Packaging of ZIF-8 into diatomite sealed by ionic liquid and its application in flame retardant polyurea composites

Diatomaceous earth (DE) has abundant silicon elements and unique pore structure, and has a good application prospect in the field of flame retardants. However, the compatibility between DE and polymers still needs to be improved. In this manuscript, imidazole-based metal organic framework (ZIF-8) was ingeniously filled into the pores of the biomorphic DE as an obstacle, and ternary (Si-P-N) composites (DE@ZIF@ILs) were obtained by introducing phosphorus-containing ionic liquids (ILs) on its surface. It effectively improves the problem of poor mechanical properties of polymer composites caused by large-size DE. The results of the cone test showed that the introduction of DE@ZIF@ILs effectively reduced the fire hazard of polyurea (PUA). The peak heat release rate, total heat release, peak smoke production rate and total smoke production decreased by 49.7%, 45.3%, 53.0% and 41.4%, respectively. This study also explored the specific mechanism of flame retardant and smoke suppression of DE@ZIF@ILs.