Preparation and reactivity of metal-containing monomers. 21. Spontaneous polymerization of acrylamide coordinated to metal nitrates

Acrylamide coordinated to Cr(III), Bi(III), Pb(II), and Ca(II) nitrates polymerizes spontaneously in concentrated aqueous solutions at 20°C with formation of glass-like polymers containing water. The process takes from several hours to several days, depending on reaction conditions and the nature of the metal nitrate. The product contains water-soluble and water-insoluble fractions. The insoluble fraction is polyacrylamide containing no metal compound. The possibility of spontaneous copolymerization of acrylamide complexes of metal nitrates with other water-soluble monomers was established.Institute of Energy Problems in Chemical Physics, Chernogolovka Branch, Russian Academy of Sciences, 142432 Chernogolovka. Institute of Chemical Physics, Chernogolovka Branch, Russian Academy of Sciences, 142432 Chernogolovka. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 2073–2080, September, 1992.     

Preparation, X-ray structure, copolymerization with styrene of [(μ-H)Os3(μ-OCNMe2)(CO)9{P(CH2CHCH2)Ph2}] and catalytic properties of the cluster/styrene copolymer

The complex [(μ-H)Os₃(μ-OCNMe₂)(CO)₉{P(CH₂CHCH₂)Ph₂}] derived from the replacement of a lightly-stabilizing NMe₃ ligand in [(μ-H)Os₃(μ-OCNMe₂)(CO)₉(NMe₃)] by allyldiphenylphosphine molecule was physico-chemically and X-ray structurally characterized and served further as a metal cluster monomer to be immobilized on a polymer surface. The copolymerization of this cluster monomer with styrene was studied. It was found that the cluster molecule, when copolymerized, maintains its integrity and the overall structure. The cluster copolymers obtained have been tested as catalysts for oxidative dehydrogenation and cyclohexenol hydroxylation reactions.     

Preparation and reactivity of metal-containing monomers

Polymethacryloylacetonates of some transition metals were obtained by free-radical polymerization of the corresponding metal-containing monomers and the main regularities of the process were studied. The complexation with a metal ion decreased the reactivity of the methacryloylacetone towards polymerization in the series Mn^II > Co^II > Ni^II > Cr^III, which is analogous to the electronegativity of these metals. Macrochelates thus obtained contain one equivalent of metal per monomer unit and their molecular weights are within 10000–18200. The structure of the coordination site was shown to be retained in the course of polymerization.For communication 34, see Ref. 1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2060–2064, December, 1993.     

Preparation and reactivity of metal-containing monomers

XPS and IR studies and elemental analysis of the polymerization product of Cu(II) acrylate suggest the partial reduction of Cu(II) during polymerization. A scheme of the polymer structure with metals of different valencies is suggested.For part 31 see Izv. Akad. Nauk, Ser. Khim., 1993, 1293 [Russ. Chem. Bull., 1993, 42, 1236 (Engl. Transl.)].Translated from Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1565–1568, September, 1993.     

Synthesis and reactivity of metal-containing monomers

The polymerization of diacrylates of the nontransition metals Mg, Zn, Ba, and Pb, which proceeds at low temperatures (5–10°C) with the complexes of alkylcobalts with tridentate Shiff bases (RCo) as initiators, was studied. The radical mechanism of the process was proved with the aid of free radical scavengers. The polymerization kinetics is given by the equationW _n = k [M] · [RCo]^0.75. The influence of the nature of the metal in the monomer and the alkyl ligand in the initiator on the polymerization process was discussed. Low temperatures promote the formation of polymers with high molecular weights and a predominantly syndiotactic structure. The effect of the steric hindrances arising during polymerization due to the formation of a three-dimensional cross-linked structure in the metal-containing polymer on the microstructure of polymer chain and on polymerization kinetics was considered.For part 24 seeBull. Acad. Sci., Div. Chem. Sci., 1992, 1609.For a preliminary communication see Ref.1.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 500–503, March, 1993.     

Polymer Sol-Gel Synthesis of Hybrid Nanocomposites

The current state and main problems of polymer sol-gel synthesis as a method of the preparation of hybrid polymer-inorganic nanocomposites are analyzed. The general characterization of sol-gel reactions is given and the routes of the combination of sol-gel synthesis with the polymerization of traditional monomers are considered. Particular attention is given to the formation of sol-gel precursors in the presence of organic polymers, including the formation of interpenetrating hybrid networks. The specificity of hybrid nanocomposites based on multicomponent ceramics is discussed. The sol-gel process is analyzed as a promising route for the preparation of bioceramics in the presence of templates.     

Photochemistry of cyclohexene oxide radical cations in freonic matrices at 77 K

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Some properties of filled polyvinyl chloride

The effect of TiO₂, SiO₂, and carbon fillers on rigid, partly plasticized PVC has been investigated. Interaction in the polymer-filler system improves certain important properties — hardness, stiffness, wear resistance, etc., — the effect of the fillers being highly specific.M. V. Lomonosov Odessa Technological Institute. Translated from Mekhanika Polimerov, No. 1, pp 124–126, January–February, 1970.