Synergistic effects of zeolites on a novel intumescent flame-retardant low-density polyethylene (LDPE) system

A char forming agent and silica-gel microencapsulated APP were selected to form novel intumescent flame-retardant system (IFR) to prepare flame-retardant low-density polyethylene (LDPE) composites, and then the influence of zeolites on the thermal and flame-retardant properties of flame-retardant LDPE composites were studied. With the addition of 1 wt% zeolites to LDPE/IFR system, the LOI value increases from 29.0 to 34.0 %. The results of cone calorimetry show that the heat release rate peak and total heat release of the intumescent flame-retardant LDPE composite with 1 wt% zeolites decreases remarkably compared with that of without zeolites. The scanning electron microscopy indicates zeolites with suitable content can improve the quality of the char layer of flame-retardant LDPE composite which is more coherent and dense. The zeolites with the appropriate content can remarkably improve the flame-retardant properties of the LDPE composites.