Fire-resistant bio-based polyurethane foams designed with two by-products derived from sugarcane fermentation process

Abstract There is a great interest in replacing conventional fossil-based polymers and composites with inorganic or organic waste-based materials and filler-type additives, to promote environmental sustainability and circularity. The main objective of this study was the design of water-blown polyurethane rigid foams integrating two by-products derived from the Amyris fermentation process of production of β-farnesene. The distillation residue (FDR) was used as main polyol component in the neat formulation of the foams (PF) that it was supplemented (PFA) with 4.5% of sugarcane bagasse ash (SCBA) added as a filler with fire-retardant properties. The impact of both by-products on the foam density and morphology, and in the thermal, mechanical, and flame-retardant properties was assessed. SCBA presence led to a reduction in apparent density, cells size, and glass transition, delaying the thermal decomposition. The differences observed in the thermal conductivity and flammability test parameters suggest a visible impact of the ash incorporation, thus meeting the fire protection standard UL 94, class HB. Highlighting the need for further optimization, this work presents a practical example of the integration of different wastes derived from the same fermentation process in the formulation of sustainable PUR foams with reduced flammability.