Stability and degradation of four agricultural wastes liquefied polyols based polyurethane foams

Abstract Bio‐based polyurethane foam has attracted growing attention worldwide due to its advantages of environmental friendliness and wide range of raw materials. However, the stability and degradation ability of the newly prepared foams need to be further explored for their practical application. Four agricultural wastes (XS: oilseed rape straw/OS, rice straw/RS, wheat straw/WS, and corn stover/CS) liquefied polyols were used to replace petroleum polyol for preparing polyurethane foams (XSPU). These bio‐based foams were investigated by Thermogravimetric analysis (TGA), Fourier transformed infrared spectroscopy (FTIR), two dimensional correlate infrared spectroscopy (2D‐COS IR), water immersion test, soil burying test, and compression test to confirm their stability and degradation properties for applications. XSPU foams displayed excellent thermal stability with heating till to 240°C, appeared to change less than 0.3% in dry weight and contain more hydrogen bonds after immersing in water at 20°C for 14 days. The degradability of XSPU foams was significantly higher than that of petroleum polyol‐based PU foam as their soft segments were easier to be decomposed, where the weight loss of XSPU was up to 46.7% after burying in the soil at 23°C and 50% relative humidity for 250 days. The compression recovery ability of these bio‐based foams could reach approximately 98.2% after 1 ~ 3 times of compression test. Generally, XSPU foams displayed excellent thermal stability, stability in water, degradability in soil, and elastic ability, which showed potential application in fields of insulation, degradable plastic, and elastomer.