Radical Polymerization Of 4-vinylpyridine Research Articles

Synthesis of bactericidal polymer coatings by sequential plasma-induced polymerization of 4-vinyl pyridine and gas-phase quaternization of poly-4-vinyl pyridine

Plasma-based technology is an alternative to produce universal polymer coatings with the appropriate requirements of robustness and stability for antibacterial applications. Here, we proposed a sequential two-step alternative to synthesize antibacterial polymer coatings. A non-isothermal plasma reactor, operated at atmospheric pressure (Patm) and room temperature (Troom), was used to induce free radical polymerization of 4-vinyl pyridine (4VP) on high-density polyethylene (PE). In a subsequent step, the poly-4VP (P4VP) films were treated with a bromoethane/He gas stream to produce quaternized P4VP (P4VPQ) films. Chemical structure of polymer films was validated by infrared and UV–visible spectroscopy, and morphology was evaluated by optical and atomic force microscopy; scanning electron microscopy was used to determine films thickness, which was then used to estimate the surface charge density. The bactericidal capacity was determined with a standard test by using Escherichia coli. Both types of films had an estimated charge density in the order of 1016 positive charges per cm2; P4VP films removed about 95–99% of bacteria, whereas 4PVPQ films eliminated 100%. The methodology proposed for the synthesis of antibacterial polymer coatings is simpler, faster, and more environmentally friendly than other plasma-based methods; operation at Troom and Patm may also have a significant effect on the economics and the ease of implementation of the process at commercial scale. The suggested approach may facilitate the development of new universal coatings, and operating plasma conditions could be extrapolated for engineering antibacterial coatings in industrial areas where bacterial attachment is of concern.

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.

Stereoregular control of poly(4-vinyl pyridine) on free radical polymerization by using the inclusion complex with randomly methylated β-cyclodextrin

Highly heterotactic poly(4-vinyl pyridine)s (P4VPs) with the fraction of mr content (fmr) > 0.81 were synthesized by free radical polymerization of 4-vinyl pyridine (4VP) with randomly methylated β-cyclodextrin (β-RMCD) in acidic aqueous media of HNO3 and CF3COOH at 40 °C. The heterotacticity of P4VP strongly depended on the neutralization of 4VP. The complete neutralization of 4VP with HNO3 or CF3COOH increased the heterotacticity of P4VP, whereas atactic P4VP was obtained in water. The partial decomposition of β-RMCD by HCl reduced the heterotacticity of P4VP (fmr ≈ 0.74). The structures of inclusion complexed monomers were determined by Job's plot, 2D NMR with nuclear Overhauser enhancement spectroscopy analyses, and simulation by MM2. The 1:2 complex with [β-RMCD]:[4VP] with meso placement of 4VPs in β-RMCD was formed when 4VP was completely neutralized with acid, whereas the 1:1 complex was formed in water. The mechanism of heterospecific control by using β-RMCD was proposed. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012

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.

Synthesis and properties of a polyrotaxane network prepared from a Pd-templated bis-macrocycle as a topological cross-linker

Polyrotaxane networks (PRNs) were synthesized by exploiting a Pd-templated bis-macrocycle as a topological cross-linker during radical polymerization of a vinyl monomer. The bis-macrocycle (9) was prepared by combining two macrocycles with a linear linker. Radical polymerization of 4-vinylpyridine in the presence of 9 and a catalytic amount of 2,2′-azobisisobutyronitrile (AIBN) yielded a gelled polymer. The addition of 4-tert-butylstyrene as a vinyl co-monomer to the polymerization system afforded a sufficiently stable gel as the PRN, clearly indicating that 4-tert-butylstyrene was successfully introduced as end-capping moieties of the trunk polymer. The swelling properties of the PRN were evaluated using several solvents. The topological structure and swelling properties of the PRNs were confirmed by a control experiment using a bis-acyclic pincer-type Pd complex (13) as a cross-linker.

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”

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.

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.

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.

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.

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%).

Poly(N‐vinyl pyrrolidone) as a template for the radical polymerization of 4‐vinyl pyridine

AbstractThe coefficient of interaction between poly(N‐vinyl pyrrolidone) and poly(4‐vinyl pyridine) is determined in solutions of the mixture of these two polymers in different solvents. The results show the complexation of the polymers. Maximum complexation occurred at molar ratio 1:1. The kinetics and mechanism of polymerization of 4‐vinyl pyridine in dimethylformamide with poly(N‐vinyl pyrrolidone) as a template is investigated.