Since then, Destarac and Harrisson, in parallel with our group, presented thionocaprolactone (thCL, Figure ) as an efficient thionolactone to copolymerize with vinyl acetate. We also started gaining better understanding of the DOT reactivity via a joined experimental/theoretical study. We showed that contrary to some data in the literature, the copolymerization with styrene at 80 °C is possible but with a lower reactivity of DOT compared to styrene. The reactivity of this couple of monomers could nevertheless be modified at higher temperature (150 °C) with the reactivity ratio of styrene (rS) and DOT (rDOT) measured at 0.55 and 1.68 respectively. We then succeeded to obtain a poly(S-co-DOT) with a high molecular weight (Mn = 75,000 g.mol -1 ) using 5 mol% of DOT at 150 °C in bulk. The copolymer presented similar mechanical and thermal properties than polystyrene but could be degraded into oligomers (Mn below 1,000 g.mol -1