Synthesis and characterization of functionalized vinyl copolymers. Electronegativity and comonomer reactivity in radical copolymerization

Vinylsilane monomers (vinyltrimethoxysilane (VTMOS) and vinyltriethoxysilane (VTEOS)), methyl methacrylate (MMA), tert-butyl acrylate (tBA) and N-vinyl-2-pyrrolidone (VP) were used in the synthesis of functionalized vinyl copolymers. By using these monomers, VTMOS-co-MMA, tBA-co-VP and VTEOS-co-VP, with various compositions, were synthesized. The copolymers were characterized by viscometry, ¹H-NMR, FTIR and elemental analysis. The monomer reactivity ratios were estimated by the Fineman-Ross and Kelen-Tüdōs linear procedures. These parameters were also estimated by using a computer program based on a non-linear minimization procedure known as Reactivity Ratios Error in Variables Model. Random copolymers and others containing blocks of one of the monomer units were obtained, depending on the chemical nature of the comonomers. The estimated comonomer sequence and distribution are discussed in terms of structural properties of the monomers such as molecular volume of the side groups, electronegativity of the substituents and steric hindrance. Analysis by comparison with other copolymers with analogous structures was also performed.