Submitted Abstract
Omnipresent in Nature, polyphenols are naturally occurring phenolic compounds with well-known anti-oxidant properties. Over 8000 thousands phenolic structures have been identified with polyphenols. Among them, lignin is produced in large amount from agricultural wastes and by-products. Lignin is generally considered as a macro-building block for the elaboration of polymer materials like polyurethanes or polyesters. The impact of these conversions remains up to now quite reduced since the chemical transformation needed to convert lignin into commodity polymers remain expensive, and lignin is mainly valorised as combustible source.Benzoxazine (Bz) are a new class of mono-component thermosets obtained from the readily condensation of a phenol and an amine. Benzoxazine chemistry is finding a hike through the preparation of its monomers from renewable resources, in particular lignin-like derivatives (for instance vanillin, eugenol or gaiacol). However, these monomers can suffer from process difficulties hampering their developement. Recently, we have shown the processability of these derivatives can be widely improved by the formation of suitable benzoxazine monomers.In the project LIGNOBENZ, we envision to apply a similar approach, directly on lignin. We hypothesize that it is possible to produce a high performance, liquid, self-condensing benzoxazine resin from lignin possessing a unique properties profile. In particular, we propose that the presence of a range of structures and molecular weights, inherent to lignin, should lead to materials with a mechanical toughness across a range of temperatures, while the polyphenolic structures it contains should favor anti-oxidant properties. The success of this project will result in the transformation of a low value biobased waste material into a high value renewable resin with broad relevance to a range of important applications. These include can coatings, corrosion protection layer, and all the applications where a stiff coating with good toughness and dissipation across a range of temperatures would be necessary.