Anionic ring-opening polymerization of epsilon-thionocaprolactone

Anionic ring-opening polymerization of epsilon-thionocaprolactone was exami ned. When organolithiums, Grignard reagents, and Lithium tert-butoxide were used as the initiators, the corresponding polythiocarboxylic-O-ester was s electively formed. When potassium tert-butoxide and 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) were used, the corresponding polythiocarboxylic-S-ester w as predominantly formed. The monomer conversion and M-n of the obtained pol ymer increased with the polymerization temperature. Elongation of polymeriz ation time resulted in decrease of the polymer yield and M-n. The polymeriz ation in tetrahydrofuran (THF) proceeded faster compared with the polymeriz ation in toluene. Formation of a cyclic dimer was observed in the polymeriz ation in THF.