Two‐step preparation of phosphorus‐containing organoclay and its effect on fire‐resistant and mechanical properties of the flame‐retardant polyethylene composite

Abstract In this study, a nanohybrid based on montmorillonite (oMMT 2 ) was prepared through a two‐step method using Arquad MCB‐80 and 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) as intercalation agents. The nanohybrid exhibited a basal spacing of 31.5 Å, which contained approximately 12.3% of Arquad MCB‐80 and 31.6% of DOPO. Various amount of oMMT 2 nanohybrid was incorporated into a flame‐retardant polyethylene system containing aluminum trihydroxide and red phosphorus with a constant total additive content of 20 wt%. The dispersibility of oMMT 2 in the composite matrix was evaluated by energy dispersive x‐ray mapping and x‐ray diffraction analyses. At a content of 3 wt% in the nanocomposite, oMMT 2 showed a highly exfoliated state, while at a 5% content, a partially exfoliated and intercalated state was observed. A synergistic flame‐retardant effect between the nanohybrid and the mixture of aluminum trihydroxide and red phosphorus was found. The nanocomposite loading 3 wt% oMMT 2 demonstrated the best flame retardancy, achieving a V‐0 rating of the vertical burning test with a limiting oxygen index of 27.6%. Moreover, the addition of the low oMMT 2 contents (≤3 wt%) improved the mechanical properties of the flame‐retardant composite.