Abstract: PP-g-MAH modified PP/nano-clay composite was prepared on a twin-screw extruder.Effect of the compatibilizcr, PP-g-MnH，on the sag resistance of the composite was studied by XRD analysis and sag resistance testing. Experimental results show that the compatilizcr properties and dosages have certain influences on the intercalation structure and the sag resistance of the
composite. When the compatilizcr with lower melt flow rate and lower grafting rate was used，the composite exhibited excellent sag resistance. The layer spacing of the different intercalated structure of the composite was related to the sag resistance，there was optimal layer spacing. While
the layer space of the clay is 2. 90一3. 00 nm, the sag resistance of the PP/nano-clay composite
reached its highest value.

Key words: polypropylene, nano-clay, compatibilizcr, polypropylene-graft-malcic anhydride, intercalation structure, sag resistance