Thermal and mechanical behaviour of flexible polyurethane foams modified with graphite and phosphorous fillers

Abstract

Flexible polyurethane foams (FPF) are polymer materials that have high flammability. Fyrol PNX (FPNX) and expandable graphite (EG), have been used to modify the properties of these materials. The aim of this study was to assess the possibility of improving the thermal stability and flame retardancy of FPF by the addition of FPNX and EG fillers. The prepared foams were characterised by their apparent density, hardness, flexibility, irreversible strain and linear flammability, as well as thermogravimetric analysis (TGA), dynamic mechanical analysis, Fourier transform infrared spectroscopy (FT-IR) and pyrolysis combustion flow calorimetry (PCFC) measurements. The apparent density, hardness, flexibility and irreversible strain results showed that the addition of graphite and phosphorous fillers to the FPF makes slight changes to the mechanical properties, which remain within the acceptable norms. It was also observed that reducing the amount of Fyrol PNX and replacing it with the same amount of EG allowed similar values of linear flammability to be obtained with a simultaneous increase in thermal stability, as shown in the TGA study and the PCFC test. Moreover, it was found that the modification of flexible polyurethane foam by the addition of a mixture of FPNX and EG fillers allows the best properties of this type of materials to be obtained. This result indicates that this type of modification could be an effective way to improve the thermal stability of FPF.

Intumescing multilayer thin film deposited on clay-based nanobrick wall to produce self-extinguishing flame retardant polyurethane

“…A common technique for retarding the flammability of PUF is to introduce bromine-based molecules that scavenge (H • and OH • ) radicals in the gas phase [5,6], but these halogenated additives are undergoing worldwide scrutiny for the toxic smoke they release and their potential to leach into the environment [7][8][9]. Platelet-based and intumescent nanocoatings have been developed in recent years to address these issues [10][11][12][13][14][15][16][17][18][19][20].…”

Studies on Flexible Polyurethane Foam With Improved Flame Retardancy

“…The decomposition of developed PUF F was performed in the temperature range from 30 o C-800 o C. The thermal stability was assayed at 5 % and 50 % weight loss of PUF F samples. 5 % and 50 % weight loss corresponds to the initial and soft segments decomposition respectively [24]. …”

Influence of expandable graphite on flame retardancy and mechanical properties of organic–inorganic hybrid material based on sodium silicate and polyisocyanate

“…They indicated that the thermal stability and fire resistance of high-density polyethylene/ethylene vinyl-acetate blend were enhanced significantly by EG and improved with decreasing particle size of EG. Besides, the possibility of improving the thermal stability and flame retardancy of flexible polyurethane foams by the addition of expandable graphite fillers has been assessed by Wolska et al [20], and it revealed the modification by the addition of expandable graphite was an effective way to improve the thermal stability of flexible polyurethane foam.…”