Evaluation of the reactive molecular dynamics method for Research on flame retardants: ATH-filled polyethylene

We carried out reactive molecular dynamics simulations based on the ReaxFF reactive force field to study the effect of aluminium (tri)hydroxide on the thermal decomposition of polyethylene. The simulations reproduced the endothermic decomposition of aluminium (tri)hydroxide into alumina and water. Other known mechanisms of flame retardancy, such as heat absorption by the filler and its residue, were reproduced with reasonable accuracy. The simulations also revealed a chemical interaction between polyethylene and aluminium (tri)hydroxide, in which hydroxyl radicals released by the aluminium (tri)hydroxide abstracted hydrogen from the surrounding polyethylene, resulting in enhanced water production and enhanced charring of polyethylene. Based on our results, we consider reactive molecular dynamics simulations a promising tool for investigating existing and emerging flame retardant concepts, and the pyrolysis chemistry of flame retardant polymer systems.