Phytoremediation-derived sunflower oil for bio-based polyurethane foams

Sunflowers were planted for phytoextraction of heavy metals from a contaminated effluent-exposed soil substrate. Oil pressed from the sunflower seeds was used as natural, renewable resource for the production of biopolyol and, subsequently, different polyurethane biofoams. The oils were modified via transesterification with triethanolamine (TEA). The biopolyols were characterized using instrumental methods, including FTIR, gel chromatography (GPC), 1 H and 13 C NMR and MALDI-TOF MS. The biopolyols obtained from remediation (O-R) and commercial (O-C) sunflower oil were characterized by a hydroxyl number above 300 mgKOH/g and a viscosity below 200 mPa⸱s. Such properties make the biopolyols usable in the production of different types of polyurethane foams, such as open-cell foams for attic insulation and viscoelastic foams intended for pillows or mattresses. The polyurethane foams were subjected to an analysis of their physical and mechanical properties, including apparent density, thermal conductivity, resilience and compressive strength, as well as an investigation of their chemical structure using FTIR and their cellular structure. In addition, it was confirmed that oilseeds from plants used for phytoremediation of degraded soils could be used as a potential source of raw materials for polyurethane chemistry. The resulting biopolyols can replace petrochemical polyol entirely in open-cell insulation foams and up to 20 % in viscoelastic foams. • Sunflower was used for phytoremediation and watered with landfill leachate. • Oil from phytoremediated sunflowers returned to the raw material cycle. • Biopolyol from phytoremediation (OH number ∼330 mgKOH/g) usable in PU materials. • Modified phytoremediation oil replaced 20 % petro-polyol in viscoelastic foams. • Modified phytoremediation oil replaced 100 % petro-polyol in insulation foams.