Structuring elements of zirconium oxyhydrate gels under unbalanced conditions

Hydrated water in zirconium oxyhydrate gel is shown to be located in the inner region of the polymer compound in the gap between the molecules of zirconium oxide and to provide the bond between monomer units. For example, with the hydration of the compound (ZrO2(H2O)3)2·ZrO2(H2O)5, the water molecule cannot enter directly into the inner region; therefore, the hydration of such a chain is not energetically equivalent to the reaction of addition of the hexahydrated form to the dimer. Structural difficulties accompanying the hydration of trimers and other forms of oxyhydrated polymers require the restructurization of the polymer chain to transfer into a more stable state. Such a transformation includes the successive processes of destruction, hydration and further construction of the chain. The activation energy of the destruction process is comparable with the energy of hydrogen bonds; therefore, the destruction rate of the chain is rather high. Moreover, it is to increase with the increase in the number of units in the chain. The pentahydrate is the most stable molecular form in the system under consideration. Therefore, it is the interaction of the pentahydrate form of oxyhydrate with the polymer chain, which is the most probable. The interaction of the pentahydrate with the metastable trimer (ZrO2(H2O)3)2·ZrO2(H2O)5 results in the formation of the metastable tetramer with 16 water molecules, while the stable tetramer should contain 19 water molecules. The fact confirms the theoretical scheme of oxyhydrate gel polymerization reactions described in the literature and in the present work, since the splitting-off of water molecules as a result of the olation-polymerization reaction is accounted for by the formation of this kind of metastable products. The successive growth of chains and their discrete destruction provide the time periodicity of gel properties. The structural peculiarities of the polymer chain formation are of special interest. The location of monomer units in the most beneficial tetramer (ZrO2(H2O)3)2·ZrO2(H2O)6·ZrO2(H2O)7 resembles the origin of the helix coil growth. In this case, the molecules of bond water are in the center of the coil to form some chain providing the structure-formation.