Flammable and mechanical effects of silica on intumescent flame retardant/ethylene-octene copolymer/polypropylene composites

The flammable and the mechanical effects of silica (SiO2) on the halogen-free, flame-retarded ethylene-octene copolymer (POE)/polypropylene (PP) composites were investigated. Through the thermal stability analysis and the combustion test, it was found that the SiO2 had a synergistic effect on the intumescent flame retardant (IFR), especially when the SiO2 content was 3 wt%. According to the results of mechanical properties, the tensile strength of composites increased with the rising SiO2 content and most of the impact strength is retained. The fracture morphology showed the state of SiO2/IFR particles in the POE/PP blends, which reflected that with the increasing SiO2 content and the decreasing IFR content, the aggregates became less compact and the size of aggregates became smaller.