Search results for "monomer"

Influence of chloride anions on the electrodeposition and electroactivity of the polymer matrix in polypyrrole, poly( N -methylpyrrole) and polypyrro…

2004

We report electrochemical studies on the influence of a small concentration of chloride ions on the electroactivity of the polymer matrix of polypyrrole (PPy), poly(N-methylpyrrole) [p(N-MePy)] and a poly(titanocene-propyl-pyrrole) derivative, p(Tc3Py) [Tc(CH2)3NC4H4; Tc=CpCp′TiCl2; Cp=C5H5; Cp′=C5H4] in acetonitrile (AN), tetrahydrofuran (THF) and N,N-dimethylformamide (DMF). The polymer films were obtained on Pt disc electrodes from AN solutions of the monomers containing 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF6) as the supporting electrolyte and then transferred to the corresponding monomer-free solution. Studies in Cl−-containing solutions have shown that the p(Tc3Py) matrix…

N-Alkyl Ammonium Resorcinarene Chloride Receptors for Guest Binding in Aqueous Environment

2016

Host systems with guest binding ability in water and/or biological fluids are a current challenge in supramolecular host–guest chemistry. Here we present the first syntheses of water-soluble N-ethanol ammonium resorcinarene chlorides (NARCls) with terminal hydroxyl groups at the upper rim. The NARCls possess deep cavities and are shown to bind a variety of guest molecules such as linear and cyclic alkanes, linear halogenated alkanes, and aromatic fluorophores (naphthalene, p-(phenylazo)phenol) in water through hydrophobic interactions, as well as 1,4-dioxane (a water soluble guest) via hydrogen bonds. The receptors are monomeric in aqueous media and form 1:1 host–guest complexes with bindin…

Matrix-isolation and ab initio study of the complex between formic acid and xenon

2012

Abstract We report on the identification of the complexes of formic acid (FA) and Xe in an argon matrix. The geometries, interaction energies, reaction barriers, and vibrational spectra of the FA⋯Xe complexes are calculated at the MP2 level of theory. The calculations reveal four structures for the trans-FA⋯Xe complex and four structures for the cis-FA⋯Xe complex. In the experiments, two structures of the trans-FA⋯Xe complex are observed after deposition of FA/Xe/Ar matrices, with and without OH⋯Xe interaction (H-bonded and non-H-bonded structures). The cis-FA⋯Xe complex was synthesized by vibrational excitation of the non-H-bonded trans-FA⋯Xe complex. The non-H-bonded and H-bonded structur…

Cure kinetics of a cobalt catalysed dicyanate ester monomer in air and argon atmospheres from DSC data

2004

A kinetic analysis of the cyclotrimerisation reaction of a dicyanate ester monomer catalysed by cobalt(II) acetylacetonate and nonylphenol in air and argon atmospheres has been carried out by differential scanning calorimetry (DSC). Dynamic and isothermal DSC scans as well as the glass transition temperature are the experimental data obtained. From isothermal scans a higher cyanate conversion in air than in argon was obtained. The cyanate conversions are satisfactorily described with a second-order kinetic equation in the kinetically controlled region, and by m-order (m<1) equation after vitrification is reached. Activation energies determined by different procedures agree among them, showi…

1986

The kinetics of polyamidation was investigated for the reaction of diphenyl terephthalate as activated diester with trimethylhexamethylenediamine (1 : 1 mixture of 2,2,4- and 2,4,4-trimethyl isomers) in dimethyl sulfoxide. The good solubility of the resulting polyamide (Trogamid®(poly(iminoterephthaloylimino-x,y,z-trimethylhexamethylene))) assured a reaction in which all reactants, especially the polyamide, were soluble. The conversion was followed by analysis of the phenol set free and by measuring the number-average degree of polymerization Pn of the polyamide. The reaction obeyed an overall second order with the principle of equal reactivity of functional groups fulfilled for Pn ≿ 16. De…

1986

The aminolysis of diphenyl terephthalate by means of hexylamine was studied in dimethyl sulfoxide as a model reaction for polyamidation. The kinetic analysis showed that the two ester groups of the diphenyl ester do not react independently. Furthermore, the reaction of the first ester group was of mixed second and third order, while the reaction of the second ester group contained only a second order term. The rate constants found were used to determine the Arrhenius activation parameters.

A predictive model for salt nanoparticle formation using heterodimer stability calculations

2021

Acid–base clusters and stable salt formation are critical drivers of new particle formation events in the atmosphere. In this study, we explore salt heterodimer (a cluster of one acid and one base) stability as a function of gas-phase acidity, aqueous-phase acidity, heterodimer proton transference, vapor pressure, dipole moment and polarizability for salts comprised of sulfuric acid, methanesulfonic acid and nitric acid with nine bases. The best predictor of heterodimer stability was found to be gas-phase acidity. We then analyzed the relationship between heterodimer stability and J4×4, the theoretically predicted formation rate of a four-acid, four-base cluster, for sulfuric acid salts ove…

Functionalization using biocompatible carboxylated cyclodextrins of iron-based nanoMIL-100

2021

9 pags., 7 figs., 1 tab.

1986

The terpolymerization of the three monomers (3-vinyl phenylazo)methylmalodinitrile (1), (3-vinyl phenylazo)phenylsulfid (2) or 1-(3-vinylphenylazo)-1,1′-diphenyl methylacetate (3) with methyl methacrylate and butanediol-1,4-dimethyacrylate leads to networks in which the thermolabile azo groups remain intact. Both, the azo monomer and the crosslinking agent are essentially quantitatively incorporated into the network before the conversion of the third monomer is complete. The networks have been characterized in terms of their swelling in benzene, chlorobenzene, and methacrylonitrile. Die Terpolymerisation der drei Monomeren (3-Vinylphenylazo)-methylmalodinitril (1), (3-Vinylphenylazo)phenyls…

Compatibility between polystyrene copolymers and polymers in solution via hydrogen bonding

2006

Abstract It has been applied the concept of improving miscibility, by introducing and optimizing the extent of intermolecular hydrogen-bonding interactions between two polymers. We select a commodity polymer such as polystyrene, to study the compatibility in chloroform with poly(vinyl pyridine) and poly(vinyl pyrrolidone), both considered as proton acceptors. In order to enhance polymer–polymer miscibility, polystyrene is slightly modified by copolymerization with methacrylic acid, in the first case, and with vinyl-phenol comonomer, in the second one. In this way, two series of polystyrene-based copolymers are synthesized and characterized bearing ca. 8% (w/w) of –OH groups. The miscibility…