Study on the thermal decomposition kinetics and flammability performance of a flame-retardant leather

A flame-retardant leather (FR-leather) was prepared from blue wet leather treated with tetrakis hydroxymethyl phosphonium–melamine–pentaerythritol diphosphorate (THPM). An optimized genetic algorithm search method driven by Kissinger method was employed to estimate pyrolysis kinetic mechanism and the thermal stability of FR-leather. It is shown that the thermal decomposition of leather in nitrogen is a three-step kinetic scheme composed of the pyrolysis of triglyceride, multi-complexation collagen and single-complexation collagen, and the activation energies of the corresponding components of FR-leather are, respectively, 84.1, 172.6 and 253.6 kJ mol −1 . Accordingly, those of blank leather are 69.3, 161.3 and 105.4 kJ mol −1 . Meanwhile, cone calorimeter test demonstrates that when leather was treated with THPM, total heat release and total smoke production are decreased, respectively, 16.2 and 54.5%, and time to ignition increased from 20 s of blank leather to 26 s of FR-leather. The results of limit oxygen index value increased from 26.1% of blank leather to 32.9% of FR-leather, and the results of UL-94 vertical burning tests of FR-leather are significantly decreased, such as flame combustion time and length of carbonization decreased 88% and 72%, respectively. It is shown that the novel THPM material obviously improved the thermal stability and flame-retardant properties of leather fibers; at the same time, it has good smoke suppression effect and is an excellent flame retardant suitable for leather.