Ethylene polymerization using (RCp)(2)ZrCl2/MAO catalytic system

This paper describes ethylene polymerization using four kinds of zirconocen e with different substitutionary groups in Cp ring as catalysts and alumino xane as cocatalyst. Their polymerization activities and M-eta, of resultant polyethylene were compared. It was found basically that in T-p = 70 degree sC and Al/Zr = 1000, polymerization activities were of the following order: A(2) > B-2 > A(1) > B-1 [A(1): (CH2=CH-CH2-CH2-Cp)(2)ZrCl2; B-1: (CH2=CH-C H2-CH2-CH2-Cp)(2)ZrCl2; A(2;) (CH2=C(CH3)-CH2-Cp)(2)ZrCl2(;) B-2: (CH3(CH3) -C=CH-CH2-Cp)(2)ZrCl2]. Polymerization activities were affected greatly by polymerization conditions. The influences of catalyst concentrations on pol ymerization activities were discussed. The possible effect mechanism of dif ferent substitutionary groups in Cp ring on polymerization activities was i nvestigated, (C) 2000 Elsevier Science Ltd. All rights reserved.