An intumescent flame-retardant system based on carboxymethyl cellulose for flexible polyurethane foams with outstanding flame retardancy, antibacterial properties, and mechanical properties

A novel and eco-friendly intumescent flame-retardant system based on sodium carboxymethyl cellulose (CMC) was established for wide-used flexible polyurethane foams (FPUFs). FPUF-(APP6CMC1)GN1 with extremely uniform coatings extinguished and reached the UL-94 V-0 rating, and presented an improvement of thermal insulation properties. Moreover, there was a 58 % reduction in peak heat release rate for FPUF-(APP6CMC1)GN1 compared with that of FPUF, and the microstructure analysis of char residues indicated that a perfect intumescent char layer had formed on the surface of FPUFs. Especially, CMC and GN enhanced the compactness and stability of char layers. Therefore, little volatile production was generated under the protection of physical layers in the high temperature as evaluated during the thermal degradation processes. Meanwhile, the flame-retardant FPUFs remained the ideal mechanical properties and obtained excellent antibacterial properties, and the antibacterial rates of E.coli and S.aureus were 99.9 % (FPUF-(APP6CMC1)GN1). This work provides an eco-friendlier strategy for the design of multi-function FPUFs.