Chemical Modification of Organosolv Lignin into Polyol and Preparation of Polyurethane Rigid Foam
In this study,chemical modification of organosolv lignin was carried out to synthesize lignin-based polyols and then prepared poly-urethane foam.The structure of organosolv lignin was characterized.The prepared lignin-based polyols were tested for viscosity,acid value,hydroxyl value.The thermal conductivity,compressive strength,and apparent density of the synthesized bio-based foam were tested.The results showed that the hydroxyl value of lignin-based polyol was 920 mg KOH/g,and acid value was 4.76 mg KOH/g.Viscosity of lignin polyols decreased with temperature.Viscosity reduced from 15 832 mPa·s at 25 ℃ to 3 057 mPa·s at 80 ℃.The amount of isocyanate,foaming agent,and surfactant all affected compressive strength of polyurethane foam.Finally,the lignin-based polyurethane foam showed compressive strength of 370 kPa,density of 77 kg/m3,and thermal conductivity of 0.037 1 W/(m·K)under the optimal ratio.The foaming time was shortened from 320 s to 35 s by adjusting the acid value or catalyst dosage.
万方数据
维普
