Bio-functional nanocellulose/lignocellulose-based polyurethane nanocomposite foams with enhanced flame retardancy, thermal conductivity, and thermal stability

The necessity of developing a green, circular, and sustainable process to produce high bio-content building materials has directed current research trends. In this paper, we introduce a novel high bio-content-based polyurethane (BPU) nanocomposite foam that is prepared using 100 % bio-polyol and nanocellulose fiber (CNF). Both the bio-polyol and CNF are obtained from bamboo biomass to limit the environmental footprint of petroleum-derived materials. In addition, environmentally-friendly non-halogen flame retardants (FRs) are incorporated into BPU nanocomposite to enhance fire safety, mitigate fire risks, and advance the development of fire-resistant insulation materials and construction technologies. The BPU and BPUC₅ nanocomposite foams completely burnt to the holder clamp with a low LOI value and did not pass the UL94 HB standard. With the loading of FR, the BPUC₅ nanocomposite foam reached V-0 rating and the LOI value significantly increased up to 21–42 %. The cone calorimeter results showed that the peak heat release rate of BPUC₅/FR nanocomposite foams notably decreases by 30.3–42.3 %. These foam materials present a significant potential in thermal insulation applications for the field of biobased building materials for a sustainable future with low carbon emissions and circular economy. In addition, their ultra-lightness is a major advantage in comparison to other bio-insulating materials and PU foams.