Development and characterization of lignin-furan rigid foams by varying precursors and catalyst concentration

Foams from fossil fuel-based raw materials have been developed into crucial industrial products for a wide range of applications. However, they come with sustainability and environmental challenges. Bio-based foams hold promises for replacing fossil fuel-based foams because of their low cost, superior thermal insulation performance, superior fire resistance, eco-friendliness, bio-sourced origin, and environmental sustainability. This study synthesized rigid bio-based foams from plant-derived precursor chemicals: furfuryl alcohol (FA) and polyol produced from lignin. FA was obtained from reducing furfural derived from maize cobs via acid hydrolysis. Eight bio-based foams were obtained by varying the catalyst concentration and the ratio of FA to the lignin-based polyol and subsequently characterized. Resulting bio-based foams had compressive resistance: 14–16 MPa, water absorption capacity: 24.12–332.14%, density: 0.247–0.886 g/cm 3 , and moisture content: 7.90–9.7%. Scanning electron microscopy images revealed that the foam cellular morphology was closed cells with the cell diameter between 10 and 200 µm. Thermogravimetric analysis data showed that maximum thermal degradation in the produced foams occurred between 457.4 and 453 °C. The outlined results indicated that the foams are suitable for thermal insulation, construction, and floral purposes due to their high thermal stability, high water absorption capacity, and high compressive strength.