Study on the char-forming and synergistic flame retardant performance of SEBS/HIPS/PPO composites applied for cable

The halogen-free flame retardant (HFFR) styrene-ethylene-butylene-styrene (SEBS)/high impact polystyrene (HIPS)/polyphenylene oxide (PPO) composites filled with aluminium hypophosphite (AHP) and melamine cyanurate (MCA) had been prepared. The thermal stability, flame retardancy, carbon slag structure, mechanical and rheological properties of SEBS/HIPS/PPO composites had been investigated. The research results showed that the thermal stability and flame retardancy of SEBS/HIPS/PPO composites were significantly improved, and there was obvious intumescent FR (IFR) synergism between AHP and MCA. Meanwhile, the role of AHP and MCA in char-forming promotion and carbon slag enhancement was also an important reason. Scanning electron microscopic (SEM) images showed that the char residual structure of sample A-4 showed more compact than that of A-3 which was similar to agglomerated loose sand, and that of A-2 presented an intumescent structure of twisted flake carbon slag after combustion of cone calorimeter. The ultimate tensile strength increased slightly because of the addition of PPO.