PREPARATION AND REACTIVITY OF METAL-CONTAINING MONOMERS .41. THE FORMATION AND THERMAL TRANSFORMATIONS OF NANOMETER-SIZED PARTICLES OF COBALT FERRITE UPON THE DECOMPOSITION OF COPRECIPITATED FE-III AND CO-II ACRYLATES

Thermal transformations (at 340 to 390 degrees C) of coprecipitates of iron and cobalt acrylates, [Fe3(O)(CH2CHCOO)(6)OH][Co(CH2CHCOO)(2)](2,4) (1) and [Fe3O(CH2CHOO)(6)OH][Co(CH2CHCOO)(2)](1.5). 3H(2)O (2), are studied. The dependence of the degree of gas evolution (eta) on time is described by the equation eta(t) = eta(l infinity)[1-exp(-k(1) tau)] + (1-eta(l infinity))[1-exp(-k(2) tau)], where k(1) = 2.3 . 10(12). exp[-49500/(RT)] s(-1), k(2) = 6.0 . 10(6) . exp[-33000/(RT)]s(-1) and k(1) = 2.6 . 10(12). exp[-49000/(RT)]s(-1), k(2) = 6.6 . 10(5) . exp[-30000/(RT)]s(-1) for cocrystallizates 1 and 2, respectively. The coefficient eta(l infinity) for compound 1 is higher than that for compound 2. The composition of products of the transformations of 1 and 2 are studied. The main solid state products of the decomposition are nanometer-sized particles of cobalt ferrite, CoFe2O4, with a narrow size distribution stabilized by the polymeric matrix. The thermal transformations of cocrystallizates 1 and 2 include dehydration, thermal decomposition, copolymerization in the solid state, and decarboxylation of the metallocarboxylate groups of the polymer. The effect of the ratio between the Fe clusters and the Co-containing fragments on the process of thermal transformation is analyzed.