Lignin-based polyurethane and epoxy adhesives: a short review

Purpose: of this paper was to review and summarize significant papers related the development characterization lignin-containing adhesives: polyurethane epoxy types. In last decades, several efforts have been dedicated on renewable raw materials for polymer synthesis, mainly due petroleum depletion sustainability. context, lignin emerged as a potential candidate substitute fossilbased in adhesive synthesis formulations. Design/methodology/approach: Recent other relevant were reviewed, aiming identify main advantages limitations involved incorporation into adhesives First, effects unmodified addition presented. Afterwards, chemical modification methods presented discussed, based thermomechanical results. Findings: Incorporation usually is limited 30 %wt., otherwise mechanical properties are drastically affected consequence poor solubility excessive brittleness. Lignin can be used increase reactivity hydroxyl groups and/or add new moieties its molecular structure, improving cured adhesives. Practical implications: years, some industrial plants started operate produce technical grade at scale, with reproducible controlled structure. Therefore, increasing from researchers chemists develop lignin-based technologies, which work directly contribute with. Originality/value: As high content phenol mostly applied phenolic resins wood For first time literature, summarizes advances epoxy, Results support application biobased, well revalorization valuable readily available biomass.