Fabrication of ultraviolet resistant and anti-bacterial non-isocyanate polyurethanes using the oligomers from the reductive catalytic fractionated lignin oil

Under the 'green chemistry' concept, lignin oligomers obtained from the reductive catalytic fractionation process was utilized as the renewable polyol substitute for non-isocyanate polyurethane (NIPU) films. After fractionation and characterization, the lignin oligomers underwent oxypropylation and were subsequently prepared as ochlorohydrin resins. Then, the obtained cyclic carbonate (CC) was reacted with amines-based molecules for the fabrication of NIPUs. Owing to the low molecular weight, high hydroxyl group content, and good solubility, the obtained NIPUs substituted with the RCF lignin oligomers derived CC exhibited satisfactory mechanical properties and thermal stability. More attractively, the NIPUs possessed excellent UV resistant property and antibacterial activity, revealing that the RCF lignin-based NIPUs can be potentially applied as the antibacterial coating, protective coating, and anti-ultraviolet materials. These findings opening a new approach for valorization of the low valuable oligomer fractions in the RCF oil, which improving the overall economic feasibility of the lignin-first biorefineries.