Abstract: A long chain branched polypropylene（LCBPP）was prepared with polypropylene（PP） as a raw material in the melting process. The LCBPP was added to following blends: PP/polystyrene（PS）, PP/styrene-acrylonitrile block copolymer（SAN）, and PP/polyethylene terephthalate（PET）.Fourier transform infrared（FTIR） and extensional rheology were adopted to characterize the LCBPP. According to the SEM,LCBPP exhibited a good compatibilizing effect on the blends system in which the dispersed phase was a polar component. After adding 5 %LCBPP into the PP/SAN（70/30）and PP/PET（70/30）systems separately, the size of the dispersed phase significantly refined and dispersed evenly. However, the compatibilizing effect of LCBPP was not better than that of polypropylene grafted with maleic anhydride（PP-g-MAH）.The compatibility of PP/PS system was improved only slightly by using LCBPP.

Key words: long chain branched polyprolylene, styrene-axrylonitrile block copolymer, polyethylene terephthalate, polystyrene, compatibilizer