Valorization of Lignin Side-Streams into Polyols and Rigid Polyurethane Foams—A Contribution to the Pulp and Paper Industry Biorefinery

Valorization of industrial low-value side-streams are great interest, contributing to boosts in the circular economy. In this context, lignin pulp and paper industry were oxypropylated produce biobased polyols tested synthesis rigid polyurethane (RPU) foams. E. globulus lignins, namely a isolated from an Kraft black liquor depolymerized lignins obtained as by-products oxidation process, used. RPU foams, synthesized with 100% lignin-based using 1.1 NCO/OH ratio, characterized concerning apparent density, morphology, thermal conductivity, stability, heat release rate (HRR). Foams containing presented densities varying 44.7 112.2 kg/m3 conductivity range 37.2–49.0 mW/mK. For reference foam (sample produced wt. Daltofoam TP 32015 polyol), values 70.9 41.1 mW/mK obtained, respectively. The achieved results point out viability generated at content mainly when Moreover, fire retardancy was favored introduced. proposed strategies can contribute establishing integrated biorefinery concept where material (polyols foams) be combined chemical production (vanillin syringaldehyde).