Method for preparing alpha-olefin/cycloolefin copolymers

A method for preparing a substantially random cyclic olefin copolymer having from about 5 to about 95 mole percent cycloolefin, comprising:

• a) charging a reactor with alpha-olefin and cycloolefin at reaction conditions in the presence of a catalyst system including an ionic catalyst according to the formula:
• ##STR6## wherein A' is a bridging group, which group may serve to restrict rotation of the (C.sub.5 H.sub.5-y-x S.sub.x) and (JS'.sub.z-1-y) groups;
• (C.sub.5 H.sub.5-y-x S.sub.x) is a cyclopentadienyl ring substituted with from zero to four S radicals;
• x is from 0 to 4 denoting the degree of substitution;
• S is a substituent group each S, independently being a radical group which is a hydrocarbyl, substituted-hydrocarbyl, halocarbyl, substituted-halocarbyl, hydrocarbyl-substituted organometalloid, halocarbyl-substituted organometalloid, disubstituted boron, disubstituted nitrogen, substituted chalcogen or halogen radicals, including adjacent S groups joined to form a C.sub.4 to C.sub.20 ring to give a saturated or unsaturated polycyclic cyclopentadienyl ligand;
• M is titanium, zirconium or hafnium;
• X.sub.1 is a hydride radical, hydrocarbyl radical, substituted-hydrocarbyl radical, hydrocarbyl-substituted organometalloid radical or halocarbyl-substituted organometalloid radical which radical may optionally be covalently bonded to both or either M and L or all or any M, S.sub.x or S';
• (JS'.sub.z-1-y) is a heteroatom ligand in which J is an element from Group 15 of the Periodic Table of Elements with a coordination number of 3 or an element from Group 16 with a coordination number of 2;
• S' is a radical group which is a hydrocarbyl, substituted hydrocarbyl, halocarbyl, substituted halocarbyl, hydrocarbyl-substituted organometalloid, or halocarbyl-substituted organometalloid;
• z is the coordination number of the element J;
• y is 1;
• L' is an olefin, diolefin or aryne ligand, or a neutral Lewis base, with w being an integer from 0 to 3 or can also be a second transition metal compound of the same type such that the two metal centers M and M* are bridged by X.sub.1 and X'.sub.1, wherein M* has the same meaning as M and X'.sub.1 has the same meaning as X.sub.1 where such dimeric compounds which are precursors to the cationic portion of the catalyst are represented by the formula:
• ##STR7## B' is a chemically stable, non-nucleophilic anionic complex having a molecular diameter about or greater than 4 angstroms
• d is an integer representing the charge of B';
• and
• b) polymerizing the alpha-olefin and cycloolefin.