Preparation and Characterization of Biopolyols and Polyurethane Foams from Liquefied Faba Bean Stalk

In this study, Faba bean stalk was liquefied for the production of biopolyols and polyurethane (PU) foams. The influences of various reaction conditions on biopolyols and PU foams were examined. Furthermore, the property relationships between biopolyols and PU foams were investigated. Biopolyols produced under the liquefaction conditions of 160°C, 90 min, 3% sulfuric acid loading, and 20% Faba bean stalk loading showed promising material properties (i.e. hydroxyl number, 496.1 mg KOH/g, acid number, 17.9 mg KOH/g, and viscosity, 1.1 Pa.s). PU foams produced from promising biopolyols showed compressive strength of 205 kPa and density of 0.035 g/cm3. The results suggested that in addition to density, the compressive strength of PU foams might also be affected by factors such as biomass residues or the chemical structures of biopolyols. The biopolyols and PU foams produced showed material properties comparable to those of conventional PU foams.