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 353–433K 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 (r ₁=0.63, r ₂=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.