Mechanically Sustainable Starch-Based Flame-Retardant Coatings on Polyurethane Foams

The use of halogen-based materials has been regulated since toxic substances are released during combustion. In this study, polyurethane foam was coated with cationic starch (CS) and montmorillonite (MMT) nano-clay using a spray-assisted layer-by-layer (LbL) assembly to develop an eco-friendly, high-performance flame-retardant coating agent. The thickness of the CS/MMT coating layer was confirmed to have increased uniformly as the layers were stacked. Likewise, a cone calorimetry test confirmed that the heat release rate and total heat release of the coated foam decreased by about 1/2, and a flame test showed improved fire retardancy based on the analysis of combustion speed, flame size, and residues of the LbL-coated foam. More importantly, an additional cone calorimeter test was performed after conducting more than 1000 compressions to assess the durability of the flame-retardant coating layer when applied in real life, confirming the durability of the LbL coating by the lasting flame retardancy.

Automated summary

The study developed an eco-friendly, high-performance flame-retardant coating agent by coating polyurethane foam with cationic starch (CS) and montmorillonite (MMT) nano-clay using a spray-assisted layer-by-layer (LbL) assembly. Experimental results confirmed that the coating significantly reduced the heat release rate and total heat release of the foam, improving its fire retardancy. Additionally, durability testing showed the long-lasting flame retardancy of the LbL coating even after more than 1000 compressions.