Novel bio-polyol synthesis based on date seed oil for low-density rigid polyurethane-polyisocyanurate foams

In recent years, environmental issues associated with petrol-based polyurethane foams have prompted the exploration of biocompatible resources, such as vegetable oils, for their production. Although many vegetable oils have been used to produce bio-based polyurethane foams, most of them, such as soybean and palm oil, threaten the primary sources of human nutrition due to their interference with the human food chain. Therefore, there is a pressing need to identify abundant and renewable non-edible primary sources. In this study, a new bio-polyol was synthesized from date seed ( Phoenix dactylifera L. ) as a renewable and biocompatible waste source. The date seed oil (DSO) was extracted using the Soxhlet method with n-hexane solvent. In the next step, amidation (as a green method) was used to synthesize the bio-polyol in a one-step, and solvent-free reaction. The DSO and DSO polyol were evaluated using FT-IR, 1 H NMR, and 13 C NMR spectroscopy. The key parameters of the DSO polyol, including hydroxyl number, acid value, viscosity, and thermal stability, were investigated. In the next part of this research, the DSO polyol was used to produce rigid polyurethane-polyisocyanurate foams in weight ratios of 0, 30, 50, 70, and 100 %. The foams modified with DSO polyol were evaluated using various analyses, including FT-IR, SEM, TGA-DTG, compressive and tensile strength, water absorption, and aging resistance. The effect of increasing the percentage of DSO polyol on the properties of the foams was investigated and discussed. In some analyses, the modified foams performed better than the reference foam. • Date seed oil was used as a renewable waste resource for bio-polyol synthesis. • Amidation method as a green method was used for the bio-polyol synthesis. • DSO polyol was used in the proportions of 30–100 % in the preparation of RPU-PIRF. • The effect of DSO polyol was studied on the foam samples properties.