Synergistic Adenosine Triphosphate/Chitosan Bio-coatings on Polyurethane Foam for Simultaneously Improved Flame Retardancy and Smoke Suppression

Abstract

Considering that fire safety is a persistent problem for most polymeric materials, including polyurethane (PU) foam, the demand for flame retardants (FRs) is growing. However, the use of conventional FRs containing halogenated and brominated chemicals has been continuously regulated owing to their toxicity. Here, we demonstrate the layer-by-layer (LbL) coating of negatively charged adenosine triphosphate (ATP) and positively charged chitosan (CS) as the synergistic FR on PU foam, a model flammable polymer material. The FR performance of the PU coated with LbL-assembled ATP and CS (ATP/CS-PU) was tested, and the results suggested that the ATP/CS layers were finely deposited on the surface of the PU without damaging the structure. Only five bilayers (5BL) were sufficient to impart excellent fire retardancy, which exhibited a limiting oxygen index value of 35% and the HF-1 rating in the UL94 foamed material horizontal burning test. In addition, ATP/CS(5BL)-PU showed a significant reduction in the peak heat release rate of 42.0% and in the total smoke release of 30.6% compared to that of bare PU (b-PU). Furthermore, the ATP/CS coatings did not deteriorate the mechanical properties of b-PU. Finally, combined thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR) showed that ATP/CS(5BL)-PU was safe because it suppresses hazardous gases, which is the main problem with conventional FRs.

Lightweight Biobased Polyurethane Composites Derived from Liquefied Polyol Reinforced by Biomass Sources with High Mechanical Property and Enhanced Fire-Resistance Performance

“…On the other hand, PU foam has been used in different domains including furniture, vehicles, and construction due to its outstanding characteristics such as lightweight, low electrical conductivity, good thermal insulation, and good mechanical properties. PU composite foam is also known as high insulating and acoustic performance material. − However, materials based on PU have some drawbacks as its inherent flammability − and the amount of heat and smoke produced when it was burned, causing damage to property and even human health. In particular, biobased polyurethane [biobased insulation polyurethane (BPU)] foam is even more sensitive to fire, so one of the main objectives of this study is to improve the flame retardant (FR) performance of BPU composite foams.…”

“…PU composite foam is also known as high insulating and acoustic performance material. 15 − 17 However, materials based on PU have some drawbacks as its inherent flammability 18 − 21 and the amount of heat and smoke produced when it was burned, causing damage to property and even human health. In particular, biobased polyurethane [biobased insulation polyurethane (BPU)] foam is even more sensitive to fire, so one of the main objectives of this study is to improve the flame retardant (FR) performance of BPU composite foams.…”

Ultralight, Hydrophobic, Fire-Resistant, and Highly Thermally Insulating Aerogel by Cross-Linking Cellulose Nanofiber with Tannin and Adenosine Triphosphate

“…Inorganic aerogels, such as silica, exhibit low thermal conductivity, but have limitations such as brittleness, low mechanical strength, and toxicity, which restrict their practical use . Organic aerogels, such as polyimide, polyurethane, and resorcinol-formaldehyde, are formable, but their synthesis and fabrication processes are complicated and involve toxic sources, leading to environmental pollution. − Therefore, there has been focus on the development of next-generation aerogels based on natural resources as a replacement for petroleum- and mineral-based materials . This is because nature provides abundant resources sustainably at a low cost and without toxicity. − …”