Synergistic Mechanism of Synergist in PP/IFR System

Abstract: The synergistic effect of synergists in polypropylene(PP)/intumescent flame retardant(IFR) was investigated. The results of LOI and UL 94 testing indicated that each synergist could improve the flame retardant property. The synergists could be divided into three types according to their synergistic mechanism as determined by TGA: Those couldn’t react with APP or PER; Those only reacted with APP but not PER; Those could react with both APP and PER. The residue char layer was characterized by SEM and char layer strength measurement. The results showed that the synergists could strengthen the char layer and promote the isolation of heat and oxygen by attaching on the surface of substrate although they have different reaction mechanisms.