Abstract: To improve the intrinsic safety of pure PP with increasing flame retardancy and antistatic properties, a novel halogen-free intumescent flame retardant polypropylene composites (ZIF-8/PP) were prepared using ZIF-8 type zeolite imidazolate framework material, ammonium polyphosphate (APP) and pentaerythritol (PER). The effects of ZIF-8 on properties of polypropylene were studied with methods such as oxygen index, mechanical test, thermal gravimetric analysis, and resistance test. The results indicate that the addition of ZIF-8 can improve effectively the flame retardancy and antistatic properties of pure PP, with slight decreasing of the mechanical property, that when the mass fraction of ZIF-8 is 3%, the following properties of ZIF-8/PP expressed: the oxygen index reaches 28%, the surface resistivity decrease to 10⁸ Ω·cm (resulting in the transition from insulator to anti-static body), and the tensile strength of ZIF-8/PP is 21.2 MPa, and that ZIF-8 can increase the composites' amount of residual carbon, and the compact carbon layer with foam morphology formed in the melt surface inhibiting the flue gas, and improve the composites' thermal stability.

Key words: polypropylene(PP), zeolite, intumescent flame retardant, oxygen index, thermal stability, composites