PREPARATIONANDCHARACTERIZATIONOFSPHERICALPP/PBALLOYSWITHMgCl2-SUPPORTEDZIEGLER-NATTACATALYST

<正>Polypropylene（PP）/polybutene-1（PB） alloys within reactor were prepared by MgCl2-supported Ziegler-Natta catalyst with sequential two-stage polymerization technology.First,propylene homo-polymerizations were carried out to form isotactic polypropylene（iPP） particles containing active catalyst.Then,butene-1 was subsequently polymerized to form polybutene-1 phase inside the iPP particles.Finally,iPP/PB alloys with spherical shape and adjustable PB content were synthesized.The catalytic activity and catalytic stereospecificity of the Z-N catalyst in the two-stage polymerization process are discussed.The composition and physical properties of the PP alloys were characterized by FT-IR,13C-NMR,SEM,DSC and XRD.It was found that the in-reactor PP alloys are mainly composed of PP and PB with a little amount of poly（butene-co -propylene） random copolymers and poly（butene-block-propylene） block copolymers.SEM measurements verified that the PB phases with size in the range of 300-400 nm dispersed in the PP matrix uniformly.The incorporation of PB upon the PP matrix affects the properties of final products greatly.