Simultaneously heat and smoke suppression of thermoplastic polyurethane withdeveloping an Intumescent flame retardant system

The aim of this work is to develop an efficient intumescent flame retardant (IFR) system for thermoplasticpolyurethane (TPU) composites with improved fire behavior via significantly reduced heat and smokerelease. Three TPU/IFR composites were prepared by loading different amounts of IFR componentsconsisting of ammonium polyphosphate (APP), Pentaerythritol (PER), and melamine polyphosphate (MPP).Flame retardancy was investigated by limiting oxygen index (LOI), UL-۹۴ test and cone calorimeter. Basedon the results, the LOI values of TPU/IFR composites increased up to ۷۰% compared with that of originalTPU, and the UL-۹۴ tests could pass V-۰ rating. Cone calorimeter results indicated that the IFR system wasefficient, leading to significant heat and smoke suppression. The best performance of IFR was achieved byadding ۴۰wt. % of APP, ۱۰wt. % MPP, and ۱% wt.% PER in which peak heat release (PHR) and total smokerelease (TSR) were reduced by ۸۰% and ۷۱.۶%, respectively, compared with the original TPU. The thermalstability of the final formulation of the IFR-TPU was studied by thermogravimetric analysis (TGA/DTG) andcompared with the reference TPU. TGA/DTG curves confirmed the desired performance of the IFR systemby earlier thermal degradation of IFR compared with original TPU. This increased the char residue by ۲۵%compared to ۰.۲% for the original TPU, resulted in the improvement of thermal stability and flameretardancy.

Keywords:

Thermoplastic polyurethane , Flame retardant , Intumescent , Heat release , Total Smoke release , Cone calorimeter