Developing fire retardant composites of polypropylene with APP and OS retardant

Abstract A composite flame retardant was formed by flame retardant ammonium polyphosphate (APP) and carbon source oxidized starch (OS) to modify PP by melt blending with PE. The aim is to preserve the mechanical properties of polypropylene while further improving its flame-retardant properties. Through vertical and horizontal combustion tests, combustion process analysis, and SEM microstructure analysis, it can be seen that the addition of the composite flame retardant system effectively increased the residual carbon content and suppressed flame development and smoke release. Its synergistic effect effectively improved the flame-retardant performance of polypropylene composite materials. Mechanical tests show that the mechanical properties of PP flame retardant materials can meet the general requirements for using flame retardant materials.