Polypropylene (PP)／maleic anhydride grafted polypropylene (gPP)／expanded graphite (EG) (gPP／EG =3／2 wt) electrically conductive nanocomposites were prepared via solution intercalation (SI) and its combination with melt mixing named as masterbatch melt mixing (MMM)．Room temperature electrical conductivity (σ) measurements revealed that thc percolation thresholds (φc) of the nanocomposites prepared via SI and MMM were 6 wt％ and 8 wt％ respectively

much lower than those of the composite and the PP／EG control prepared via direct melt mixing(φc=11 wt％ and 12 wt％)．The increment of gPP content (Cg) can elevate the σ of the composites

ex. when its composition became PP／gPP=1／1 wt

the φc of the composites prepared in MMM and DMM decreased to 7 wt％ and 10 wt％

respectively；while for the nanocomposite prepared via MMM

in the case of fixing the EG content of 9 wt％

its σ might jump up more than 7 degress of magnitude as the Cg exceeded 30 wt％．The reasons causing the above differences and phenomena mentioned above were analyzed and elucidated by means of TEM

SEM and OM observations and according to the differences among the preparation methods．