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 intu-mescent 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 anti-bacterial 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.

Automated summary

This study developed a novel and eco-friendly flame-retardant system for flexible polyurethane foams (FPUFs) based on sodium carboxymethyl cellulose (CMC). The FPUF-(APP6CMC1)GN1 with uniform coatings achieved the UL-94 V-0 rating and showed improved thermal insulation properties. The addition of CMC and GN enhanced the compactness and stability of the intumescent char layer on the FPUF surface, resulting in reduced peak heat release rate and minimal volatile production during thermal degradation. Furthermore, the flame-retardant FPUFs retained their mechanical properties and exhibited excellent antibacterial properties, with a 99.9% antibacterial rate against E.coli and S.aureus (FPUF-(APP6CMC1)GN1). This research provides an eco-friendlier approach for designing multi-functional FPUFs.