Cross-linked poly(4-vinylpyridine/styrene) copolymers as a support for immobilization of ytterbium triflate

Eight cross-linked poly(4-vinylpyridine/styrene) (P/S) resins (as beads) were prepared by radical suspension polymerization. Ytterbium triflate was immobilized in the range of 0.10-0.24 mmol/g by mixing with the P/S resins. The ytterbium triflate-immobilized P/S resins exhibited good activity in two Lewis acid-catalyzed reactions. Low pyridine containing resins were recycled with no loss of activity, while a slight loss of activity was observed with the higher pyridine containing resins.     

Stereoregularity of poly(2-vinylpyridine) and poly-(4-vinylpyridine)

In order to determine the stereoregularity of poly(4-vinylpyridine), 4-vinylpyridine-β,β-d₂ was synthesized from 4-acetylpyridine. The ¹H-NMR spectra of the deuterated and nondeuterated polymers were measured and analyzed. From the ¹H-NMR spectra of poly(4-vinylpyridine-β,β-d₂), triad tacticity can be obtained, while the ¹H-NMR spectra of nondeuterated poly(4-vinylpyridine) give the fraction of isotactic triad. The ¹³C-NMR spectra of poly(4-vinylpyridine) were also observed, and the spectra of C₄ carbon of polymers were assigned by the pentad tacticities. The fraction of isotactic triad of poly(2-vinylpyridine) and poly(4-vinylpyridine) obtained under various polymerization conditions were determined. The radical polymerization and anionic polymerizations with phenylmagnesium bromide and n-butyllithium as catalysts of 4-vinylpyridine gave atactic polymers.     

Association of copolymers of methacrylic acid and 4-vinylpyridine in comparison with an intermacromolecular complex of poly(methacrylic acid) with poly(4-vinylpyridine)

Solution properties of copolymers [C(MA-Py)x] of methacrylic acid and 4-vinylpyridine and intermacromolecular complexes of poly(methacrylic acid) (PMAA) and poly(4-vinylpyridine) (PVP) in the presence or absence of a proton-accepting water-soluble polymer such as poly(ethylene glycol) (PEG) in water/methanol mixed solvent are studied by potentiometric titration, turbidity and viscosity methods. These copolymers behave like polyampholytes and their solubilities are strongly dependent with pH changes. The pH regions where they are precipitated around their isoelectric points are narrower than those of the intermacromolecular complex of PMAA with PVP. The polyampholyte can form an intermacromolecular complex with PEG in acidic solution but this complex is soluble in the medium.     

Nanosponges as products of N-alkylation of 4-vinylpyridine and poly(4-vinylpyridines) in dilute solutions

Hydrophilic ionic nanosponges with quaternary pyridinium groups are synthesized on the basis of 4-vinylpyridine and its polymer. Their synthesis relies on the use of bior polyfunctional agents alkylating pyridine in dilute solutions in a thermodynamically good solvent. Individual intramolecularly crosslinked soluble macromolecules with molecular masses from 6000 to 400000 are prepared at various degrees of dilution. 1,4-Bis(halomethyl)benzenes, p-vinylbenzyl chloride, and poly(vinylbenzyl chloride) are used as N-alkylating agents. The shapes and sizes of macromolecules are determined via the methods of diffusion, sedimentation, viscometry, dynamic light scattering, atomic force microscopy, and transmission electron microscopy.     

Self-association effects on phase behavior and thermal properties of poly(styrene-co-itaconic acid)/poly(butyl methacrylate-co-4-vinylpyridine) blends

Blends based on poly(styrene-co-itaconic acid) containing 11 or 27 mol % of itaconic acid (PSIA11, PSIA27) and poly(n-butyl methacrylate-co-4-vinylpyridine) containing 26 or 37 mol% of 4-vinylpyridine (PBM4VP26, PBM4VP37) were prepared. Their phase behavior and thermal properties were investigated by several techniques. Specific interactions that occurred between these copolymers were evidenced by FTIR from the appearance of characteristic new bands. The different T _g-composition behaviors of these systems evidenced by DSC and interpreted in terms of different types and strength of interactions that occurred within these blends, were analyzed by Kwei and “BCKV” (Brostow, Chiu, Kalogeras, Vassilikou-Dova) approaches. The positive deviation from the weight average of their constituent T _g’s, observed with the PSIA11/PBM4VP26 and PSIA11/PBM4VP37 systems, is due to the presence of strong specific interactions that occurred within this system while the practically similar S shaped curves obtained with PSIA27/PBM4VP26 and PSIA27/PBM4VP37 blends indicate that, due to self-association of carboxylic groups within PSIA27, a reduced number of efficient specific interactions occurred within these blends even though containing relatively higher amounts of interacting species. A thermogravimetric analysis confirmed improved thermal stability of these blends over the individual copolymers.     

Effect of quinone derivatives and sulfhydryl compounds on swelling of poly(4-vinylpyridine) gels in organic solvents

Interactions of sulfhydryl compounds and quinone derivatives with poly(4-vinylpyridine) gels have been studied. Adsorption of long-chain sulfhydryl compounds onto gels causes the gel to swell, whereas oxidation of the adsorbed sulfhydryl compound to disulfide by a quinone derivative results in the gel shrinking. The higher the donating ability of the sulfhydryl compound, the stronger its interaction with a quinone derivative and thus the faster the removal from the gels, as revealed by HPLC. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 795–798, 1997     

Comparison of inorganic films and poly(4-vinylpyridine) coatings as electrode modifiers for flow-injection systems

A glassy-carbon electrode modified with a ruthenium-containing inorganic film was used for the flow-injection determination of As(III). The linear working range was 5-100 muM, and the detection limit was 300 pg. The response was reproducible for periods of several days. A glassy-carbon electrode modified by adsorption of a quaternized poly(4-vinylpyridine) film impregnated with hexachloroiridate(II and III) was used for the oxidation of nitrite. The calibration graphs were non-linear and varied from day to day, and the peak widths were broad. Nitrite determination at a platinum electrode modified by adsorption of iodine gave results analogous to the As(III) study; however, an overlayer of quaternized poly(4-vinylpyridine) decreased the sensitivity.     

聚4-乙烯基吡啶/SiO~2纳米杂化材料负载茂钛催化剂的制备 及苯乙烯聚合

以聚4-乙烯基吡啶(PVP)为有机组分,正硅酸乙酯(TEOS)为无机组分,利用sol-gel方法制得PVP/SiO~2纳米杂化材料,以此为载体制备了杂化材料负载单茂钛催化剂。利用XPS和IR分析了载体与CpTiCl~3的结合方式,确认对苯乙烯聚合有两种活性中心,苯乙烯聚合结果表明在50℃左右间规度达到最大;在70℃,n(Al)/n(Ti)=1500时活性最高可达1.09×10^6gPS/(molTi·h),GPC结果表明产物分子量分布呈双峰分布。     

Thermal degradation and stability of poly(4-vinylpyridine) homopolymer and copolymers of 4-vinylpyridine with methyl acrylate

The thermal stability and degradation behaviour of poly(4-vinylpyridine) (PVP) homopolymer and copolymers of 4-vinylpyridine and methyl acrylate (VP-MA) have been investigated. The reactivity ratios in the copolymerization were determined using an NMR method. The apparent activation energies of the degradation of the homopolymers and copolymers were calculated using the Arrhenius equation.     

The Bray-Liebhafsky reaction. Influence of some polymers based on poly (4-vinylpyridine)

Behavior of the Bray-Liebhafsky oscillatory reaction in the presence of acid-base polymers with and without ferric ions is analyzed. The influence of hydrogen ions on the overall reaction is shown.     

Functionalization of crosslinked poly(4-vinylpyridine) and poly(4-vinylpyridine-co-styrene) with permanganate species: Preparation of poly(4-vinylpyridinium permanganate)s and their use as oxidizing reagents

Crosslinked poly(4-vinylpyridine) and poly(4-vinylpyridine-co-styrene) were functionalized with permanganate group to afford the corresponding poly[4-vinyl(pyridinium permanganate)] resin. These resins were found to selectively oxidize alcohols to corresponding carbonyl compounds. These insoluble functionalized polymers possess the desired characteristics of the polymeric reagents, including operational simplicity, filterability, and regenerability. The influence of solvent, duration of reaction, and molar excess of the reagent in these oxidation reactions was investigated to find out the optimum conditions for effective oxidation reactions. The reactions were found to be more facilitated in nonpolar solvents, and a large excess of the polymeric reagent did not have any significant effect on the extent of reactions. The poly[4-vinyl(pyridinium permanganate)] resin bears a contrast to KMnO₄ and other polymer-supported oxidizing agents like poly[4-vinyl(pyridinium chlorochromate)] in that it does not bring about the oxidation of the alcohol group directly attached to the ring structure.     

Radiation immobilization of poly(methyloctylsiloxane) on silica for use in HPLC: a uniform layer model.

Poly(methyloctylsiloxane) (PMOS) was sorbed into the pores of HPLC silica by a solvent evaporation procedure, then irradiated with gamma rays from a cobalt-60 source to absorbed doses in the range from 0 to 200 kGy (1Gy = 1J kg-1). Non-irradiated and irradiated samples were characterized by solvent extraction, specific surface area determination, infrared spectroscopy and reversed-phase column performance. Solvent extraction data reveal that about 40% of the PMOS is not extractable prior to irradiation and this increases to about 75% with radiation doses of 50 kGy or higher. Column performance was improved by the radiation treatment, reaching a maximum efficiency in the dose range of 80-140 kGy while the peak symmetry changed from As = 1.7 to 1.1. The improvement is attributed to the increased mass of polymer immobilized by the radiation treatment and to a more uniform distribution of the immobilized polymer in the silica pore system. A multi-layer stationary-phase model is presented in which the first layer consists of an adsorbed monolayer of PMOS and the second layer is immobilized by gamma radiation.     

Cooperative hydrogen bonds of macromolecules. 2. Two-dimensional cooperativity in the binding of poly(4-vinylpyridine) to poly(4-vinylphenol)

The hydrogen bond interaction of poly(4-vinylphenol) (PVF), ligated by a 20 mol/mol excess of pyridine-d(5) (PD) in tetrahydrofuran-d(8), with poly(4-vinylpyridine) (PVP) was studied using liquid and solid-state NMR and quantum mechanical calculations. Because of its cooperative interaction, PVP substitutes PD in its hydrogen bond with PVF, thus forming a PVF-PVP complex, which gradually precipitates from solution. On the basis of the 1H/13C NMR spin-diffusion experiments and density functional theory quantum calculations, the complex is shown to have the fairly regular structure of a polymer sheet with intermittent H-bond links between PVF and PVP chains. The cooperativity of PVP interaction with PVF was studied by measuring the dependence of the binding degree alpha of PVP on its polymerization degree (P(n), being 10, 17, 30, 36, 48, 65, and 84) at various PVP/PVF molar ratios. The value of alpha was established indirectly by measuring the fraction of liberated PD using its 2H quadrupolar relaxation and pulsed field-gradient spin-echo measurement of self-diffusion. The cooperativity is shown to be of a higher order and two-dimensional, that is, dependent on both the polymerization degree of PVP and its ratio to PVF. A mathematical model of such two-dimensional cooperativity based chiefly on a proximity effect is suggested.     

Assembly of nanotubes of poly(4-vinylpyridine) and poly(acrylic acid) through hydrogen bonding

Nanotubes of poly(4-vinylpyridine) (PVP) and poly(acrylic acid) (PAA) were fabricated by hydrogen bonding based on layer-by-layer (LbL) assembly. The uniform and flexible tubular structures were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). FTIR and X-ray photoelectron spectroscopy (XPS) measurements confirm the formation of hydrogen bonds in the assembled nanotubes. PAA can be released from the assembled PAA/PVP nanotubes in a basic aqueous solution to give the walls of the tubes a porous structure. Such assembled nanotubes can be considered as carriers for catalysts or drugs, especially in aqueous solution against capillary force.     

A new approach for the fabrication of an alternating multilayer film of poly(4-vinylpyridine) and poly(acrylic acid) based on hydrogen bonding

A new approach for the fabrication of a multilayer film assembly is explored, which is based on the alternating assembling of poly(4-vinylpyridine) and poly(acrylic acid) via hydrogen bonding. The homogeneous multilayer films were characterized by UV-Vis, X-ray diffraction and atomic force microscopy (AFM) measurements. The nature of interaction between the two polymers is identified as hydrogen bonding by IR spectroscopy.