Electroinitiated Polymerization Research Articles

Electroinitiated polymerization of maleic anhydride

AbstractThe electroinitiated polymerization of maleic anhydride was studied in N,N‐dimethylformamide medium using sodium acetate (saturated solution) as the electrolyte. A dark brown polymer is formed only after the passage of an electrical current. Its yield increases in the presence of the electrolyte and depends on several factors such as the magnitude of the current flow, the duration of the electrolysis, the temperature of the cell solution and the monomer concentration. Split‐cell experiments showed that the polymer is formed in the anode compartment from a red coloured precursor, which is generated in the cathode compartment, but subsequently migrates to the anode compartment. The IR spectrum suggests that the polymer is mainly a cis‐poly(vinyleneketoanhydride), containing also other moieties in the chain such as cyclopentanone and maleic anhydride.

Electroinitiated cationic polymerization of isoprene

Electroinitiated cationic polymerization of isoprene

On the electro-initiated polymerization of β- N-carbazolyl ethyl vinyl ether

β- N-carbazolyl ethyl vinyl ether, a monomer having the carbazolyl substituent at a distance from the vinyl group, was submitted to electro-initiated polymerization. Polymers with η red = 0.015–0.07 dl g −1 were obtained in the anodic compartment of a two compartment cell. The i.r., NMR and u.v. spectra show structural characteristics similar to those obtained by conventional cationic polymerization of the monomer but also some peculiarities associated with the conditions of electrochemical synthesis.

Electroinitiated polymerization of p‐diethynylbenzene

AbstractThe electroinitiated anionic polymerization of p‐diethynylbenzene was carried out in various solvents with different solvation capacity using various electrolytes. The latter were classified depending on their efficiency for the polymerization which was found to be in good agreement with polarographic measurements. IR and H NMR spectral analyses of the polymers obtained showed the formation of extended π‐conjugated systems with only one of the two acetylenic bonds having reacted, thus giving soluble products suitable for structural studies.

Reactivity of some acetylenic derivatives in electroinitiated polymerization

The charge distribution in phenylacetylene, methyl propiolate, diphenyldiacetylene as well as in their anion-radieals was calculated by GNDO/2 and EHT methods. According to the obtained results, the electroinitiated polymerization of these monomers takes place by their direct reduction. A good agreement between theoretical and electroanalytical data was observed.

Electroinitiated polymerization of N-vinylcarbazole in mixed biphasic media

Milieu forme d'une phase polaire (formamide plus electrolyte) et d'une phase non polaire (solution du monomere dans un liquide non polaire comme le toluene)

Electroinitiated polymerization of 2-ethylhexylacrylate on carbon fibers

The electroinitiated polymerization of 2-ethylhexylacrylate in dimethylformamide in the presence of tetrabutylammoniumiodide was investigated at 288–314 K, with graphitized monofibers being used as a cathode. Electron microscopy showed that the surface of a carbon fiber is characterized by considerable microheterogeneity. The fiber interaction with the propagating polymer chain was supposed to be different due to the energetic microheterogeneity of the fiber surface. This has been proved by micrographs of carbon fiber samples after electrolysis. The local excrescences of poly (2-ethylhexylacrylate) could not be separated after prolonged acetone extraction of the samples. They were conventionally referred to as a grafted polymer. It is inferred that the energetic surface microheterogeneities have a considerable effect on the grafting process regardless of the nature of the reactive centers. The use of carbon monofibers as a cathode does not substantially affect the mechanism of the 2-ethylhexylacrylate electroinitiated bulk polymerization. It is shown that the solution polymerization of 2-ethylhexylacrylate in dimethylformamide occurs according to an anionic mechanism and leads to oligomer formation. The experimental rate constants of the electroinitiated polymerization of 2-ethylhexyl-acrylate, depending on current density and temperature, as well as the total activation energy were determined.

Electro-initiated cationic polymerization of α-methylstyrene by direct electron transfer

Electro-initiated cationic polymerization of α-methylstyrene in a tetrabutylammonium fluoroborate-dichloromethane system has been investigated at various temperatures by constant potential electrolysis. It is established that polymerization occurs at low temperatures with higher yields. Apparent activation energy of the electro-initiated polymerization is −64.3 kJ mol −1.

Electroinitiated and radiation‐induced polymerisation of epoxycyclopentane

AbstractLiquid state radiation‐induced and electroinitiated polymerisations of epoxycyclopentane (ECP) have been investigated. Dichloromethane and tetrabutylammonium hexafluoro‐phosphate were employed as a solvent electrolyte couple. Temperature effects on the rate of electroinitiation were also studied. Apparent activation energy for the electroinitiated polymerisation was calculated from the Arrhenius plot. The propagation of the polymerisation for both methods was found to be through the opening of the epoxy ring, as verified by i.r. and n.m.r. spectra. Both methods of polymerisation yielded tacky, amorphous polymers.

Electroinitiated Polymerization of Acrylamide Using Tartaric Acid as Electrolyte

Abstract Acrylamide has been polymerized electrochemically in aqueous medium in the presence of tartaric acid, and the effects of such reaction variables as monomer concentration, electrolyte concentration, and current on the rates of polymerization have been studied. The mechanisms of initiation and termination have been discussed in the light of the observed kinetic data. Initiation is believed to occur through the generation of radical ions during electrolysis, and electrolytic termination is found to be negligible during the polymerization process.

Electroinitiated and radiation-induced polymerisation of epoxycyclohexane

Liquid-state radiation-induced and electroinitiated polymerisations of epoxycyclohexane (ECH) have been investigated. The effect of temperature on the electroinitiated polymerisation rate was also studied. The decrease in monomer concentration during polymerisation was followed by gas chromatographic analysis of electrolysis solutions. The i.r. spectra of the polymers suggested polyether structure. N.m.r. spectra of products indicate that the polymerisation of ECH propagates through the opening of the epoxy rings. Poly(epoxycyclohexane) obtained by both methods are amorphous according to X-ray analyses.

Radiation-induced and electroinitiated polymerisation of 1, 2-Epoxy-4-epoxyethylcyclohexane

Liquid state radiation-induced and electroinitiated cationic polymerisation of 1,2-epoxy-4-epoxyethylcyclohexane (EECH) have been investigated. Soluble and cross-linked polymers were obtained during the radiation-induced polymerisation of EECH, depending upon the radiation dose. Electroinitiated polymerisation of the monomer yielded cross-linked polymers on the surface of the anode. The expected polyether structure was observed for i.r. data. The polymerisation propagates via opening of the epoxy rings as indicated by n.m.r. spectra. X-Ray analyses showed that the products obtained by both methods are amorphous.

Electroinitiated polymerization of some acetylenic derivatives, a polarographic study

AbstractThe polarographic reduction of some acetylenic derivatives—phenylacetylene, diphenyldiacetylene and methyl propiolate, as well as of some quarternary salts (ammonium, phosphonium, arsonium and stibonium), was investigated in order to establish whether the electroinitiated polymerization process took place by direct electron transfer to the acetylenic monomer or indirectly.The half‐wave potentials of the compounds mentioned at the dropping mercury cathode and at the stationary platinum electrode were measured. From the experimental data on the polymerization of the above acetylenic monomers, some statements on the kinetics of the polymerization process were made.

Electroinitiated cationic polymerization of some epoxides by direct electron transfer

Electroinitiated cationic polymerization of some epoxides by direct electron transfer

On the electroinitiated polymerization of some acetylenic derivatives

AbstractPhenylacetylene, diphenyldiacetylene and methyl propiolate were polymerized by electrochemical initiation in aprotic, polar solvents (dimethylformamide, dimethylacetamide and acetonitrile) using ammonium, phosphonium, arsonium and stibonium quaternary salts (alkyl‐, aryl‐ and alkyl‐aryl‐substituted) as background electrolytes. The effect of electrolyte nature and concentration, of the solvents and of electrolysis conditions on the product yields were studied as well as some properties of the obtained polymers.

Electroinitiated polymerization of methyl methacrylate in two phase media

The electroinitiated polymerization of methyl methacrylate has been carried out in an intimately mixed two phase medium consisting of a polar solvent containing some added electrolytes and a non-polar phase containing the monomer. Formamide has been used as the solvent for the polar phase and methyl methacrylate either alone or in solution in benzene or toluene has been used as the non-polar phase. Ferric salts are found to catalyse the electropolymerization process; using ferric sulphate as the electrolyte, polymers having molecular weights in the range, 1–2×106 have been obtained, with the highestR p of 7.3% per hour and the highest polymerization efficiency of 30.37 mol F−1. A radical mechanism is suggested for the process based on the experimental results.

Electropolymerisation of methyl methacrylate on carbon fibre surfaces

The electroinitiated polymerisation of methyl methacrylate containing sulphuric acid was found to be localised at the surface of a cathode of carbon fibre. The influences of various reaction parameters on the rate of polymerisation and the molecular weight have been recorded but do not agree totally with classical free radical electropolymerisations. The behaviour of molecular weight and evidence of post-polymerisation suggest the existence of living polymer radicals. It is argued that atomic hydrogen is responsible for initiation of the polymerisation.

Electroinitiated polymerizations of indene and acenaphthylene

Electroinitiated polymerizations of indene and acenaphthylene

Electroinitiated cationic polymerization of styrene in the presence of ferric chloride

The electroinitiated polymerization of styrene has been studied in acetone with ferric chloride as the electrolyte. At a fixed monomer concentration, the polymer yield depends on the current strength as well as the concentration of ferric chloride. The molecular weight of the polymer lies in the range of 1000–3000. Addition of zinc chloride to the system or replacement of the solvent by DMF (partly or fully) or methanol retards the polymerization. The current exponent of polymerization is unity with a reaction rate constant of 4.416 × 10 −2 reaction percent per hour. The locus of polymerization is the anode compartment. A cationic mechanism has been proposed for the polymerization, the initiating step consisting of an electron transfer from an adsorbed charge transfer complex of styrene and ferric chloride.

Electroinitiated polymerization of butyl isocyanate: 2. Polymerization kinetics

Electrolysis of a solution of a quaternary ammonium perchlorate or tetrafluoroborate produces a transient species capable of polymerizating n-butyl isocyanate: some direct reduction of the monomer also occurs. High molecular weight polymer is produced during the early stages of the reaction, and small but measurable quantities of cyclic trimer are formed during the later stages. Kinetic analysis of the polymerization indicates a complex reaction mechanism; above a certain current density the overall rate of reaction appears to be zero order in current. The rate also shows an unusual acceleration and appears to depend on the quantity of monomer already consumed.