Production of rigid bio-based polyurethane foams from sugarcane bagasse

Current polyurethane products (PUs) rely heavily on two feedstocks that are primarily petroleum-derived, leading to significant social and environmental concerns. This study examined utilisation of the sugarcane bagasse-based-bio-oil produced from hydrothermal liquefaction (HTL) with glycerol co-solvent, as an alternative resource to produce bio-based PU foams. The influences of HTL conditions such as glycerol loading (0–50 wt%) and alkaline catalyst concentration (0.05–1 M K2CO3) as well as the loading of bio-oil replacing polyol in the PUs formulation (0–100 wt%) on the thermal stability and mechanical properties of PU foams are investigated in this work. The FTIR results confirm the successful reaction of isocyanate and bio-oil’s hydroxyl groups, producing urethane linkages. Although increasing the amount of bio-oil as polyol (25–100 wt%) in PUs formulation remarkably reduced the thermal stability of the produced foams in the first stage of degradation (150–230 ℃), it conversely increased in the second stage (350–450 ℃). The PU foams incorporated with 50 wt% bio-oil afforded a remarkable compressive strength of 280–450 kPa. This study demonstrates insights into synthesizing sustainable bio-based PUs from agricultural waste biomass, thereby providing a fundamental understanding of the practical application of green PU foams.