Plant-based non-activated olefins: a new class of renewable monomers for controlled radical polymerisation

In light of fossil fuel depletion and a general necessity for sustainable development, the synthesis of polymers from renewable resources is gaining more and more importance. Yet, industrially relevant radical polymerisations still struggle with the incorporation of renewable resources as the number of natural molecules containing suitable double bonds is limited. Herein, we present the sustainable synthesis of non-activated allylic and olefinic carbonate monomers from renewable resources in a solventless one-pot transesterification reaction. We subsequently confirm the first controlled radical copolymerisation of such challenging non-activated monomers with vinyl acetate, in which molecular weights above 10,000 g.mol-1 were reached. The controlled nature of the copolymerisations was verified by the low dispersities obtained and the linear increase in molecular weights with conversion. The so-prepared copolymers were purified using sustainable extractions by supercritical carbon dioxide (scCO2), which allowed to recover unused monomer in up to 58%. Using FT-IR and NMR spectroscopy, the incorporation of the renewable monomers into the copolymer in up to 49 mol% was confirmed, which is the highest reported to date. The combination of a sustainable double bond functionalisation pathway with controlled radical polymerisations highlights the potential of radical polymerisations in the quest for renewable polymers and introduces a new set of monomers for this technique.