Antibacterial behaviour of quaternized poly(vinyl chloride)-g-poly(4-vinyl pyridine) graft copolymers

Amphiphilic graft copolymers consisting of poly(vinyl chloride)(PVC) main chains and poly(4-vinyl pyridine)(P4VP) side chains were synthesized via atom transfer radical polymerization(ATRP) using direct initiation of chlorine atoms. The successful synthesis of PVC-g-P4 VP graft copolymers was confirmed by Fourier transform infrared spectroscopy(FTIR) and proton nuclear magnetic resonance(1H-NMR). Transmission electron microscope(TEM) and small angle X-ray scattering(SAXS) analysis showed that PVC-g-P4 VP exhibited microphase-separated, ordered structure with 37.6 nm of domain spacing, which was not observed in neat PVC. For antibacterial applications, the tertiary nitrogen atoms of PVC-gP4 VP was quaternized using 1-bromohexane, as confirmed by FTIR measurements. Bacteria including Escherichia coli(E. coli), Staphylococcus aureus(S. aureus), Bacillus cereus(B. cereus), and Pseudomonas aeruginosa(P. aeruginosa) were completely killed in 24 h on the quaternized PVC-g-P4VP(46% grafting) surface, indicating its excellent antibacterial behavior while it showed to be cytotoxic to mammalian cell.     

Ion-specific swelling behaviors of partially quaternized poly(4-vinyl pyridine) gel

Swelling degrees of partially quaternized poly(4-vinyl pyridine) (p.q.P4VP) were measured as functions of the degree of quaternization (D.Q.: 5, 10, 15, 30, and 50 mol%), salt concentration (0–4 M), and salt species (KF, LiCl, NaCl, KCl, CsCl, MgCl₂, KBr, LiSCN, KSCN, Na₂SO₄, and MgSO₄) to study ion effects on the three kinds of interactions involved with p.q.P4VP in aqueous systems, i.e., electrostatic interaction, hydrogen bonding to the nitrogen of the pyridine ring, and hydrophobic interaction, as well as to estimate the relative contributions of the respective ion effects to gel swelling. Upon addition of salts at the lowest salt concentration studied (0.01 M), p.q.P4VP gels, except for one with D.Q.=10%, significantly deswelled depending on the counterion species; the lowest swelling degree was observed for the thiocyanates and the highest one for KF. In the higher salt concentration region (≧1 M) where electrostatic interactions might well be screened, however, some salt systems (e.g., LiCl, KSCN) showed swelling with increased salt concentration, contrary to the common behavior of usual ionic gels. These ion-specific swelling behaviors were interpreted as being caused by additive ionic effects on the three kinds of interactions.     

The synthesis and properties of adducts between poly(4-vinyl pyridine) and metal alkyls

Poly(4-vinyl pyridine) is used as a polymeric ligand to react with metal alkyls, Me_nM (n = 3, M = Al, Ga or In; n = 2, M = Cd or Zn) to form adducts. The adducts are characterized by solid state ¹³C NMR, infrared spectroscopy, microanalyses and differential scanning calorimetry (DSC). All the adducts are nonpyrophoric and thermally dissociable, so they may have potential both for use in adduct purification processes or for use as safer metal alkyl sources for Metal–Organic Chemical Vapor Deposition.     

Copper iodide nanoparticles on poly(4-vinyl pyridine) as new and green catalyst for multicomponent click synthesis of 1,4-disubstituted-l,2,3-triazoles in water

Poly(4-vinyl pyridine) supported nanoparticle of copper(Ⅰ) iodide is reported as a green and recyclable catalyst for the regioselective synthesis of 1,4-disubstituted-1H-1,2,3-triazoles from benzyl halides,sodium azide and terminal alkynes in water. This catalyst can be recovered by simple filtration and recycled up to 8 consecutive runs without any loss of its efficiency.     

The Amperometric Glucose Enzyme Electrode by Immobilized Glucose Oxidase in Glucose Oxidase/N-ethyl-Poly (4-vinyl)pyridine Multilayer

Enzylnebasedampcr()metricbiosensorsha\'eattractedincreasinginterestinthe1astt`xodecades.Inordertofabricate[heenzyn1elayer,considerahlceff()rtsha\,eheendcv()tcdt(1thedeveloprnent()fvari()ustechniquesf()rin1n1obilizingthcen/yn1c"2.Rcccntly.thcp()lyelectrolyte-proteincomplcx111ultilayerassen1blybyaIternateelectr()staticadsorptionhasbcenrep()rted',amullilaycrc()nsistingofalterl1atepolyethylenimineandglucoseoxidasclaycrswasassemb1edhyLv()veltl/>.ThesebioIllo1eculararthitecturesopenawaytoconstruct…     

The effects of some transition-metal compounds on the flame retardance of poly(styrene-co-4-vinyl pyridine) and poly(methyl methacrylate-co-4-vinyl pyridine)

Several copolymers of both styrene and methyl methacrylate with 4-vinyl pyridine have been prepared and modified by coordination with the transition-metal compounds vanadium acetylacetonate (VO[acac]₂), vanadyl dichloride (VOCl₂) and ferric chloride. The flame-retardant effects of these modifications have been assessed by measurements of limiting oxygen indices, by thermogravimetric analysis, and by examination of chars by scanning electron microscopy. Effects on mechanical properties have been assessed by dynamic mechanical thermal analysis. The limiting oxygen indices of the modified polymers are significantly higher than those of the parent polymers, and the production of considerable amounts of rigid, intumescent chars suggests predominantly condensed-phase mechanisms of flame retardance.     

Glass transition of thin films of poly(2-vinyl pyridine) and poly(methyl methacrylate): nanocalorimetry measurements

Glass transitions were observed in thin films of poly(2-vinyl pyridine) (P2VP) and poly(methyl methacrylate) (PMMA) using a scanning nanocalorimetry technique which has both high sensitivity (10⁻⁹ J/K) and high scan rates (10⁴-10⁵ K/s). Samples were deposited by the spin-cast method. The thickness of samples was 100-400 nm. Glass transition temperature, obtained by nanocalorimetry, is shifted toward higher temperatures by 10-20 K and activation enthalpy of glass transition is shifted to lower values by factor of 2-4. The glass transition characteristics of both polymers are discussed in terms of the standard Tool-Narayanaswamy-Moynihan (TNM) multi-parameter model.     

聚环氧乙烷与聚2-乙烯基吡啶混物的导电率及高氯酸锂的增容作用

研究了聚环氧乙烷(PEO)/聚2-乙烯基吡啶(P2VP)的共混物分别经LiCLO₄、四氰基代苯醌二甲烷(TCNQ)及两者共同掺杂后其共混物的离子、电子及混合导电率。当PEO与P2VP的重量比分别为6/4、5/5及4/6时,共混物的混合导电率大于相应的离子及电子导电率的总和,呈现协同效应。从共混物外观的研究发现LiCLO₄能作为PEO/P2VP共混体系的增容剂。     

Kinetic hydrate inhibitor performance of new copolymer poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine)s with TBAB

In oil and gas field, the application of kinetic hydrate inhibitors (KHIs) independently has remained problematic in high subcooling and high water-cut situation. One feasible method to resolve this problem is the combined use of KHIs and some synergists, which would enhance KHIs’ inhibitory effect on both hydrate nucleation and hydrate crystal growth. In this study, a novel kind of KHI copolymer poly(N-vinyl-2-pyrrolidone-co-2-vinyl pyridine)s (HGs) is used in conjunction with TBAB to show its high performance on hydrate inhibition. The performance of HGs with different monomer ratios in structure II tetrahydrofuran (THF) hydrate is investigated using kinetic hydrate inhibitor evaluation apparatus by step-cooling method and isothermal cooling method. With the combined gas hydrate inhibitor at the concentration of 1.0 wt%, the induction time of 19 wt% THF solution could be prolonged to 8.5 h at a high subcooling of 6℃. Finally, the mechanism of HGs inhibiting the formation of gas hydrate is proposed.     

丙烯酸丁酯/4-乙烯基吡啶共聚物与聚氯乙烯共混相容性的研究

合成了系列丙烯酸丁酯/4-乙烯基吡啶共聚物[P(BAVP)].以四氢呋喃为溶剂,用溶剂浇铸法制备了一系列P(BAVP)与聚氯乙烯(PVC)的共混物.动态力学性能测试表明:共混物中吡啶环含量高于1%(摩尔百分含量)的共混物呈均相,即共聚物与PVC相容.P(BAVP)/PVC共混物的T_g随PVC含量和乙烯基吡啶链段含量增加而提高.由红外光谱分析推论出:P(BAVP)分子间的作用力比PBA分子间作用力弱,从而使P(BAVP)与PVC的相容性提高.     

Mechanical properties and morphology of epoxy/poly(vinyl acetate)/poly(4-vinyl phenol) brominated system

Diglycidyl ether of bisfenol-A (DGEBA)/poly(vinyl acetate) (PVAc)/poly(4-vinyl phenol) brominated (PVPhBr) ternary blends cured with 4,4’-diaminodiphenylmethane (DDM) were investigated by differential scanning calorimetry (DSC), dynamic mechanical thermal analysis (DMTA) and scanning electron microscopy (SEM). Homogeneous (DGEBA+DDM)/PVPhBr networks with a unique T _g are generated. Ternary blends (DGEBA+DDM)/PVAc/PVPhBr are initially miscible and phase separate upon curing arising two T _gs that correspond to a PVAc-rich phase and to epoxy network phase. Increasing the PVPhBr content the T _gof the PVAc phase move to higher temperatures as a consequence of the PVAc-PVPhBr interactions. Different morphologies are generated as a function of the blend composition.     

Hybridization of poly(4-vinyl pyridine)-b-polystyrene-b-poly(4-vinyl pyridine) aggregates in dioxane/water solution

Self-assembly of binary blends of two triblock copolymers of poly(4-vinyl pyridine)-b-polystyrene-b-poly(4-vinyl pyridine), i.e., P4VP₄₃-b-PS₂₆₀-b-P4VP₄₃ (P1) and P4VP₄₃-b-PS₃₆₆-b-P4VP₄₃ (P2), in dioxane/water solution was studied. These two triblock copolymers individually tend to form vesicles (P2) and cylindrical micelles (P1) in dilute solution. It was found that copolymer components in the blend, sample preparation method, and annealing time had significant effect on hybridization aggregate morphology. By increasing P1 content in the copolymer blends, fraction of looped and stretched cylinders increased, while fraction of bilayers decreased. Nearly no bilayer was observed when P1 content was above 85 wt%. On the other hand, fraction of cylinders decreased while fraction of bilayers increased with the increase of P2 content in copolymer blends. Lamellar structures were obtained, when P2 content was 60 wt% in the copolymer blends, whereas cylinders were seldom found when P2 content was above 80 wt%. These results indicate that P1 and P2 copolymer molecules cooperatively participate in the formation of cylinders and vesicles. Some exotic structures, such as lamellae with protruding cylinders (LPC), incomplete vesicles with protruding cylinders (VPC), and cylindrical bilayers, have been kinetically trapped. These structures may result from intramicellar fusion processes in cylindrical micelles. The striking structures represent a compromise between bilayer and cylindrical geometries.     

Kinetics and steric limitation of quaternization of poly(4-vinylpyridine) with mesogenic ω-(4′-methoxy-4-biphenylyloxy)alkyl bromides

The kinetics and characteristics of the quaternization of poly(4-vinylpyridine) with very large alkylating agents are studied with the main aim to demonstrate the occurrence of a limitation of the reaction due to steric effect. Kinetics are carried out in sulfolane at different temperatures with two ω-(4'-methoxy-4-biphenylyloxy)alkyl bromides. An important limitation of the reaction is demonstrated: 30% of the pyridine groups are inaccessible at 333 K, 23% at 355.5 K, and 4% at 363 K. Post-quaternization experiments with butyl bromide of already partially quaternized P4VP also demonstrate this limitation. The occurrence of global steric hindrance and hydrophobic effects affecting the conformation of the chain in solution is proposed to explain the limited accessibility of the pyridine groups. The results question the classical neighboring group model generally used to describe the slowing down of the quaternization reaction with increasing quaternization ratio. The thermal stability of the quaternized polymers and the colors of the reaction medium are also discussed. © 1992 John Wiley & Sons, Inc.     

Quantitative Quaternization of Poly(4-Vinyl Pyridine)

Quaternization of poly(4-vinyl pyridine), (P4-VP) by common alkyl halides can be performed with relatively low (up to 65–70%) conversion yields. Here we describe fully quaternization of P(4-VP) with activated halides such as chloro 2-propanone and 2-chloroacetamide in dimethylformamide (DMF) at room temperature.     

Effects of chemical modifications on the swelling behaviors of poly (4-vinyl phenol) gel

Poly (4-vinyl phenol) (P4VPh) gels were prepared by crosslinking with a hydrophilic crosslinker [ethyleneglycoldiglycidylether (EGDGE)] and a hydrophobic one [diglycidyl 1,2-cyclohexane dicarboxylate (DGCHDC)], and the former gel was further modified by CH₃I or C₂H₅I to partially convert the hydrogen of phenol OH to the corresponding alkyl groups. Swelling behaviors of P4VPh gels, thus modified, were investigated to see how the hydrophobic groups introduced to the crosslinker and the polymer substrate affect the super salt resistivity to inorganic ions and the high water content (>90%) that have been observed for the original P4VPh gel. Water content and salt resistivity were unexpectedly preserved even for the modified gels. Effects of the chemical modifications on the gel swelling were only observed in the presence of hydrophobic solutes, i.e., tetrabutyl ammonium chloride and ionic surfactants. All these results strongly suggest that hydration around the polymer substrate in the gel phase is specifically stabilized, probably because of the coexistence of the hydrophobic hydration and the π-hydrogen-bonding hydration around the phenol ring.     

Photoactive proton conductor: poly(4-vinyl pyridine) gel

We describe a hydrogen-bonded poly(4-vinyl pyridine)-based dielectric material, in which conductivity can be induced due to the presence of side-chain protonated species that form spontaneously when the polymer is dissolved in pyridine. The conductivity of the proton conductive gel can be controlled by direct irradiation at the proton-transfer center: a reversible change of conductivity was observed in response to the on/off switching of 385 nm wavelength radiation. Over most of the range of intensities used, the proton conductivity exhibited a bimolecular character. We present a model of the protonated pyridine side-chain unit in the ground and excited states (DFT level). In the ground state, the protonated pyridine moiety has a cyclic, conjugated structure.     

Mechanism of the Reaction of Picryl Iodide with 4-[4-(Dimethylamino)styryl]pyridine

We have used semiempirical calculations (PM3, MNDOd) to show that the parabolic dependence of the rate constants (k_obs, s⁻¹) on the picryl iodide (PicI) concentration in the reaction of quaternization of 4-[4-(dimethylamino)styryl]pyridine (DASP) in acetonitrile is due to formation of an inactive σ_1,3 adduct from DASP and PicI. Formation of the σ_1,1 adduct is the rate-limiting step of the S_NAr substitution. __________ Translated from Teoreticheskaya i Eksperimental'naya Khimiya, Vol. 41, No. 4, pp. 242–246, July–August, 2005.     

Novel,One-Pot,Three-Component,Regioselective Synthesis of Fluorine-Containing Thiazole and Bis-3H-thiazole Derivatives Using Polyvinyl Pyridine as Heterogeneous Catalyst,and Evaluation of Their Antibacterial Activity

A convenient, one-pot, three-component regioselective synthesis of novel 2,2′-(1,4-phenylene)-bis-(3-aryl-2-substituted imino-4-aryl-3H-thiazole) derivatives from 1,4-phenylene diisothiocyanate, aryl amines, and various phenacyl bromide, and also the regioselective synthesis of 3-alkyl-2-(aryl imino)-4-cyclopropyl-5-(2′-fluorophenyl)-thiazole derivatives from alkylisothiocyanate, aryl amines, and 2-bromo-2-(2-fluorophenyl)-1-cyclopropylethanone in the presence of poly-4-vinyl pyridine as heterogenous basic catalyst are described. This efficient method produced the products at room temperature with excellent yields (82–96%). The structures of all products were characterized by spectral and elemental analyses. The antimicrobial activity of the synthesized compounds was evaluated against Salmonella enterica, Micrococcus luteus, Bacillus subtilis, and Pseudomonas aeruginosa.     

Miscibility of poly(vinyl chloride) with ethyl acrylate 4-vinyl pyridine copolymers

Blends (50:50, w:w) of poly(vinyl chloride) (PVC) and poly(ethyl acrylate-co-4-vinyl pyridine) (PEA–4-VP) of different 4-VP contents (2–14 mol %) were prepared. These were found to be partially miscible as evidenced by the presence of a single, through broad, tangent δ peak obtained from torsion pendulum experiments. Several possible types of interactions which might exist between PVC and PEA-4-VP, such as ion-dipole, crosslinking, charge transfer, hydrogen bonding, and dipole–dipole interactions, were explored. From ultraviolet, conductance, infrared, and solubility studies, it was shown that hydrogen bonding or dipole–dipole (or possibly a combination of the two) interactions were the most likely in this system. These interactions have been suggested previously for other systems by various investigators.