Polymerization Of Metal-containing Monomers Research Articles

Metallopolymer hybrid nanocomposites: Preparation and structures

Several approaches for producing metallopolymer hybrid nanocomposites were developed and analyzed. Among of them one-stage synthesis of metal nanoparticles and stabilizing polymer matrix – conjugated thermal (co)polymerization of metal-containing monomers and following thermolysis of forming polymers; in situ reduction of metal ions either in epoxy resins by curing agents or in thermoplastics by thermal decomposition of metal-containing precursor; and post synthetic modification of coordination polymers are considered. Thermal transformations of metal-containing monomers possess the unique way for preparation of nanocomposite materials when metal (or their oxides and carbides) nanoparticles and a stabilizing polymer matrix are formed simultaneously in situ. Molecular and supramolecular organization of nanocomposites obtained can be controlled during the thermal transformation of such monomers in inert or self-generated atmosphere. The main advantage of the synthesis of composites by thermal transformation of metal-containing precursors is in the possibility of formation of nanocomposites with a relatively high concentration of metal phase. Another advantage deals with technological simplicity and the ease to control the processes and the properties of material obtained. The process includes three stages: dehydration, solid-phase polymerization, and pyrolysis of the polymer products formed. The approach makes it possible to adjust the mean particle size in a given range by just choosing the appropriate reaction conditions. The composition of metal nanoparticles, their size and distribution on the size as well as the type and thickness of polymer shell can be controlled on the stage of nanocomposite formation. The nanocomposites obtained reveal ferromagnetic behavior at room temperature with high coercive force and magnetic anisotropy. With aim to control the composition and structure (for example, core–shell type) of ferromagnetic nanomaterials obtained as well as their properties, the reaction conditions such as temperature, ratio of starting compounds, the type of polymer matrix can be varied.

Polymers based on unsaturated alkoxides of refractory metals

Metallopolymers based on unsaturated alkoxides of refractory metals (Ti(IV), V(V), Ta(V), Nb(V)) are synthesized and characterized; their thermal behavior is studied via TGA, TMA, and DSC. It is shown that nanocomposite materials can be synthesized through the polymerization of metal-containing monomers and subsequent controlled thermolysis of the products.

Reactivity of metal-containing monomers 71. Synthesis of nanosized quasicrystals and related metallopolymer composites

The methods for the preparation of quasicrystalline intermetallic compounds in the protective matrix in the systems Al65Cu22Fe13 and Al54Cu9Mg37 were developed. They are formed both earlier and from elements during the formation of a metallopolymer composite material. Three methods of preparation are optimal: from low-dimensional powders of quasicrystals and film-forming polymers, by the in situ formation of quasicrystals during the thermal decomposition of the corresponding precursors, and via the thermal polymerization of metal-containing monomers (components of quasicrystals) followed by the controlled pyrolysis of the metallopolymers that formed. The metallopolymer composite obtained by the incorporation of Al63Cu22Fe13 into the high-density polyethylene or polyacrylamide matrix affords up to 10 wt.% cubic phase of β-Al50(Cu,Fe)50. The products of thermal decomposition of the low-molecular-weight precursors are a mixture of the quasicrystalline (Al65Cu22Fe13) and crystalline (cubic β-Al50(Cu,Fe)50 and tetragonal ω-Al7Cu2Fe, Al2Cu) phases. The thermolysis of the metallo-polymer composition yields a finely dispersed powder, whose main component is an alloy Al7Cu3Mg6 with an admixture of the Al2CuMg phase.

Reactivity of metal-containing monomers 66. Hydrogenation of nitrotoluene derivatives in the presence of polymer-immobilized Pd nanoparticles

A new approach to the synthesis of immobilized catalysts of the mixed type was developed: frontal polymerization of metal-containing monomers in the presence of a highly dispersed inorganic support. The synthesis of the acrylamide complex of PdII nitrate on the SiO2 surface followed by polymerization and reduction results in the formation of a polymer-inorganic composite with inclusions of Pd nanoparticles stabilized by the polymer matrix on the support surface. The study of the catalytic properties in the hydrogenation of nitrotoluene derivatives showed that the polymer-immobilized Pd nanoparticles on the inorganic support are efficient catalysts for the reduction of the nitrocompounds.

Frontal Polymerization of Metal-Containing Monomers: A Topical Review

The peculiarities of the frontal polymerization of metal-containing monomers containing acrylamide (AAm) complexes of transition metal nitrates, M(AAm) x (H2O) y (NO3)2 (M=Co, Ni, Fe, Cu, Zn, Cd, Ba), that are thermally initiated at 353–433 K are considered. It was found that nitrogen oxides (e.g., NO2, NO, N2O), which were formed by partial oxidation of the nitrate groups, were able to initiate the polymerization reaction. The reaction front and a self-sustained thermal wave were determined by structural-chemical and energy factors. The application of a self-propagating frontal polymerization to synthesize metal-containing copolymers was demonstrated. The constants of reactivity of the monomers (r1=0.63, r2=0.70) confirmed the statistical character of the copolymers obtained. Frontal polymerization of the AAm complexes that were filled by silica or glass powder was studied. Adding fillers stabilized the front and resulted in spatially uniform products. By following the controlled thermolysis of the metallopolymer or the controlled change of frontal polymerization into the burning regime lead to the formation of metallopolymer nanocomposites. The products were metal (or metal oxides) nano-scale particles that were stabilized by the polymer matrix that is formed.

Preparation and reactivity of metal-containing monomers. 9. Low-temperature postradiation polymerization of metalcontaining monomers in devitrification of the matrices

1. The features of phase transitions of metal-containing monomers (MCM) of Ni(II), Co(II), Cu(II), Cr(III), and Mn(II) acrylates and acrylamide complexes and Ti(IV) alkoxy derivatives were investigated in the region of low temperatures in bulk and in 10% ethanol solution. 2. The possibility of postradiation polymerization of MCM in devitrification in the matrix and alcohol solutions was demonstrated. 3. Postpolymerization of MCM in devitrification takes place less efficiently than postpolymerization of their analogs containing no metal atoms.

Preparation and reactivity of metal-containing monomers. Communication 6. Polymerization of metal-containing monomers based on alkoxy derivatives of Ti(IV) and some properties of the products obtained

1. Polymerization of Ti(IV) monomers in benzene is characterized by a reaction order of 0.5 with respect to the monomer, which is due to coordination of the radicals formed with the monomer and their predominant participation in chain breaking reactions. 2. The metal-containing polymers based on Ti(IV) have elevated thermal stability due to the formation of rare cross links between the macromolecules.