Biobased rigid polyurethane foam prepared from apricot stone shell-based polyol for thermal insulation application, Part 1: Synthesis, chemical, and physical properties

Polyurethane foam is one of the most versatile construction insulation materials because of its low density, high mechanical properties, and low thermal conductivity. This study examined biobased rigid polyurethane foam composites from apricot stone shells, which are lignocellulosic residues. The apricot stone shells were liquefied with a PEG-400 (polyethylene glycol-400) and glycerin mixture in the presence of sulfuric acid catalyst at 140 to 160 °C for 120 min. Rigid polyurethane-type foam composites from the reaction were successfully prepared with different chemical components. Biobased polyurethane-type foam composites were successfully produced from the liquefied apricot stone shells. The FTIR spectra of liquefaction products confirmed successful liquefaction of products and that they are sources of hydroxyl groups. The liquefaction yield (81.6 to 96.7%), hydroxyl number (133.5 to 204.8 mg KOH per g), the highest elemental analysis amount (C, H, N, S, O) (62.08, 6.32, 6.12, 0.13, and 25.35%), and density (0.0280 to 0.0482 g per cm3) of the rigid polyurethane foam composites were comparable to foams made from commercial RPUF composites.