Wholly aromatic polyamides by the direct polycondensation reaction using triphenyl phosphite in the presence of poly(4-vinylpyridine)

The polycondensation reaction of aromatic dicarboxylic acids and diamines by using triphenyl phosphite were carried out in N-methylpyrrolidone (NMP) in the presence of poly(4-vinylpyridine) (P4VP). The reaction, especially of terephthalic acid (TPA), was markedly facilitated to give the absence of P4VP. The reaction promoted by P4VP was further favored by the addition of various pyridine derivatives; of the pyridines examined, pyridine was most effective, giving the best results at a high level (pyridine/P4VP values up to 26). P4VP of the molecular weight in the range of 1.3 × 10⁴?3.0 × 10⁵ did not affect the viscosity of the resulting polymer. These favorable additive effects of P4VP on the reaction of TPA were not observed in the reactions of isophthalic acid, and m -and p-aminobenzoic acids.     

Multifunctional hydrolytic catalyses. IX. Hydrolysis of p-nitrophenyl acetate by bifunctional polymer catalysts containing zwitterionic (hydroxamate) nucleophiles

The hydrolysis of p-nitrophenyl acetate by bifunctional polymer catalysts was studied in 28.9% EtOH–H₂0 at 30°C. Partial (ca. 10 mole%) quaternization of poly(4-vinylpyridine) and poly(1-vinyl-2-ethylimidazole) with benzyl N-benzyl chloroacetohydroxamate and the subsequent removal of the benzyl group produced water-soluble polymers containing zwitterionic hydroxamate groups and free pyridine (or imidazole) groups. The zwitterionic hydroxamate was a nucleophile more than 10 times as effective as simple hydroxamate anions, and the acetyl hydroxamate intermediate was efficiently hydrolyzed by the intrapolymeric pyridine (or imidazole) group. Thus, the catalytic efficiency of these bifunctional polymers was much better than monofunctional polymers which contain either hydroxamate or imidazole, and amounted to 10–20% of that of α-chymotrypsin under a comparable condition.     

Reactions on polymers with amine groups. V. Addition of pyridine and imidazole groups with acetylenecarboxylic acids

Unsaturated macromolecular carboxybetaines were obtained by reaction of poly(4-vinylpyridine) and poly(N-vinylimidazole) with propiolic acid. A kinetic model was presented for 4-methylpyridine. It consists of three coupled reactions: neutralization, addition which involves two molecules of acid and leads to a cation–anion pair structure, where the cation results from the addition of the amine nitrogen to the triple bond of acid, and an equilibrium reaction between the ion-pair structure and the betaine structure. The addition rate was found to be higher for poly(4-vinylpyridine) than for poly(N-vinylimidazole); it was also higher in water than in a water–methanol mixture. The reaction with acetylenedicarboxylic acid was carried out on poly(N-vinylimidazole), but the transformed units showed the structure that results from propiolic acid. The betaine products from 4-methylpyridine did not polymerize by radical initiation. The polymeric products show characteristics of photocrosslinking polymers. © 1998 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 36: 1615–1623, 1998     

Preparation of monodisperse polymer particles from 4-vinylpyridine

Dispersion polymerization of 4-vinylpyridine was performed by using polystyrene-block-polybutadiene as stabilizer in a mixture of N,N-dimethylformamide (DMF) and toluene to produce polymer particles. The weight ratio of the solvents affects the particle size and dispersity. In the range of DMF content from 5 to 20 wt.-%, uniform particles of a diameter of ca. 1 μm were obtained. The present system was expanded to the preparation of monodisperse particles of poly[(4-vinylpyridine)-co-(methacrylic acid)].     

Oxidation of Hydroquinone By (N-Vinylpyrrolidone)-(4-Vinylpyridine) Block and Graft Copolymers

ABSTRACT

A-B Type block copolymer of N-vinylpyrrolidone (NVP) and 4-vinylpyridine (VPy) [poly(NVP-b-VPy) and graft copolymers of VPy onto copolymers of NVP with 4-vinylbenzyl N,N-diethyldithiocarbamate (VBDC) [poly(NVP-g-VPy) were synthesized by the iniferter method. the compatibility between NVP and VPy units in the copolymers was evaluated from the glass transition temperature of these copolymers. Hydroquinone was then oxidized by the synthesized NVP-VPy copolymers-Cu(II) complex catalysts. the influence of the distribution of each monomer unit in copolymers on the catalytic activity was studied by comparing the activity of these copolymers. the catalytic activity of these copolymers increased in the order: NVP-VPy blend polymer, poly(NVP-b-VPy), poly(NVP-g-VPy), random copolymer [poly(NVP-ran-VPy)]. This order parallels the compatibility between NVP units and VPy units in these copolymers.     

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.     

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.     

Site-Site Interactions in a Polymer Matrix. Functionalization of Pyridine Rings with Dibromoalkanes in Crosslinked Poly(Styrene-CO-4-Vinylpyridine)

Pyridine ring functionalization and additional crosslinking in crosslinked poly(styrene-co-4-vinylpyridine) with various dibromoalkanes depend on the chain length of the dibromoalkane, the solvent polarity, and the molar ratio between the pyridine rings and the dibromoalkane. the effect of chain length on additional crosslinking becomes more pronounced when the good swelling solvent dimethylformamide is replaced by dibromoalkane. on the other hand, the degree of crosslinking of poly(styrene-co-4-vinylpyridine) influences both the reactivity and the additional crosslinking.     

Miscibility and Thermal Behaviour of Poly(styrene-co-itaconic acid)/Poly(butyl methacrylate-co-4-vinylpyridine) Mixtures. Accessibility and Self-Association Effects

Summary: The miscibility and thermal behaviour of binary mixtures of poly(styrene-co-itaconic acid) containing 11 or 27 mol % of itaconic acid (PSIA-11 or PSIA27) with poly(butyl methacrylate) (PBMA)or poly(butyl methacrylate-co-4-vinylpyridine) containing 10 or 26 mol% of 4-vinylpyridine (PBM4VP-10, PBM4V-P26) were investigated by differential scanning calorimetry, scanning electron microscopy, FTIR spectroscopy and thermogravimetry. The results showed that 11 mol % of itaconic acid and 10 mol % of 4-vinylpyridine respectively introduced within the polystyrene and poly(butyl methacrylate) matrices induced the miscibility of this pair of polymers due to specific interactions of hydrogen bonding type with partial pyridine protonation that occurred between the two copolymers as evidenced by FTIR from the appearance of two new bands at 1607 cm⁻¹ and 1640 cm⁻¹. Increasing itaconic acid content from 11 to 27 mol % led to a decrease of the intensity of the specific interactions within PSIA-27/PBM4VP blends and is attributed to both accessibility and self association effects as evidenced by DSC from the change of the shape of the Tg- composition curves and by FTIR spectroscopy. As shown from the thermogravimetric study, the presence of these specific interactions delayed the anhydride formation and improved the thermal stability of the blends.     

Dynamic mechanical behavior and optical limiting property of multifunctional fullerenol/polymer composite

The dynamic mechanical behavior of materials based on multifunctional fullerenol and poly(styrene-co-4-vinylpyridine)/poly(styrene-co-butadiene) matrix was studied. The interaction between the hydroxyl group of fullerenol and the pyridine group as evidenced by X-ray photoelectron spectroscopy results in a significant increase of the storage modulus. The optical limiting property of fullerenol was studied at 532 nm with nanosecond laser pulses. The optical limiting performance of fullerenol, which is poorer than its parent C₆₀, is slightly improved upon the incorporation of poly(styrene-co-4-vinylpyridine).     

Quenching of photo-excited state of copolymer pendant Ru(bpy) complexes with methylviologen

Copolymer pendant tris(2,2′-bipyridine)ruthenium(II) complexes were prepared from the copolymers of 4-methyl-4′-vinyl-2,2′-bipyridine with styrene, acrylic acid, methyl methacrylate, hydroxyethyl methacrylate, acrylonitrile, N-vinylpyrrolidone, 4-vinylpyridine, and quaternized 4-vinylpyridine. The quenching of the photo-excited state of the polymer complexes by methylviologen was studied. Pendant anionic groups such as acrylate enhanced remarkably the quenching of the cationic sensitizer by the cationic substrate, however, pendant cationic groups such as quaternized pyridine did not affect the reaction. The polymer chain showed generally retarding effect on the quenching reaction.     

Syntheses and reactions of optically active polymers. II. Preparations of optically active polymers containing quinine,L-ephedrine,and L-histidine residues and their reactions with α-cyanoethylaquocobaloxime

Preparations of polymers with bis(dimethylglyoximato)cobalt (cobaloxime) were investigated. 4-Vinylpyridine was reacted with α-cyanoethylaquocobaloxime to produce α-cyanoethyl-4-vinylpyridinatocobaloxime (I) in 72% yield. It did not, however, polymerize by the use of azobisisobutyronitrile (AIBN) as an initiator. Polymers containing α-cyanoethylcobaloxime were obtained by reactions of polymers with α-cyanoethylaquocobaloxime (II). Poly(9-O-methacryloylquinine) (III), poly(O-methacryloyl-N-methyl-L -ephedrine) (IV), poly[N^α-(o-vinylbenzyl)-L -histidine] (V), and poly(4-vinylpyridine) (VI) were prepared and used in these reactions. Polymers V and VI were reacted with II to give polymers X, XI, XII, and XIII containing α-cyanoethylcobaloxime.     

Oligomerization of vinyl monomers 18. Stereochemistry of anionic oligomerization of 4-vinylpyridine

Oligomers of 4-vinylpyridine were prepared by reaction in vacuo of 4-vinylpyridine with lithio-4-ethylpyridine at ?78°C, followed by reaction with CH₃I(¹³CH₃I) or CH₃OH. The stereochemistry was studied by NMR and GC. Methylation and the addition of 4-vinylpyridine occurred in a stereochemically nonselective manner. The data also indicated that in contrast to the oligomerization of 2-vinylpyridine the stereoisomeric meso and racemic 4-pyridyl carbanions propagated with equal reaction rates. The stereochemistry was readily explained by an absence of coordination of the Li ion by the nitrogen of the penultimate pyridine ring observed in the corresponding oligomerization of 2-vinylpyridine.     

1,3-Dipolar cycloaddition reaction of aryl nitrile oxides with alkenes using imidazole and pyridine containing reusable polymeric base catalysts

Cross-linked poly-1-(4-vinylbenzyl)imidazole and cross-linked poly-4-vinylpyridine have been prepared from respective vinyl monomers using different quantities of divinylbenzene as a cross-linker by radical polymerization. The polymeric bases were characterized by FT-IR, TGA, field emission-scanning electron microscopy (FE-SEM), and Brunauer-Emmett-Teller (BET) surface area analysis. Their swelling behavior was also studied. They were used as base catalysts for 1,3-dipolar cycloaddition reaction of aryl nitrile oxides, generated in situ from N-hydroxyimidoyl chloride, with N-phenylmaleimide and ethyl acrylate, to obtain 3-arylisoxazolines. Both the bases gave excellent results. These polymers were reusable, safe to use, and provided good alternative for organic nonreusable bases like pyridine and triethylamine which are hazardous.     

Novel poly(pyridine imide) with pendent naphthalene groups: Synthesis and thermal,optical, electrochemical,electrochromic, and protonation characterization

A new diamine containing a pyridine heterocyclic group and a naphthalene substituent, 4-(2-naphthyl)-2,6-bis(4-aminophenyl) pyridine (NBAPP), was synthesized with the Chichibabin reaction and used in the preparation of poly(pyridine imide) by direct polycondensation with 4,4′-hexafluoroisopropylidenediphathalic anhydride in N-methyl-2-pyrrolidinone (NMP). The poly(pyridine imide) derived from diamine NBAPP with naphthalene substituents was highly organosoluble: it was soluble in tetrahydrofuran, NMP, N,N-dimethylacetamide (DMAc), N,N-dimethylformamide, and γ-butyrolactone at room temperature and in pyridine, dimethyl sulfoxide, and cyclohexanone upon heating at 70 °C. The poly(pyridine imide) was converted into lightly colored, optically transparent, flexible, and tough polyimide films via casting onto glass from a DMAc solution. This polymer exhibited good thermal stability (temperature of 10% weight loss = 527 °C) in air and high dielectric constants (as high as 4.20 at 1 kHz). The polyimide films had a tensile strength of 102 MPa and a tensile modulus of 1.8 GPa. As for the optical properties, the polymer exhibited UV–vis absorption bands in the region of 223–450 nm and possessed strong green-yellow fluorescence (500 nm) after being protonated with acid. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 2367–2374, 2007     

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.     

Investigation of Hydrogen Bonded Interpolymer Complexes Based on Poly (n-butyl methacrylate–co-methacrylic acid) and Poly (n-butyl methacrylate -co-4-vinyl pyridine). Temperature Effect

Summary: Two kinds of interpolymer complexes as soluble or precipitate of different structures were obtained in both THF and butan-2-one as common solvents by monitoring the hydrogen-bonding density within homoblends of poly(n-butyl methacrylate-co-4-vinylpyridine) (BM4VP) and poly(n-butyl methacrylate-co-methacrylic acid) (BMMA). A viscometry study confirmed such differences between these two types of interpolymer complexes from the behavior of the reduced viscosity of their blend solutions with feed blend composition. Qualitative and quantitative analyses of the interactions that occurred between these copolymers of relatively bulky side chain length containing various amounts of methacrylic acid and 4-vinylpyridine were carried out by FTIR. The fraction of associated pyridine groups to the carboxylic groups of the BMMA increases as the content of these latter increases in the BMMA/BM4VP blends. The obtained results also showed that the fractions of associated pyridine within the BMMA25/BM4VP26 blends are higher than those within BMMA18/BM4VP19 or BMMA8/BM4VP10. The FTIR analysis of a selected BMMA18/BM4VP19 1:1 ratio, carried out from 80 °C to 160 °C, above the glass transition temperatures of the two constituents of the blend, confirms the presence of strong hydrogen bonding interactions between the pyridine and the carboxylic groups within these blends even at 160 °C. A LCST is expected to occur at higher temperature as shown from the progressive decrease of the fraction of the associated pyridine.     

Effect of metal salts on polymerization. Part I. Polymerization of vinylpyridine initiated with cupric acetate

The polymerization of vinylpyridine initiated by cupric acetate has been studied. The rate of polymerization was greatly affected by the nature of the solvent. In general polar solvents increased the rate of polymerization. Polymerization was particularly rapid in water, acetone, and methanol. The initial rate of polymerization of 4-vinylpyridine (4-VP) in a methanol–pyridine mixture at 50°C. is R_p = 6.95 × 10^?6[Cu¹¹]^1/2 [4-VP]² l./mole-sec. The activation energy of initiation by cupric acetate is 5.4 ± 1.6 kcal./mole. Polymerization of 2-vinylpyridine and 2-methyl-5-vinylpyridine with the same initiator was much slower than that of 4-VP. Dependence of R_p on monomer structure and solvent is discussed. Kinetic and spectroscopic studies led to the conclusion that the polymerization of 4-VP is initiated by one electron transfer from the monomer to cupric acetate in a complex having the structure, (4-VP)₂Cu(CH₃COO)₂.     

Coenzyme models. 15. A polymeric model system for the NADH-dependent dehydrogenase enzymes

Copolymers of 4-vinylpyridine (4-VP) and N-(p-vinylbenzyl)-1,4-dihydronicotinamide (VNicH) were synthesized, and a carbonyl substrate (benzil) was reduced to alcohol in an aqueous ethanol solution in the absence and presence of metal ions (Zn²⁺ and Ni²⁺) as part of a model study of NADH-dependent enzymes. The reduction rates by VNicH in polymers were four to seven times greater than that of the corresponding monomeric analog (N-benzyl-1,4-dihydronicotinamide). Added metal ions catalyzed the reduction by VNicH-29 (VNicH content, 29 mole%) but inhibited the reduction by VNicH-9 (VNicH content, 9 mole%). It was suggested that metal catalysis occurs only when metal ions are bound closely near the dihydronicotinamide moiety.     

Controlled radical polymerization of 4-vinylpyridine

2,2,6,6-Tetramethylpiperidine-N-oxyl (TEMPO)-mediated free radical polymerization of 4-vinylpyridine is found to proceed in a “controlled” manner. A linear increase of molecular weight along with an increase in conversion occurs at varying temperatures. Polymerization of styrene with a poly(4-vinylpyridine) block as macromer results in block copolymers with narrow polydispersity. The polymers are characterized by different size exclusion chromatography methods and converted to cationic polyelectrolytes as well as to polysulfo- and polycarbobetaines.