Figure 7
From: Investigation of bio-based rigid polyurethane foams synthesized with lignin and castor oil
Bio-based polyurethane foam structure obtained by SEM images. (a) LPU foams with the addition ~ 20 wt% kraft lignin (index 1.01), (b) lpu foams with the addition of ~ 20 wt% of kraft lignin (index of 1.3), (c) CPU foams with the addition of ~ 100 wt% of castor oil (index of 1.01).
