Synthesis and Thermal Conversions of Unsaturated Nickel(II) Dicarboxylates as Precursors of Metallopolymer Nanocomposites

Nickel(II) dicarboxylates of unsaturated carboxylic acids (maleic (MalA), itaconic (ItA), acetylenedicarboxylic (ADCA), allylmalonic (AlMalA), glutaconic (GlutA), cis,cis-muconic (MucA) acids) were synthesized and characterized by thermal analysis and IR spectroscopy. The synthesized dicarboxylates were subjected to thermolysis, and the obtained nanocomposites were studied by transmission and scanning electron microscopy and X-ray diffraction. The synthesized metallopolymer nanocomposites were NiO and metallic Ni nanoparticles distributed over a stabilizing matrix. The formation enthalpy of dicarboxylates (Delta H-r degrees) was calculated by the PM3 semi-empirical quantum-chemical method. The nanoparticle size was determined, and a relationship between the average nanoparticle diameter (d(avg)) and Delta H-r degrees was established. The microstructure and magnetic characteristics of the obtained nanocomposites, namely, the maximum and residual magnetization and the coercive force, were studied.