Abstract: flame retarding composites of high density polyethylene (PE-HD)/ intumescent (IFR)/ organic vermiculite (OVMT) were prepared via direct melt intercalation. The effect of the ratio of melamine polyphosphate (MPP) to pentaerythritol (PER) in the intumescent on composite’s flammability and the effect of the loading of OVMT on the melt intercalation were investigated. It was found that shows that the best wt ratio of MPP/PER was 3:1 at a loading of flame retardant of 30 wt%. The best intercalation result was achieved with 2 wt% OVMT. The limited oxygen index of the PE-HD/IFR/OVMT with a composition of 70/28/2 reached 28.6 %, while the UL94 was V-1 rating. Furthermore, a proper addition of PE-HD-g-MAH to the system could promote the intercalation effect.

Key words: high density polyethylene, intumescent flame retardant, organic vermiculite, melt intercalation, high density polyethylene grafted maleic anhydride