Abstract: Acid treated with HNO3, ion-exchanged with NaCl, and intercalated with hexadecyltrimethylammonium bromide (HDTMA·Br), organic rectorite (OREC) was prepared and used in polypropylene (PP)/intumescent flame retardant (IFR) composites. The synergistic flame-retarding effect of OREC and IFR was investigated. The composite was characterized using XRD, LOI, TG, and SEM. It was found that the layers of organic rectorite were delaminated by PP chains. There was a clear synergistic effect between OREC and IFR. When 2 % of OREC was introduced, the LOI increased by 4.8 %, the carbon residue increased to 22 %.

Key words: polypropylene, rectorite, intercalation, synergistic retarding, intumescent flame retardant