LAUSR

Abstract Ring-opening polymerization of cyclic dithiocarbonates was attempted by varying reaction conditions (temperature, concentration, and solvents) to achieve a high polymer conversion. The participation of neighboring sulfide groups in the ring opening was demonstrated by selective sulfide migration and evaluated by composition analysis of the resulting copolymer. The migration was accelerated by electron-enriching substituents on the aryl sulfide and led to the formation of homopolymers with alkyl sulfides. The isomerization of the monomer encountered in the polymerization reduced with sulfide migration and exclusively occurred as substituted by a trityl sulfide. Three catalytic isomerization pathways were proposed for the polymerization mechanism, wherein the electronic and steric contributions of a substituted sulfide group were considered to rationalize the competitive formation of polymers and isomers. The polymerization of a monomer carrying two neighboring groups of butyl sulfide and benzoate proceeded to homopolymerization involving the migration of a sulfide group. The preferential migration was confirmed by the isolation of a six-membered cyclic carbonate as the main fragment product of depolymerization that occurred in the presence of potassium tert-butoxide. A reactive chain end in living polymerization was modified by an in situ reaction with sodium dithiocarbamate. A linear correlation between experimental and theoretical number average molecular weights of the prepared polymers was investigated with polymer conversion variance. The neutralized chain-end improved the chemical stability of the prepared poly(dithiocarbonate)s, and a stable polydispersity was obtained. The thermal decomposition temperature, Td (10% loss), of a polydithiocabonate was measured at 189 °C and the corresponding value after end-capping of the polymer was 285 °C.