Yu. I. Puzin

Radical polymerization of methyl methacrylate and styrene in the presence of ferrocene

Abstract The influence of ferrocene on the kinetic parameters of methyl methacrylate (MMA) or styrene polymerization is investigated. It is shown, that in the presence of ferrocene the growth of the initial rate of polymerization is accompanied with significant decrease of the polymerization degree of polymer obtained when peroxides are used as the polymerization initiators. The polymerization kinetics parameters are evaluated. Its demonstrated that the process of polymerization in the presence of a ferrocene has a low activation energy, that allows to carry out the polymerization at lower room temperatures. The influence of the ferrocene on the molecular-mass characteristics of poly(methyl methacrylate) (PMMA) was studied and it was found that the influence of ferrocene on PMMA molecular mass is determined by the nature of the initiator used. The decomposition temperature of PMMA increases with the increase of ferrocene concentration. Monte-Carlo technique was used for numerical simulation of MMA radical polymerization kinetics in the presence and in the absence of ferrocene and to follow the change of molecular-weight distribution during the polymerization. The peculiarities of polymer radical concentration changes at the initial stage of polymerization are shown. Satisfactory correspondence between calculated and experimental data was obtained.

Controlling the polymerization of methyl methacrylate with ternary initiating systems

The effect of ternary initiating systems benzoyl peroxide-ferrocene-3,6-bis(o-carboxybenzoyl)-N-isopropylcarbazole and benzoyl peroxide-di-η5-indenylzirconium dichloride-3,6-bis(o-carboxybenzoyl)-N-isopropylcarbazole on the radical polymerization of methyl methacrylate and on the heat resistance and microstructure of the resulting polymers was examined.

Polymerization of methyl methacrylate and styrene in presence of phthalides

Abstract The radical polymerization of vinyl monomers (methyl methacrylate, styrene) has been investigated in the presence of phthalides of different structure. It is shown that the phthalides containing halogen atoms are, first of all, chain-transfer agents. The values of chain-transfer constants to them have been determined. It was found that the presence of chlorine atom bounded directly with carbon of phthalide cycle in a phthalide molecule results in considerable growth of chain-transfer constant value to phthalide. If the halogen is connected with aromatic group of phthalide, phthalide is a weak chain-transfer agent and the phthalide cycle is not included in polymer molecule. It is shown that the phthalides containing mobile atoms of hydrogen can take part both in chain-transfer and in initiating system formation with the initiator. The function of phthalide is determined by structure of phthalide, monomer and initiator. The mechanism of phthalide participation in polymerization has been discussed. The solutions of poly-MMA containing phthalide groups in macromolecules in concentrated sulfuric acid are intensively colored. This fact was used for quantitative determination of phthalide cycles in a polymer chain. It has been found that when UV irradiated the bulks of poly-MMA fluoresce and phosphoresce in a visible part of spectrum.

Polymerization of vinyl monomers initiated by peroxide-geminal bis-sulphide systems

Abstract It is found that the interaction of geminal bis-sulphides with acyl(aroyl)peroxides forms systems which initiate polymerization in non-aqueous media. The mechanism of the reaction of benzoyl peroxide with bis(amylthio)methane was studied. The initiation is shown to result form the products of the interaction of the components.

Effect of a three-component initiation system ferrocene-zirconocene dichloride-benzoyl peroxide on the free-radical polymerization of methyl methacrylate

The free-radical polymerization of methyl methacrylate initiated by the three-component system ferrocene-zirconocene dichloride-benzoyl peroxide has been studied. The kinetic features of the process, the interaction between components of the initiation system, and the molecular characteristics of the polymers have been investigated. In the case of the three-component initiation system, the content of syndiotactic fragments grows and the thermal stability of the polymers is improved compared to the products of polymerization carried out in the presence of solely a peroxide initiator.

Effect of dicyclopentadiene-and diindenezirconocene dichlorides on free-radical polymerization of methyl methacrylate

The effect of zirconocene dichloride and its indene-containing derivative on the radical polymerization of methyl methacrylate initiated by benzoyl peroxide has been studied. The influence of the metallocenes on the kinetic parameters of the process and the average degree of polymerization has been established. Concentration and temperature dependences have been measured for the initial rate of reaction and the average degree of polymerization in relation to the content of the components in the systems. The microstructure of poly(methylmethacrylate) prepared in the presence of the used initiation systems has been determined.

Preparation of Phthalide-containing Methacrylates

Different unsaturated products of the synthesis of phthalide-containing methacrylates were obtained depending on the polarity of the reaction medium: In a donor solvent (pyridine) the phthalide ring is conserved in the product, in acetone or toluene its opening occurred.

A ternary initiating system for free-radical polymerization of methyl methacrylate

The effect of a benzoyl peroxide-ferrocene-3,6-bis(o-carboxybenzoyl)-N-isopropylcarbazole three-component initiating system on the free-radical polymerization of methyl methacrylate has been investigated. For this process, concentration and temperature dependences of the initial rate of reaction and the average degree of polymerization have been measured. It has been established that, when the process is carried out in the presence of both ferrocene and a carbazole derivative, the former compound predominantly affects the kinetic parameters and the average degree of polymerization. The effect of the nitrogen-containing compound comes into play as the temperature of polymerization is lowered. Poly(methyl methacrylate) prepared in the presence of the ternary system is distinguished by an increased content of syndiotactic units and by the presence of isotactic structures, thus suggesting the complex-radical mechanism of polymerization.

Quantitative Determination of Phthalides in Molecules of Vinyl Polymers and Their Role in Radical Polymerization

The applicability to vinyl polymers of the procedure for quantitative determination of phthalide groups in polymeric molecules from the color of their sulfuric acid solutions was examined. The correlation between the intensity of the color of sulfuric acid solutions of polymers (polymethyl methacrylate, polystyrene) and the content of phthalide fragments incorporated into the polymer molecule was studied systematically on a quantitative level.

Prolongation of curing of epoxy-novolac vinyl ester resin with transition metal acetylacetonates

The effect of transition metal (Fe, Cu, Co, Ni, Cr, Mn) acetylacetonates on curing of epoxy-novolac vinyl ester resin was studied. The resin gel time was determined by the method for monitoring gelation of liquids with increased viscosity, and the influence of the structure and concentration of metal acetylacetonates on the process was examined. Nickel acetylacetonate inhibits the curing, whereas cobalt acetylacetonate ensures relatively fast process completion and can be used as curing accelerator. Iron and chromium acetylacetonates prolong the process. The curing time can be regulated by varying the amount of the additive.