COPOLYMERIZATION OF ETHYLENE WITH 1-OCTENE CATALYZED BY HAFNOCENE DIAMIDE

Copolymerization of ethylene with 1 octene is reported based on metallocene, rac \|C 2H 4(Ind) 2Hf(NMe 2) 2 (1) (Ind=η 5\|indenyl) and (CH 3) 2C(Fluo)(Cp)ZrMe 2 (2) (Cp=η 5\|cyclopentadienyl,Fluo=η 5\|fluorienyl).The result shows that the copolymerization rate increases with the increase of comonomer molar ratio ([O]/[E]).Further increase of [O]/[E] reduces copolymerization rate.The activity of 1/Al(\%i\%Bu) 2/[Ph 3C][B(C 6F 5) 4](3) is much higher than that of 2/MAO.System 1/Al( \%i\% Bu) 2/3 also shows higher incorporation ability of 1\|octene into copolymer than that of 2/MAO.The values of the product r E× r O are below 1 for all the resulting copolymer,which correspond to random copolymer structures with a more alternating structure.The melting point( T m),crystallinity ( X C),intrinsic viscosity ([η]) and density ( D ) of the 1\|octene/ethylene copolymers decreased markedly with an increase in the 1\|octene content,regardless of the type of catalytic system.High comonomer contents of the products show clearly amorphous behavior.All the copolymers show melting within a broad temperature range,duplicate peaks or with shoulder.The copolymers produced by 1/Al( i Bu) 2H/3 have much higher molecular weight than that of 2/MAO,and have a wider range of density from 0 965 to 0 84 g/cm 3.