Novel incorporation of mesoporous NiCo2O4 into thermoplastic polyurethane for enhancing its fire safety

Abstract

In this work, two kinds of NiCo₂O₄ particles are synthesized and their structures are confirmed from X-ray diffraction patterns and Fourier transform infrared spectra. The excellent dispersion of the particles in thermoplastic polyurethane (TPU) is confirmed by transmission electron microscopy. Char residue yield of TPU is enhanced obviously after the incorporation of NiCo₂O₄, suggesting a catalyzing carbonization effect. Toxic gases released from decomposition of the polymer, such as HCN, are fatal to humans, so it is of great significance to evaluate the toxic gases from TPU composites by thermogravimetric analysis/infrared spectrometry. The release of HCN is inhibited effectively by NiCo₂O₄, and this can be attributed to the gas adsorbing and barrier effects of the mesoporous particles. In addition, the amount of flammable gases is also reduced markedly. Moreover, the peak heat release rate and total heat release of TPU are decreased appreciably by NiCo₂O₄ with a higher specific surface area.