Homopolymerization of thionolactone. The last point to investigate concerning the development of a new monomer for radical ring-opening polymerization concerns its ability to homopolymerize. CKAs and in particular 2-methylene dioxepane (MDO) are known to readily homopolymerize to obtain polyesters. There is only few data concerning the homopolymerization of thionolactones. Roth et al. reported the difficult homopolymerization of DOT with less than 10% conversion in 7 days at 60ºC. The same authors also reported the AIBNinitiated free-radical polymerization of DBT that reached 35% conversion after heating at 70 °C overnight. The polymer was characterized by NMR but not by SEC due to solubility issues. The homopolymerization of TIC was also reported but similarly to DOT, the polymerization proceeded slowly with 75% conversion reached after eight days at 70 °C in DMF. In addition, the produced polythioester has a low Mn (2,000-7,500 g.mol -1