Lignin: A Platform for Renewable Aromatic Polymeric Materials

Abstract

Lignin is the most abundant renewable aromatic material on Earth and is a logical link in the sustainable supply chain of the chemicals and materials that today we derive mostly from fossil-based benzene. In this chapter, we review lignin's industrial sources and the recent progress in developing polymeric materials that use lignin as a macromonomer, polymer blend, functional additive, and precursor for advanced carbon materials. Several high-purity lignin production facilities were installed recently at pulp mills in three continents. Additional lignin availability is expected as second generation biofuel biorefineries realize that it makes sense to add value beyond the energy content of the lignin-rich residues that they generate. In the last decade, many lignin applications have seen significant progress, including lignin use in thermoset resins, polyurethanes, polyesters, polymer blends, elastomers, smart memory materials, antioxidants, functional packaging, electrically conductive materials for energy storage, coatings, advanced carbon materials, engineering plastics, ingredients for inks and varnishes, UV light blockers, coatings, compostable plastics, foams, rubber products, insulation, sealants, fiber composites, etc. Several of the applications highlighted here have already entered commercialization, while many others are expected to do so within the next few years. Increasing lignin use will result in environmental benefits and products with reduced carbon footprint. Application to lignin of emerging technologies may open new routes for lignin valorization in the near future.