Halogen-free flame-retardant flexible polyurethane for textile coating: Preparation and characterisation

A type of flexible polyurethane (FPU) based on renewable-sourced polyol was prepared and then modified with halogen-free flame retardants, namely, alumina trihydrate (ATH) and triphenyl phosphate (TPhP), to further increase its flame-resistant properties. The optimum loading for additives was determined based on analysing the changes in physicomechanical properties, thermal properties, and flame-retardant behaviours of modified FPU materials. An FPU-coated textile was then prepared; its smoke-generating behaviours and flammability were investigated in comparison with pristine fabric, pristine FPU, and respective modified FPU. The results confirmed good synergistic effect between ATH and TPhP, which helped increasing flame-resistant properties of applied materials, while also maintained reasonable flexibility for fabric-coating applications. However, the usage of modified FPU as coating material also proved to cause more toxic smoke emissions during the short burning duration of coated-fabric, an issue that needed to be investigated more thoroughly in order to guarantee the safety of people during catastrophic events.