Inhibitorhydroquinone(HQ)wasaddedtothereactionsystemtopreparepolypropylene/polystyrene(PP/PS)blendpelletswithoutPSonthesurfaceduringdiffusionandsubsequentpolymerizationofstyreneinisotacticpolypropylenepellets.TheeffectsoftheamountofHQondiametricaldistributionofPS,surfacemorphologyofthepelletsandphasemorphologyinsidetheblendpelletswereinvestigated.