Polymerization Of Polar Vinyl Monomers Research Articles

Effect of tertiary diamines on anionic polymerization of polar vinyl monomers

AbstractTertiary diamines that exhibit chelating capability to lithium are shown to decrease the reactivity of growing species when used in classical anionic polymerization of methacrylic monomers. Out of the different diamines investigated, sparteine turns out to be the most efficient chelating agent. The beneficial effect of the latter additives on the overall reactivity of methacrylic anions was exploited to prepare poly(MMA) samples of controlled size at room temperature. The decrease in reactivity was also demonstrated from a kinetic point of view, upon measuring the actual rate constant of propagation using vinyl pyridine as model monomer.

Tailoring of polyacrylates with combined initiators

AbstractThis article summarizes possibilities of tailoring polyacrylates and polymethacrylates prepared by anionic polymerization initiated with combined (mixed) initiators especially those containing alkali metal tert‐alkoxides as stabilizing additives. First part gives a short overview of side reactions in anionic polymerization of polar vinyl monomers and the ways of solving the problem. Second part is devoted to the anionic polymerization of acrylic and methacrylic esters initiated with mixed initiators. Examples of synthetic methods are given for the preparation of special polymeric products based on acrylates, and the necessity of using different polymerization conditions for individual acrylic esters is demonstrated with respect to branching of the ester alkyl group.

Solvation effects in anionic polymerization of polar vinyl monomers

AbstractThe anionic polymerization (AP) of polar vinyl monomers (PVM) is strongly affected by additives with electron donor and electron acceptor properties. For the purpose of estimating the interactions of the active centers (AC) of chain growth with different ligands, the approach of studying a reference system was adopted, viz. lithium picrate (LiPi) in dioxane (DO). Three types of interaction were distinguished: with electron pair donors (EPD), with Li salts and alkoxides, and with Lewis acids. Spectral evidence was found of charge transfer complexation with Li alkoxides and enolates, leading to modified dianionic Meisenheimer adducts. The experimental procedure was employed in studies of competitive solvation of LiPi by two ligands. The results were related to reviewed literature data on the kinetics and stereochemistry of methyl methacrylate (MMA) and 2‐vinylpyridine (2VP) polymerizations by lithium initiators.

The effect of complexing agents on the radical polymerization of polar vinyl monomers

AbstractRadical polymerizations of acrylonitrile, methacrylonitrile, methyl acrylate, and methyl methacrylate in the presence of Lewis acid type complexing agents like ZnCl2, SnCl4, or (C2H5)nAlCl3−n (n = 1,2,3) were investigated. The accelerating or inhibiting effects of the complexing agents on the polymerization of individual monomers were observed depending on the concentration and the character of the complexing agent. These effects were found to be also influenced by the monomer structure. The polymerization mechanism is discussed.