Features of Polymerization of Methyl Methacrylate using a Photocatalyst—the Complex Oxide RbTe 1.5 W 0.5 O 6

Radical polymerization of methyl methacrylate in an aqueous emulsion was carried out using the complex oxide RbTe 1.5 W 0.5 O 6 as a photoinitiator under visible light irradiation with λ = 400–700 nm. Study of the polymerization process and reaction products using methods of physical and chemical analysis (GPC, IR, NMR, etc.) has shown that there are several directions of monomer transformations at the same time. Polymethyl methacrylate with Mn ~ 140–145 kDa, produced in the organic phase, is a result of polymerization initiation by a hydroxyl radical formed due to complex transformations of electron–hole pairs during photocatalyst irradiation. Moreover, the interaction of the hydroxyl radical with OH-groups on the complex oxide RbTe 1.5 W 0.5 O 6 surface and the subsequent formation of oxygen-centered radicals lead to grafting polymer macromolecules on the photocatalyst surface. In addition, methyl methacrylate is able to oxidize to a cyclic dimer with terminal double bonds and form a polymer with cyclic dimer links due to coordination by double bonds on the RbTe 1.5 W 0.5 O 6 surface. The high activity of the hydroxyl radical allows to obtain the graft copolymer PMMA-pectin by grafting the polymer product on the surface of the natural polymer-pectin. Comparison of the sponge morphology of the graft copolymer PMMA-pectin and the initial pectin samples using the scanning electron microscopy has shown a noticeable difference in their structural and topological organization. It is especially interesting in terms of studying the properties of the graft copolymer as a material for the scaffolds.