Two kinds of highly active catalysts composed of TiCl 4 SiO 2 MgCl 2 AlR 3(SM) and Mg RX TiCl 4 AlR 3(MG 2) for the gas phase polymerization of ethylene were studied The mass friction of Ti

the surface area of catalysts and catalytic activity in SM and MG 2 are 2%～3%

6%～7% by mass

105～120

70～85 m 2/g

the mass of PE catalyzed by 1 g of Ti in one hour is 5 0～5 7

1 8～2 0 kg

respectively.Kinetic curve of ethylene polymerization with SM is decadent and that with MG 2 is steady.The influence of catalytic properties on gas phase polymerization of ethylene were discussed.The morphology of catalyst particles of SM and MG 2 is studied by SEM and image analysis The average value of particle diameter( )

the ratio between major axis and minor axis of the particle( d l /d s) and the ratio between big and little particle diameter( d max / d min ) of the SM MG 2 catalyst are 31 μm

33 μm

1 402

1 524 and 4 1

7 0

respectively. The corresponding values

d l /d s

d max / d min of polymerization product for SM and MG 2 catalyst are 247 μm

263 μm

1 295

1 540 and 4 6

9 0

respectively The results indicate that the quality of SM catalyst is good