The thesis is devoted to the development of scientific and practical principles of the modification of vinyl polymers based on styrene and methyl methacrylate with unsaturated metal beta-diketonates, by their chemical immobilization on polymer matrices. The laws of the implementation of two methods for the synthesis of mono- and heterometallic -diketonate-containing polymers were studied, namely radical copolymerization of unsaturated beta-diketonates of transition metals with vinyl monomers and complex formation of metal salts with beta-diketones previously immobilized on polymer matrices.
Using unsaturated transition metal beta-diketonates in the radical polymerization of vinyl monomers, their multifunctional action as initiators, comonomers and inhibitors was established. These functions can be controlled using various concentrations, temperatures and donor additives. The presence of such an effect ensures the introduction of chelates into the polymer chain and causes the kinetics of radical polymerization to deviate from the classical dependences: the process rates have a nonlinear dependence on the concentration of beta-diketonate, the orders of reaction for the chelate are less than 0,5, and the molecular masses increase proportionally with increasing polymerization rate. Depending on the nature of the metal, for each metal complex there is a certain boundary concentration, upon reaching which, inhibition begins to prevail over initiation, resulting in inhibition of the process. This fact limits the comonomer function of unsaturated beta-diketonates and leads to the introduction of metal into the polymer in amounts of less than 1%. It was established that the inhibitory effect can be reduced by increasing the temperature, using donor solvents and an additional initiator – benzoyl peroxide.
Modification of polystyrenes (PS) and polymethyl methacrylates (PMMA) by complexation of metal salts with copolymer beta-diketones as macromolecular ligands leads to the production of beta-diketonate-containing polymers with a metal content of up to 2%. At the same time, factors affecting the number of chelate groups in the polymer are: the nature of the solvent, matrix, acidosols and their concentration. It was found that the most effective chelation occurs with the participation of the 1,4-dioxane - metal acetate system. In the case of using conjugated beta-diketones for obtaining a macromolecular ligand, it is necessary to use a compensation copolymerization method to more evenly distribute chelating groups in the chain, while the volume ratio of vinyl beta-diketone: vinyl monomer should not be large (1:30). In this case, macromolecular chelates are formed according to the intramolecular type; with an increase in the amount of the beta-diketone component, polymeric beta-diketonates of divalent metals have an intermolecular type structure, and the proportion of mixed-ligand complexes in the reaction products increases. For more effective regulation of the amount of metals, a fundamentally new method for the synthesis of bimetallic polymer beta-diketonates has been developed, which is a combination of copolymerization and complexation methods.
