Synthesis of methacrylate polyanion chains via RAFT polymerization, kinetic study. Thermal properties of its copolymers with MMA and monomers’ reactivity ratios

Polyanionic chains, in which multiple monomeric units bear anion groups as counter ions to Li⁺, are excellent candidates for the preparation of polymer-based electrolytes, where anion movement is restricted, while lithium ions are free to move in the polymer matrix The aforementioned, are characterized as single Li-ion polymer electrolytes, and a great research effort is currently focused on the controlled synthesis and molecular characterization of such materials. Herein, we report the synthesis of Potassium 3-sulfonyl (trifluoromethane sulfonyl) imide propyl methacrylate (MASTFSIK) ionic monomer and its controlled polymerization kinetics, using RAFT techniques, while the progression of polymer tacticity is also noted in relation to the molecular weight of the growing polyanionic chains. The ion – exchange reaction with LiClO₄ can be used to obtain the lithiated analog (PMASTFSILi). A series of linear copolymers (PMMA-co-PMASTFSILi) was synthesized with comparable degree of polymerization and varying compositions, considering the different monomeric units, for their thermal properties to be evaluated. The data suggest the presence of strong ionic interactions within the polymer matrix, resulting in a significant increase of the glass transition temperature for the polyanionic samples. The reactivity ratios of the MMA, MASTFSIK monomers were studied with various methods (FR, inv FR, KT, COPOINT), showing a preferential propagation of the MASTFIK monomer at low monomer consumption.