Abstract: Composites were prepared from polypropylene (PP), an intumescent flame retardant(IFR), and maleic anhydride grafted polypropylene (PP-g-MAH) via melt blending. The effect of PP-g-MAH on the flame retardancy and mechanical properties was researched by limiting oxygen index, thermal analysis, etc. The limiting oxygen index of composites reached 30 %, and the burning grading reached to UL 94 V-0, when 5 % of PP-g-MAH was introduced. With increasing contents of PP-g-MAH, the interfacial bonding between flame retardant and PP was enhanced and the tensile, bending strength of composites increased while the impact strength decreased. The carbon residue increased obviously with the addition of PP-g-MAH.

Key words: polypropylene, maleic anhydride grafted polypropylene, compatibility, flame retardancy