Production of bio-polyurethane (BPU) foams from greenhouse/agricultural wastes, and their biodegradability

The exploration of effective utilization of greenhouse wastes is challenging. This paper demonstrates a hydrothermal treatment approach involving the co-liquefaction of greenhouse wastes with agricultural residue in a mixed solvent of water and ethanol in the presence of a base catalyst, to convert greenhouse wastes and corn stalk into bio-oil/bio-polyol at a very high yield of 57.2%, accompanied by a very low yield of solid residue. This bio-oil (hydroxyl number: 305 mg KOH/g) was successfully used as bio-polyol to substitute up to 50% petroleum-based polyol for the preparation of bio-polyurethane (BPU) foams. The biodegradability of the BPU foams was also studied by incubation with Dyella sp. for a period of 8 weeks. The weight loss, Fourier-transform infrared (FTIR) spectra, thermogravimetric analysis (TGA) results, and scanning electron microscopy (SEM) images of foam samples were collected and analyzed. The BPU foams exhibited much better biodegradability than the petroleum-based polyurethane (PU) foam. (c) 2022 Society of Chemical Industry and John Wiley & Sons, Ltd