Low-Temperature Curing of Poly[N-methyl(allyl)-5-vinyltetrazole]

Low-temperature curing of poly[N-methyl(allyl)-5-vinyltetrazole) with 1,3-dicyano-2,4,6-triethylbenzene N,N'-dioxide was studied.     

Mutual Transformations of Isomers in N-Methyl-5-vinyltetrazole Copolymers

Mutual transformations of N ¹ and N ² isomeric derivatives of 5-vinyltetrazole polymers in the absence of a solvent were studied.     

Synthesis and Absorption Power of New Polyelectrolyte Tetrazole-Containing Acrylic Hydrogels

The kinetic features of formation and equilibrium swelling in water and aqueous solutions of metals were considered for new hydrogels based on acrylic acid and methylenebisacrylamide modified with 2-methyl-5-vinyltetrazole in the polymerization stage. The influence of the concentration of the reactants on the gelation rate and the degree of equilibrium swelling was studied, as well as the influence of 2-methyl-5-vinyltetrazole on the properties of the copolymers prepared. Possible application fields for the new hydrogels were proposed.     

Compatibility of copolymers of N-vinylcaprolactam and vinyltetrazoles with aqueous systems

Radical polymerization of N-vinylcaprolactam with 5-vinyl- and 2-methyl-5-vinyltetrazole was used to synthesize water-compatible polymeric products whose aqueous solutions have phase diagrams with a lower critical solution temperature. The thermodynamics of the interaction of the copolymers with water and their behavior in aqueous systems were studied.     

Influence of the cross-link structure on the behavior of hydrogels of network poly-5-vinyltetrazole in aqueous media

The swelling in aqueous media of network poly-5-vinyltetrazole synthesized by various procedures using low-molecular-weight, oligomeric, and polymeric cross-linking agents was studied.     

Synthesis and properties of tetrazole-containing double polymers

Based on poly(5-vinyltetrazole) and a copolymer of 2-methyl-5-vinyltetrazole with 2-(vinyloxyethoxy)methyloxirane, tetrazole-containing network double polymers capable of gelation both in organic media and in water have been obtained. It has been shown that the covalent bonding of linear polymer macromolecules is the result of alkylation of unsubstituted N-H tetrazole cycles of poly(5-vinyltetrazole) with oxirane cycles incorporated into the copolymer structure.     

Composites based on vinyl tetrazole-acrylate copolymers and hollow glass spheres

Hydrogel composites based on sodium acrylate, 2-methyl-5-vinyltetrazole, and N, N- methylenebisacrylamide, modified with hollow glass spheres during radical polymerization were prepared and studied. The influence of the modifying additives on the physicochemical properties of the composites was elucidated. A mechanism of modification of vinyl tetrazole-acrylate copolymers with hollow glass spheres was suggested. The materials synthesized are suitable for preparing articles with desired shape and good performance characteristics.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 10, 2004, pp. 1719–1721.Original Russian Text Copyright ¢ 2004 by Uspenskaya, Sirotinkin, Masik.     

Influence of the structure of oxirane-containing compounds on curing of poly-<Emphasis Type="Italic">N</Emphasis>-methyl-5-vinyltetrazole

Comparative analysis of the curing performance of epoxy-containing cross-linking agents of different structure in vulcanization of a promising binder for energetic systems, poly-N-methyl-5-vinyltetrazole prepared by the modification procedure and containing residual N–H-unsubstituted tetrazole fragments, was made. Cross-linking of polymer chains of the binder is a result of alkylation of the residual N–H-unsubstituted tetrazole rings in poly-N-methyl-5-vinyltetrazole macromolecules with oxirane rings of the second reactant. Curing of poly-N-methyl-5-vinyltetrazole in the presence of macromolecular curing agents, carbon-chain polymers containing oxirane rings in pendant chains, at temperatures lower than 100°С occurs in a considerably narrower time interval compared to curing with low-molecular-mass epoxy resin.     

Synthesis of crosslinked poly(5-vinyltetrazole) and properties of hydrogels formed on its basis

Crosslinked polymer samples are synthesized through the alkylation of linear poly(5-vinyltetrazole) with di- and multifunctional compounds containing mobile halogen atoms or oxirane cycles. In the ionized state, the crosslinked poly(5-vinyltetrazole) shows limited swelling ability in water and forms hydrogels. It is demonstrated that tetrazole-containing hydrogels may serve as matrices for stabilization of nanosized metal particles.     

Synthesis and electrochemical applications of fluorinated vinylazole copolymers for monitoring NO in model and biological systems

Copolymers of 1-vinyl-1,2,4-triazole and 5-vinyltetrazole with 1,1,5-trihydrooctafluoropentyl methacrylate and 1,1,7-trihydrododecafluoroheptyl methacrylate were prepared under the conditions of radical initiation. These copolymers were used for modification of the surface of a glassy carbon electrode, and the effect of the modification on the electrochemical behavior of the electrode in anodic oxidation of dopamine and NO was studied. The possibility of enhancing the selectivity of the electrochemical sensor for monitoring NO in biological media was demonstrated.     

The thermodynamic properties of 5-vinyltetrazole and poly-5-vinyltetrazole over the temperature range from <Emphasis Type="Italic">T</Emphasis> → 0 to 350 K

The temperature dependences of the heat capacities of 5-vinyltetrazole and poly-5-vinyltetrazole were measured by adiabatic vacuum calorimetry over the temperature range 6-(350–370) K with errors of ～0.2%. The results were used to calculate the thermodynamic functions of the compounds, C _p ^° , H ^°(T) - H ^°(0), S ^°(T), and G ^°(T) - H ^°(0), over the temperature range from T → 0 to 350–370 K. The energy of combustion of 5-vinyltetrazole and poly-5-vinyltetrazole was measured in an isothermic-shell static bomb calorimeter. The standard enthalpies of combustion Δ _c H ^° and thermodynamic characteristics of formation Δ_f H ^°, Δ_f S ^°, and Δ_f G ^° at 298.15 K and p = 0.1 MPa were calculated. The results were used to determine the thermodynamic characteristics of polymerization of 5-vinyltetrazole over the temperature range from T → 0 to 350 K.     

Interaction of 5-vinyltetrazole with triethylamine

It was shown by the methods of UV spectrophotometry, conductometry, viscosimetry, and PMR spectroscopy that the interaction of 5-vinyltetrazole with triethylamine gives a polymeric salt of vinyltetrazole.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 994–995, July, 1984.     

Thermodynamics of water interaction with 5-vinyltetrazole copolymers with different hydrophilic-hydrophobic balances

The thermodynamics of interaction with water and the behavior of 5-vinyltetrazole copolymers with comonomers of different chemical natures and hydrophilicities in aqueous media have been studied. It has been shown that the presence of side perfluoroalkyl and disubstituted tetrazole fragments, which ensure a strong self-association of polymer chains in copolymer macromolecules, favors a greater decrease in water affinity of polymers compared to the effect of hydrophobic alkyl substituents.     

Complexes of poly-5-vinyltetrazoles with weak polybases

Formation of interpolymer complexes of poly(5-vinyltetrazole) and poly(5-izopropenyltetrazole) with poly(acrylamide), poly(ethylene oxide), poly(1-vinylpyrrolidone), and poly(1-vinyl-1,2,4-triazole) was investigated by potentiometry and viscometry. The reduced activity of tetrazol-containing polyacids in reaction with poly(1-vinylpyrrolidone) from polyacrylic polyacids was explained by steric hindrances at the expense of bulky tetrazolic rings. There is a strong system of hydrogen bonds in the poly(5-vinyltetrazole) solution that leads to decreasing of its activity in the complexation in comparison with poly(5-izopropenyltetrazole). Hydrophobic interactions between methyl groups of poly(5-izopropenyltetrazole) lead to additional stabilization of the complexes at low degrees of ionization and to fast destruction of them at ionization degrees corresponding to destruction of the compact conformation of poly(5-izopropenyltetrazole) (α = 0.2–0.4). Interaction of poly(5-vinyltetrazole) with poly(1-vinyl-1,2,4-triazole) at elevated pH leads to an interpolymer complex stabilized by donor–acceptor interactions between the π-systems of tetrazolate anions and triazole rings. © 1996 John Wiley & Sons, Inc.     

Structure of Free Radicals Formed under X-ray Irradiation of Organic Polymeric Acids

The structure of free radicals formed under X-ray irradiation of polyacrylic and polymetharcylic acids and poly-3-vinyltetrazole was studied by ESR spectroscopy. In polymerization of polymethacrylic acid, the conditions of the polymer recovery from the solution affect the nature of the radiolysis products.     

Copolymerization of 5-vinyltetrazole with N-vinyllactams and properties of the copolymers

Polymer polyelectrolytes soluble in water in the ionized state are obtained by the free-radical copolymerization of 5-vinyltetrazole with N-vinylcaprolactam, N-vinylpiperidone, and N-vinylpyridone. The aqueous solutions of 5-vinyltetrazole-N-vinylcaprolactam copolymers are pH-thermosensitive and can be described by phase diagrams with a lower critical solution temperature.     

Vinyltetrazoles: I. Synthesis of NH-unsubstituted 5-vinyltetrazole

The NH-unsubstituted 5-vinyltetrazole was obtained in 55% yield by exhaustive methylation of 5-(β-dimethylaminoethyl)tetrazole with dimethyl sulfate at the terminal dimethylamino group with the subsequent elimination of a proton from the α-CH₂ group and Hofmann β-cleavage of the intermediate 5-(β-trimethylammoniumethyl)tetrazolide methyl sulfate. The microwave irradiation was shown to reduce 5-fold the time of the synthesis of the initial substrate, 5-(β-dimethylaminoethyl)tetrazole.     

A novel and convenient preparation of antibacterial polyacrylonitrile nanofibers via post-modification using nitrile click chemistry and electrospinning

An efficient, novel and convenient method for the synthesis of modified polyacrylonitrile (PAN) with antibacterial property is reported. The modification of PAN was prepared by a nitrile click chemistry reaction with sodium azide (NaN₃) and silver nitrate (AgNO₃) as catalyst to yield antibacterial polymeric materials with 5-vinyltetrazole units. The results showed that 5-vinyltetrazole units had coordinated with silver ion (Ag⁺). Through the electrostatic spinning technology, the post-modification PAN nanofibers (PAN–Ag⁺ nanofibers) were prepared and the fibers were tested for their antimicrobial properties by the bacterial infection experiment. Afterwards, the antibacterial and stable performance of different proportions of silver ions in PAN nanofibers has been compared. The PAN–Ag⁺ nanofibers are characterized for mechanical and thermomechanical properties, structural analysis, appearance characteristics, as well as the antibacterial properties. And the nanofibers exhibit marvelous chemical stability according to the thermogravimetric analysis. When at 800 °C, the PAN decomposed about 60%, while the decomposition of the PAN–Ag⁺s was 40%. Based on the bacterial infection experiment, PAN–Ag⁺ nanofibers’ antibacterial properties were stronger with the increase of silver ions, such as the number of bacteria clone was smaller and the bacteriostatic ring was larger. Hence, with combination of silver ions, the final polymers show strong antimicrobial properties.     

Preparation and reactivity of metal-containing monomers

Metal-containing monomers based on vinyl derivatives of heterocycles (4-vinylpyridine, 3,5-dimethyl-1-vinylpyrazole, 2-methyl-5-vinyltetrazole) and NiCl₂, CoCl₂, CrCl₃ have been prepared and characterized by chemical analysis, IR and electron spectroscopy. By means of spectral methods, the complex formation has been shown to involve N atom of the heterocycle, while the exocyclic C = C bond does not participate in the process. The structure of polyhedrons formed has been characterized both in the solid state and in methanol or DMF. The comparison of splitting parameters for different symmetries indicates that in passing from five-membered to six-membered vinylheterocycles, the strength of the ligand field is greatly enhanced.For part 24, seeIzv. Akad. Nauk, Ser. Khim., 1992, 2066 [Bull.Russ.Acad.Sci.Div.Chem.Sci., 1992,41, 1609].Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 76–80, January, 1993.     

Vinyltetrazoles: III. Metal-catalyzed arylation, a new method of vinyltetrazoles functionalization

New functionalization procedure was developed for C- and N-vinyltetrazoles based on Heck reaction. Applying this method diverse (E)-styryl- and (E)-distyryltetrazoles were obtained for the first time in 76?C85% yields. C-Vinyltetrazoles are more reactive in Heck cross-coupling than N-vinyltetrazoles. The arylation of 1-vinyltetrazole along Heck reaction proceeds with a C-H-activation and leads to the formation of 5-phenyl-1-[2-(E)-phenylethenyl]tetrazole.