Kinetic Features of Photoinduced Radical (Co)Polymerization of Ionic Monomers

A number of methacrylate ionic monomers with different ionic center nature, spacer structure, and position of the polymerizing group (in anion or cation) are synthesized. The kinetics of their photoinitiated radical (co)polymerization is studied by the thermographic method. Effects of the structure of ionic monomer, its ratio with the crosslinking agent poly(ethylene glycol dimethacrylate) (PEGDM-750) in the photopolymerizing composition, and the nature of the reaction medium on the kinetic parameters of the process, namely, the maximum rate Wmax, the degree of conversion Г, and the time of induction period tind, are investigated. It is shown that, among the studied methacrylic monomers, anionic monomer N-butyl-N-methylpyrrolidinium 1-[3-(methacryloyloxy)propylsulfonyl] (trifluoromethanesulfonyl)imide (ILM-5) exhibits the highest reactivity in both bulk and solution (in ionic medium) photopolymerization: Wmax = 69 × 10–3 s–1 and Г = 85% and Wmax = 60 × 10–3 s–1 and Г = 90%, respectively. For most cationic monomers, better results in homopolymerization are achieved in dimethylformamide. The kinetic features of the radical copolymerization of the ionic monomers with PEGDM-750 are studied. It is shown that, with a growing fraction of the crosslinking agent in the monomer mixture, Wmax and Г increase regardless of whether the process occurs in bulk or solution.