Controlled Pyrolysis of Metal‐Containing Precursors as a Way for Synthesis of Metallopolymer Nanocomposites

Abstract

The processes of thermal decomposition play an important role in various practical fields including metallurgy, mineral conversion processes, pyrogenic chemical technology, pyrolysis and thermal treatment of wood and coal, combustion of natural and synthetical fuels, coal carbonization, the prevention of grain spontaneous ignition, and so on. There is still a need for scientifically well-founded approaches to control the thermal decomposition of materials. Many studies focus attention on the chemical transformations and reactions in the pyrolized systems and on the creation of mathematical models of such processes as the major parts of the theory of chemical decomposition of complex substances.Thermolysis is widely used in the synthesis of nano-sized metallopolymer composites. This is a result of the specifics of the preparation of such materials. In spite of a variety of the methods for the preparation of metallopolymer nanocomposites, there are two principal routes: "bottom-up" and "top-down."

Decoration of cellulose nanocrystals with iron oxide nanoparticles

“…CNCs were decorated with IONPs by the in situ thermal decomposition of iron pentacarbonyl, Fe(CO) 5 [38][39][40][41]. As a first step, 10 ml of a freshly-prepared CNC suspension was mixed with 10 ml DMF and sonicated (Qsonica, Q125) for 10 min (2 min for 5 cycles) to obtain a uniform dispersion.…”

“…In the presence of DMF, Fe(CO) 5 undergoes a disproportionation reaction resulting in the formation of Fe(II) moieties having six coordinated DMF molecules [40][41][42], as shown in figure 2. Variable amounts of CO gas are eliminated during the reaction, depending on the molar ratios of the Fe(CO) 5 and DMF compounds.…”

Decoration of Cellulose Nanowhiskers with Iron Oxide Nanoparticles

“…In the presence of DMF, Fe(CO)5 undergoes a disproportionation reaction resulting in the formation of Fe(II) moieties having six coordinated DMF molecules [32][33][34], as shown in The subsequent thermal decomposition of the iron carbonyl/DMF complexes on the surface of the CNWs results in the in-situ generation of iron nanoparticles on the surface of CNWs through the removal of the CO groups, followed by the oxidation of the iron moieties to Fe3O4 or γ−Fe2O3. The process may be catalyzed by the presence of the sulfonic groups, which may also be involved in the decomposition of the iron carbonyl complexes during the process [35].…”

Hafnium-containing Nanocomposites

“…The most convenient approach to producing hafniumcontaining nanocomposites with the aim of optimizing the formation of refractory hafnium oxide or carbide nanoparticles is controlled thermolysis of polymers 1-12. Note that polymer-mediated synthesis is an effective means of producing nanoparticles without aggregation during thermolysis, in contrast to other processes [22]. Thermodynamic analysis results for the Hf-C-H-O system lead one to the following conclusions: In the absence of hydrogen (system Hf-C-O), the solid phases existing in the range 0-3000 C at an Hf : C : O atomic ratio of 1 : 3 : 2 are HfC, HfO 2 , and C, and the gas phase consists of CO. Below 1700 C, the solid phases present are HfO 2 and C; above 1700 C, the phase composition is HfC (s) þ CO, which corresponds to the overall reaction HfO 2 (s) þ 3C (s) ¼ HfC (s) þ 2CO.…”