Dimères d’acides résiniques et de dérivés de la lignine : nouveaux précurseurs pour la synthèse de polymères bio-sourcés

摘要

The aim of this thesis is to investigate new biobased rigid synthons for the synthesis of polymers with high thermomechanical properties. A polycyclic biobased molecule, i.e resinic acids, and phenolic compounds potentially derived from lignin, such as vanillin were selected. Both classes of substrates were dimerized in order to get difunctional symmetric synthons. On the one hand, abietic acid dimers synthesized via a cationic mechanism presented an ill-defined structure. To avoid reactivity issues, dimers with reactive terminal double bonds were successfully synthesized by esterification of abietic acid dimers with undecenol and polymerized by ADMET methodology. On the other hand, we developed a “green” process to dimerize phenolic compounds derived from lignin in large quantity and high yield via enzymatic catalysis using a laccase. The main advantage of this method is that the phenolic monomer is soluble in the reaction medium while the dimer precipitates. After chemical modifications of the dimers, we built a functional bio-platform of biphenyl derivatives. The latter were then used for the synthesis of polyesters, polyamides and epoxy resins which exhibited remarkable thermal and thermomechanical properties.