Lignin valorization: Old and new lessons

The renaissance in lignin chemistry and biochemistry has been driven by modern biorefining concepts. It has matured from the role lignin plays in the recalcitrance of biomass for biological conversion to biofuels, to lignin valorization. Broadly speaking lignin has been viewed as a means to generate chemical monomers via dolymerization and conversion, or utilization of the lignin polymer for material applications. In the latter route over the past decade the research committee has come to appreciate that lignin's structural poly-dispersity is detrimental to optimizing its physical properties in many polymeric application. Research has shown that this can be readily addressed using several fractionation technologies yielding lignin streams with relatively "uniform" structural features. In our studies we have explored these principles in the synthesis of advanced lignin derived polyurethanes and consistently shown improvements in the final physical properties. This presentation will highlight these findings and discuss what future efforts are still needed.