Polymerization Of 4-vinylpyridine Research Articles

Poly(2-methyl-2-oxazoline) and poly(4-vinyl pyridine) based mixed brushes with switchable ability toward protein adsorption

In this work, poly[(2-methyl-2-oxazoline)-random-glycidyl methacrylate] (PMOXA-r-GMA) and poly(4-vinyl pyridine)-block-poly(glycidyl methacrylate) (P4VP-b-PGMA) were synthesized by cationic ring opening polymerization (CROP) of 2-methyl-2-oxazoline (MOXA) and reversible addition-fragmentation chain transfer (RAFT) polymerization of 4-vinyl pyridine (4VP) followed by their random and block copolymerization with glycidyl methacrylate (GMA), respectively. Then poly(2-methyl-2-oxazoline)/poly(4-vinyl pyridine) (PMOXA/P4VP) based binary polymer brushes on silicon/glass substrate were fabricated using spin coating of the mixture of PMOXA-r-GMA and P4VP-b-PGMA copolymer solution followed by annealing process at 110 °C. Afterwards, these polymer brushes were characterized via water contact angle (WCA), X-ray photoelectron spectroscopy (XPS), variable angle spectroscopic ellipsometry (VASE), and atomic force microscopy (AFM) techniques. The results showed that the surface composition on the substrate surface could be adjusted by tuning the composition of the mixture of polymer solution used for the preparation of mixed brushes. Moreover, it also showed the swelling and de-swelling of mixed polymer brushes in a systematic way between two specific points during varying the pH of the surrounding medium from 2 to 10. Finally, the tunable behavior of PMOXA/P4VP based mixed brushes against bovine serum albumin (BSA) adsorption/desorption was investigated by fluorescein isothiocyanate-labelled BSA (FITC-BSA) assay and ellipsometry measurements. The results indicated that by changing the pH value from 2 to 10, the PMOXA/P4VP based mixed brushes could adsorb and desorb protein from very low to high amount depending upon the composition of PMOXA-r-GMA and P4VP-b-PGMA in preparing solution used for the PMOXA/P4VP based coatings, and ~89% of the adsorbed protein could be desorbed under the selected conditions.

Effect of synthesis conditions on the mechanism of reversible inhibition in the TEMPO-mediated polymerization of 4-vinylpyridine

The effects of polymerization conditions (the types and concentrations of initiator and solvent, the TEMPO-to-initiator molar ratio, and temperature) on the kinetics and mechanism of pseudoliving radical polymerization of 4-vinylpyridine mediated by the nitroxide TEMPO are studied. The key quantitative parameters of the process are calculated: namely, the rate constant of reinitiation, the rate constant of inhibition, and the product of the propagation-rate constant and the pseudoliving equilibrium constant. The optimum conditions for the controlled synthesis of poly(4-vinylpyridine) mediated by TEMPO are ascertained.

The Synthesis of Polystyrene-B-Poly(4-Vinylpyridine) and its Application

a system of polystyrene and polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) were synthesized by using living free radical in the presence of 4-hydroxyl-2, 2, 6, 6-tetramethylpiperridine-oxyl-1(HTEMPO•) and (BPO). The polystyrene and diblock copolymers were characterized by gel permeation chromatography (GPC) and atomic force microscope (AFM). The results suggested that the polymerization of styrene in the presence of 4-hydroxyl-2, 2, 6, 6-tetramethylpiperridine-oxyl-1(HTEMPO•) and benzoyl peroxide (BPO) can be prepared with molecular weight distribution in the range of 1.15 to 1.25. The polystyrene with living groups can continuously initiate the living free radical polymerization of 4-Vinylpyridine to form the polystyrene-block-poly (4-vinylpyridine) with molecular weight distribution in the range of 1.08 to 1.35. The AFM of diblock indicated the diblock copolymer（PS-b-P4VP） is a good compatibilizer for PS and P4VP.

General features and specifics of the kinetics of the pseudoliving radical polymerization of 4-vinylpyridine and styrene mediated by TEMPO

The kinetics of the pseudoliving radical polymerization of 4-vinylpyridine mediated by TEMPO is studied for the first time, and quantitative parameters characterizing the pseudoliving mechanism of the reaction, namely, the rate constant of reinitiation and the product of the equilibrium constant and the propagation-rate constant, are estimated. It is shown that the general kinetic features of the TEMPO-mediated polymerizations of 4-vinylpyridine and styrene (the pattern of kinetic curves and the zero reaction order with respect to the concentration of alkoxyamine) and the distinctive features of the polymerization of 4-vinylpyridine (an abnormally low rate and a high steady-state concentration of free TEMPO) are determined by three main factors: the rate of spontaneous initiation, the rate of self-termination of macroradicals, and the constant of equilibrium between active and dormant chains.

Response to comments on the paper “Similarities and Specificity of the Kinetics of the Pseudoliving Radical Polymerization of 4-Vinylpyridine and Styrene Mediated by TEMPO”

Response to comments on the paper “Similarities and Specificity of the Kinetics of the Pseudoliving Radical Polymerization of 4-Vinylpyridine and Styrene Mediated by TEMPO”

Comments on M.Yu. Zaremski, Chen Xin, A.P. Orlova, I.V. Blagodatskikh, and V.B. Golubev’s Paper “General Features and Specifics of the Kinetics of the Pseudoliving Radical Polymerization of 4-Vinylpyridine and Styrene Mediated by TEMPO”

It is shown through a numerical experiment that, in the presence of extra (spontaneous) initiation, the equilibrium constant and the ratio between the rates of quadratic and reversible terminations cannot affect the rate of pseudoliving radical polymerization. The kinetics of the process in the steady-state region is determined only by the ratio between the rates of additional initiation and quadratic chain termination. Discrepancies between experimental data and theory must be explained with allowance for side reactions that can occur in these complex systems rather than via re-examination of the reliably verified mechanism of pseudo-living radical polymerization.

Polymerization of 4-vinylpyridine and N,N-dimethylacrylamide using a system without organic initiator

Polymerization of monomer 4-vinylpyridine (4VP) and N,N-dimethylacrylamide (DMAA) could be carried out using a system without organic initiator. It was found that metal catalyst (CuCl) and water played a vital role in this process through a series of control experiments. Polymers with high degrees of polymerization (Mp = 128739 for P4VP and Mp = 355122 for PDMAA) have been obtained by the addition of Au nanoparticles (AuNPs). Radical inhibitor and electron spin resonance (ESR) spin-trapping techniques have been used to analyze the polymerization process and identify the involvement of radicals in the reaction.

A Novel and Universal Route to SiO2-Supported Organic/Inorganic Hybrid Noble Metal Nanomaterials via Surface RAFT Polymerization

Polymer-encapsulated gold or silver nanoparticles were synthesized and sterically stabilized by a shell layer of poly(4-vinylpyridine) (P4VP) grafted on SiO(2) nanoparticles that acts as a scaffold for the synthesis of hybrid noble metal nanomaterials. The grafting P4VP shell was synthesized via surface reversible addition-fragmentation chain transfer (RAFT) polymerization of 4-vinylpyridine (4VP) using SiO(2)-supported benzyl 9H-carbazole-9-carbodithioate (SiO(2)-BCBD) as the RAFT agent. The covalently tethered P4VP shell can coordinate with various transition metal ions such as Au(3+) or Ag(+) and therefore stabilize the corresponding Au or Ag nanoparticles reduced in situ by sodium borohydride (NaBH(4)) or trisodium citrate. The SiO(2)-supported RAFT agent and the Au or Ag nanoparticles embedded in the P4VP shell layer were characterized by UV-vis spectrophotometer, X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and surface-enhanced Raman spectroscopy (SERS).

A Copper-Based Reverse ATRP Process for the Living Radical Polymerization of 4-Vinylpyridine: Discussion on Optimum Reaction Conditions

In this original experiment, reverse atom transfer radical polymerization technique using CuCl2/hexamethyl tris[2-(dimethylamino)ethyl]amine (Me6-TREN) as catalyst complex was applied to living radical polymerization of 4-vinylpyridine (4VP) with azobisisobutyronitrile (AIBN) as initiator. N,N-Dimethylformamide was used as solvent to improve the solubility of the reaction system. The polymerization not only showed the best control of molecular weight and its distribution, but also provided a rather rapid reaction rate with the molar ratio of [4VP]:[AIBN]:[CuCl2]:[Me6-TREN] = 400:1:2:2. The rate of polymerization increased with increasing the polymerization temperature and the apparent activation energy was calculated to be 51.5 kJ· mol1. Use of Cl as the halogen in copper halide had many advantages over the use of Br. The resulting poly(4-vinylpyridine) was successfully used as the macroinitiator to proceed the block polymerization of styrene in the presence of CuCl/Me6-TREN catalyst complex via a conventional ATRP process in DMF.

Selective sorption of perfluorooctane sulfonate on molecularly imprinted polymer adsorbents

Perfluorooctane sulfonate (PFOS), as a potential persistent organic pollutant, has been widely detected in water environments, and has become a great concern in recent years. PFOS is very stable and difficult to decompose using conventional techniques. Sorption may be an attractive method to remove it from water. In this study, the molecularly imprinted polymer (MIP) adsorbents were prepared through the polymerization of 4-vinylpyridine under different preparation conditions in order to remove perfluorooctane sulfonate (PFOS) from water. The MIP adsorbents using perfluorooctanoic acid (PFOA) as the template had good imprinting effects and could selectively remove PFOS from aqueous solution. The sorption behaviors including sorption kinetics, isotherms, and effect of pH, salt, and competitive anions were investigated. Experimental results showed that the sorption of PFOS on the MIP adsorbents was very fast, pH-dependent, and highly selective. The achieved fast sorption equilibrium within 1 h was attributed to the surface sorption on the fine adsorbents. The sorption isotherms showed that the sorption selectivity of PFOS on the MIP adsorbents decreased at high PFOS concentrations, which may be due to the double-layer sorption and the formation of PFOS micelles on the sorbent surface. The sorption of PFOS on the MIP adsorbents was mainly dominated by the electrostatic interaction between the protonated vinylpyridine on the adsorbent surface and the anionic PFOS. The prepared MIP adsorbents can potentially be applied in water and wastewater treatment for selective removal of PFOS.

Enhancement of Retentivity and Selectivity for PAHs in NP-HPLC by High-density Immobilization of Poly(4-vinylpyridine) as an Organic Phase on Silica

Poly(4-vinylpyridine)-modified silica with high grafting density have been prepared by a grafting-from (g-from) approach through radical chain-transfer reactions. The widely used silane coupling agent 3-mercaptopropyltrimethoxysilane was used to prepare thiol-terminated silica. Chain-transfer reaction and polymerization of 4-vinylpyridine was carried out using alpha,alpha'-azobisisobutyronitrile as an initiator. Thiol-terminated silica and polymer-modified silica were both characterized qualitatively and quantitatively. The quantification of the organic phase has been done by thermogravimetric analysis and elemental analysis. Thus, the modified silica was used as a packing material and the retention behavior of polycyclic aromatic hydrocarbons (PAHs) was studied in normal-phase high-performance liquid chromatography. Results were compared with those of poly(4-vinylpyridine)-modified silica prepared by a grafting-to (g-to) approach. Commercially available aminopropyl-bonded silica and bare silica columns were also used as reference columns. The column of poly(4-vinylpyridine)-grafted silica prepared by the g-from method, having higher grafting density, provided the better retentivity and selectivity for PAHs compared to the other reference columns.

ELECTROLESS PLATING OF COPPER ON POLYTETRAFLUOROETHYLENE FILMS MODIFIED BY SURFACE-INITIATED FREE RADICAL POLYMERIZATION OF 4-VINYLPYRIDINE

Surface modification of polytetrafluoroethylene (PTFE) films is done by exposing the films to a sodium naphthalenide ( Na /naphtha) etchant, and esterification of 4,4'-azobis(4-cyanopentanoic acid) (ACP) with the hydroxyl groups covalently linked to the surface, followed by the surface-initiated free radical polymerization of 4-vinylpyridine (4 VP). The surface elemental composition and topography of the poly(4-vinylpyridine) (PVP) graft-functionalized PTFE surfaces (PTFE-g-PVP surfaces) were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance (ATR) FTIR spectroscopy, and atomic force microscopy (AFM). Water contact angles on the pristine PTFE surface and PTFE-g-PVP surfaces were measured. The PVP brushes on the PTFE surface with well-preserved pyridine groups were used not only as the chemisorption sites for the palladium complexes (without the need for prior sensitization by SnCl 2) during the electroless plating of copper, but also as an adhesion promotion layer to enhance the adhesion of the electrolessly deposited copper to the PTFE surfaces. The T-peel adhesion strength of the electrolessly deposited copper to the PVP grafted PTFE (PTFE-g-PVP) surface could reach about 7.2 N/cm. This adhesion strength was much higher than that of the electrolessly deposited copper to the pristine or Na /naphtha-treated PTFE surface. Effects of the graft polymerization time and the activation time in the PdCl 2 solution on the T-peel adhesion strength of the electrolessly deposited copper (from the Sn -free process) to the PTFE-g-PVP surface were determined.

Fabrication of pH-Responsive Nanocomposites of Gold Nanoparticles/Poly(4-vinylpyridine)

Novel nanocomposites of gold nanoparticle and poly(4-vinylpyridine) (Au@PVP) were fabricated through surface-initiated atom-transfer radical polymerization (SI-ATRP) at ambient conditions. The citrate-stabilized gold nanoparticles were first modified by a disulfide initiator for ATRP initiation, and the following polymerization of 4-vinylpyridine (4VP) occurred on the surface of gold particles. The assembled Au@PVP nanocomposites are pH-responsive because of the pyridyl groups, which are facially protonated and positively charged. At low pH ( 3.2), the polymer chains shrink and wrap around the gold particle surface, which results in the aggregation of gold nanoparticles with a thin shrunken polymer layer under TEM observation. Such assembled A...

Polyvinyl Pyridine as a Novel Solid Heterogeneous, Recyclable Catalyst for aza-Michael Reaction

Polyvinyl pyridine (PVP) is prepared by radical polymerization of 4-vinyl pyridine. PVP was used as a heterogeneous basic catalyst for the aza-Michael reaction of secondary amines and carbamates with α,β-unsaturated esters, cyanides and ketones to obtain the corresponding adducts in excellent yields (70-90%).

The first representatives of hypercrosslinked hydrophilic networks: Alkylation and polymerization of 4-vinylpyridine in an ionic liquid

The first representatives of hypercrosslinked hydrophilic networks: Alkylation and polymerization of 4-vinylpyridine in an ionic liquid

Synthesis, Characterization, and Some Properties of 4-Vinylpyridine-Cr(CO) 5 Containing Polymers

The polymerization of 4-vinylpyridine (4VP) and 4-vinylpyridine chromium pentacarbonyl [(4VP)Cr(CO)5] was performed under N2 atmosphere at 60–80°C temperature range. Different percent of feed (%PF) of Cr(CO)5 groups were anchored into poly(4-vinylpyridine) (P4VP) by addition of the intermediate Cr(CO)5THF, which was generated photochemically from Cr(CO)6 in THF, to the polymer at ambient temperature. The determined percent of anchoring (%PA) has shown that the maximum anchored Cr(CO)5 groups was 40% (w/w) with respect to P4VP, and the optimum percent of anchoring was 20% (w/w). The rate of polymerization (R p ) and the activation energy (E a ) of 4VP in the absence and in the presence of 16.7% Cr(CO)5(4VP) were determined. Thermal analysis has shown various changes in the properties of the 4VP polymers after modification of the polymer by Cr(CO)5 groups. The X-ray diffraction and the melting enthalpy derived from the DSC thermogram revealed that the synthesized poly[(CO)5Cr(4VP)] has a crystallinity of about 40%, whereas no crystallinity was observed for pure P4VP.

Ionic conductivity of swollen LDPE/poly(4-vinylpyridine) blend

LDPE/P4VP films synthesized by in situ sorption and thermal polymerization of 4-vinylpyridine, (4VP), were used for conductivity investigations. The conductivities of swollen films varied from 7×10−6 to 1.21×10−3 S.cm−1 at room temperature depending on P4VP mass increase in the host matrix. For the temperature range of 303–333K the conductivity varied from 7×10−6 to 2.66×10−3 S.cm−1. A comparison between Arrhenius and VTF plots for conductivity measurements showed a best fit for temperature dependence according Arrhenius modified equation. The materials are stable for temperatures below 645 K.

Effects of ethyl acetate on the soap-free emulsion polymerization of 4-vinylpyridine and styrene

The properties and morphologies of poly(4-vinylpyridine-co-styrene) [P(4VP/St)] lattices, prepared by soap-free emulsion polymerization using the water-soluble initiator 2,2′-azobis(2-amidinopropane) · 2HCl (V50), were greatly affected by the addition of ethyl acetate (EA). The properties and morphologies of the resultant lattices were characterized by measuring the zeta potential, viscosity average molecular weight, particle size and distribution, glass-transition temperature (Tg), and photographs taken by SEM and TEM. The effects of two kinds of monomer feeding modes, that is, the batch and semicontinuous emulsion copolymerization, were also investigated. For batch emulsion copolymerization, by charging EA, the core–shell morphology resulting from the disparate reactivity ratios of the 4VP(1)/St(2) copolymerization system (r1= 1.04, r2= −0.73) disappeared. Instead, first a bimodal particle size distribution, with an apparently asymmetric composition structure, and then spherical microspheres were obtained as the amount of EA charged increased from 2 to 10 wt %. The particle size increased twofold by the addition of EA. The zeta potential of particles increased from +64.4 to more than +100 mV, and viscosity average molecular weight decreased from 9.70 to 0.97 × 105 g/mol, as EA increased from 0 to 8 wt %. With the semicontinuous copolymerization, raspberry-like particles were obtained by charging 10 wt % EA, whereas a sandwich-like morphology was obtained without EA. The DSC curves showed one Tg for all the lattices prepared with charging EA, but two Tg's for the latex prepared without using EA, regardless of the monomer feeding modes. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1988–2001, 2001

Synthesis and thermal properties of poly[N-(monomethoxypolyethylene oxide)-4-vinylpyridinium salt

A new type of cationic polyelectrolyte with poly(ethylene oxide) (PEO) side-chains has been prepared by the spontaneous polymerization of 4-vinylpyridine in the presence of PEO monotosylates or bromides. This very easy anionic polymerization method gives fully PEO-grafted poly(vinylpyridinium) salts of high molecular weight which are soluble in water and many organic solvents. The synthesis, characterization, and thermal properties of a series of polysalts are presented. Five monomethoxypolyethylene glycols of different molecular weights and functionalized by tosylation or bromination were used in the quaternization-polymerization of 4-vinylpyridine. These polymers present good thermal stability up to 260°C in air and decomposition takes place in two steps with the first dequaternization reaction. The effects of the PEO length and the nature of the counter-ion on the melting and glass transition temperatures have been studied. It is shown that the pyridinium structure reduces the tendency of the grafted PEO chains to crystallize. Moreover, all of these polysalts have low T g's in spite of the rigid backbone and the presence of ionic charges.

Single-ion and salt conductor polymer electrolytes based on poly(4-vinylpyridine) quaternized with poly(ethylene oxide) side chains

A new type of single-ion conductor with fixed cation was synthesized by spontaneous anionic polymerization of 4-vinylpyridine in the presence of short polyethylene oxide (PEO) chains as alkylating agents. These comblike polymers have low Tgs and are amorphous with the shorter PEOs. Their conductivities are unaffected by the nature of the anion (Br−, ClO4−, and tosylate) and are controlled by the free volume and the mobility of the pendant cation. By comparison of the results at constant free volume, it is shown that the charge density decreases with the increasing length of pendant PEO demonstrating that PEO acts only as a plasticizing agent. Best conductivity results (σ = 10−5 S cm−1 at 60°C) are obtained with PEO side chains of molecular weight 350. With this sample, the conductivity in the presence of various amounts of added salt (LiTFSI) was studied. A best value of 10−4 S cm−1 at 60°C is obtained with a molar ratio EO/Li of 10. It is shown that, over the range of examined concentrations (0.2–1.3 mol Li kg−1), the reduced conductivity σr/c increases linearly with increasing salt concentration showing that the ion mobility increases continuously. Such behavior is quite unusual since in this concentration range a maximum is generally observed with PEO systems. To interpret this result and by analogy with the behavior of this type of polymer in solution, it is proposed that the conformation of these polymers in the solid state is segregated with the P4VP skeleton more or less confined inside the dense coils surrounded by the PEO side chains. Under the influence of the increasing salt concentration, this microphase separation vanishes progressively: The LiTFSI salt exchanges with the tosylate anions and acts as a miscibility improver agent. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2719–2728, 1997