平衡，精度有显著提高。     

聚合物－聚合物双水相系统相平衡计算

利用Ｃａｂｅｘｚａｓ模型，对１４个不同平均分子量的聚乙二醇－葡聚糖－水双水相系统相平衡作了计算。与文献值比较，结果尚可。引入相互作用参数后，得到了修正的Ｃａｂｅｚａｓ模型，用此模型关联上述各双水相系统相平衡，精度有显著提高。     

Synthesis and properties of a new crosslinkable polymer containing benzoxazine moiety in the main chain

Using difunctional phenolic and amine compounds, a new polymer with benzoxazine groups in the main chain has been synthesized through the Mannich reaction of a phenol, formaldehyde, and an amine. ¹H and ¹³C nuclear magnetic resonance spectroscopies, Fourier transform infrared spectroscopy, size exclusion chromatography, and elemental analysis are used to characterize the resulting polymer. Polymer with molecular weight of approximately 10,000 Da is obtained. The resultant polymer has a moderately broad polydispersity index. The thermal properties of the polymer have also been studied by differential scanning calorimetry and thermogravimetric analysis.     

木瓜蛋白酶在离子液体双水相中的分配行为

采用离子液体双水相提取木瓜蛋白酶。首先考察不同浓度、pH、温度的离子液体对木瓜蛋白酶活性的影响, 其次考察不同离子液体双水相体系、离子液体侧烷基链长度及浓度、酶添加量、pH、温度对木瓜蛋白酶分配行为的影响。结果表明:[C₄mim]Cl和[C₄mim]Br体系萃取木瓜蛋白酶的效果比[C₄mim]BF₄体系好;高温(≥60℃)对离子液体双水相体系萃取木瓜蛋白酶不利。离子液体双水相萃取木瓜蛋白酶的最佳工艺条件:0.25 g·ml^-1的[C₄mim]Cl, 0.35 g·ml^-1的K₂HPO₄, pH 8.0, 酶添加量2.0 mg·ml^-1, 30℃。此条件下木瓜蛋白酶的酶活性回收率达到95.16%, 纯化因子达到1.5。为今后进一步研究该体系的放大实验或规模化生产奠定了基础。     

离子液体双水相中铕离子与牛血清白蛋白作用的研究

运用荧光光谱,研究了在离子液体双水相中铕离子(Eu3+)与牛血清白蛋白(BSA)的相互作用.研究发现铕离子对牛血清白蛋白有较强的荧光猝灭作用,且为静态猝灭类型.根据双对数方程处理荧光猝灭数据得到了铕离子与牛血清白蛋白在不同温度下的结合常数Ka和结合位点数n.通过热力学方程求得了铕离子与牛血清白蛋白作用的热力学参数,表明...