| Abstract | This research aims at improving the integration of lignin in polyurethane (PU) rigid foams. First, lignin was chemically modified to introduce amine groups on its molecule. The purpose of this step is to enhance the lignin direct reactivity with isocyanate to form urea bonds and also to use this modified lignin as a catalyst for the main reaction involving polyol and isocyanate. A simple one-step approach, without toxic solvent, was used for this modification. The efficiency of this modification was verified using Fourier transform infrared spectroscopy (FTIR), electron dispersion X-ray (EDX) and scanning electron microscopy (SEM). Then, the resulting modified lignin was incorporated at 1 O and 20 wt % in the formulation of PU rigid foams. The influence of lignin on foaming ability was also evaluated , ln addition, the effect of modified lignin on mechanical properties, thermal conductivity and density of the foam was also investigated. |
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