Turning Fruit Seed Oils into High-Performance Open-Cell Polyurethane Foams: A Green Route to Petrochemical Polyol-Free Insulation

Five types of fruit seed oils have been described from the perspective of their potential use in the synthesis of biopolyols. The overall goal is to increase the participation of biopolyurethanes in polymer production, aligning with the European Green Deal. Blackcurrant, cherry, grape, pomegranate, and watermelon seed oils were characterized by iodine value, acid value, density, average molecular weight, viscosity, and fatty acid profile. The thermal properties of the oils were also determined using thermogravimetry (TGA) and differential scanning calorimetry (DSC). In order to obtain reactive compounds for the synthesis of biopolyols, the vegetable oils were modified using the transesterification reaction with triethanolamine. The resulting biopolyols were characterized by their hydroxyl number, acid number, density, average molar mass, and viscosity. The biopolyols were then used to produce thermal-insulating polyurethane foams by completely replacing petrochemical polyols with counterparts derived from fruit seeds. The obtained foams were described by their closed cell content, apparent density, thermal conductivity coefficient, dimensional stability, maximum stress at 10% deformation, thermal stability, oxygen index, and water absorption. In addition, an analysis of the foaming process revealed that the properties of fruit seed oil after chemical modification had an impact on the properties of the open-cell polyurethane foams and the foaming process itself.