Metallopolymer hybrid nanocomposites: Preparation and structures

Abstract

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.