Alkali lignin depolymerization under eco-friendly and cost-effective NaOH/urea aqueous solution for fast curing bio-based phenolic resin

It is still a challenge to use lignin without any pretreatment due to its high molecular weight, strong steric hindrance, and low reactivity. To prepare value-added low molecular weight aromatic compounds for preparation of lignin-based phenolic resins, alkali lignin (AL) was depolymerized under low cost and environmental-friendly NaOH/urea aqueous solution at low temperature in this paper. The molecular structure changes of the depolymerized AL...