Control of polymer architecture and molecular weight distribution via multi-centered shuttling agent

1. A process for the polymerization of one or more addition polymerizable monomers to form a polymer composition, said process comprising:

contacting an addition polymerizable monomer or mixture of monomers in a reactor or reactor zone with a composition comprising at least one polymerization catalyst and a cocatalyst under polymerization conditions and in the presence of a multi-centered shuttling agent comprising at least a first chain shuttling moiety and a second chain shuttling moiety and having the following formula:

(M′) m A

wherein

M′ is a chain shuttling moiety,

A is a linking group, the linking group being an organic group, and

m is an integer from 2 to 6; and

forming a polymer composition comprising a first polymer free of the second chain shuttling moiety and a second polymer comprising the second chain shuttling moiety.

2. The process according to claim 1 wherein the catalyst comprises a metal complex corresponding to the formula:

wherein:

R 11 is selected from alkyl, cycloalkyl, heteroalkyl, cycloheteroalkyl, aryl, and inertly substituted derivatives thereof containing from 1 to 30 atoms not counting hydrogen or a divalent derivative thereof;

T 1 is a divalent bridging group of from 1 to 41 atoms other than hydrogen, preferably 1 to 20 atoms other than hydrogen, and most preferably a mono- or di-C 1-20 hydrocarbyl substituted methylene or silane group; and

R 12 is a C 5-20 heteroaryl group containing Lewis base functionality, especially a pyridin-2-yl- or substituted pyridin-2-yl group or a divalent derivative thereof;

M 1 is a Group 4 metal, preferably hafnium;

X 1 is an anionic, neutral or dianionic ligand group;

x′ is a number from 0 to 5 indicating the number of such X 1 groups; and bonds, optional bonds and electron donative interactions are represented by lines, dotted lines and arrows respectively, or a metal complex corresponding to the formula:

wherein

M 2 is a metal of Groups 4-10 of the Periodic Table of the elements;

T 2 is a nitrogen, oxygen or phosphorus containing group;

X 2 is halo, hydrocarbyl, or hydrocarbyloxy;

t is one or two;

x″ is a number selected to provide charge balance; and

T 2 and N are linked by a bridging ligand.

3. The process of claim 1 comprising forming a substantially homogeneously polymer composition having a bimodal molecular weight distribution.

4. The process of claim 1 comprising forming a second polymer with a molecular weight at least about two times the molecular weight of the first polymer.

5. The process of claim 1 comprising dividing the multi-centered chain shuttling agent into the first chain shuttling moiety and the second chain shuttling moiety.

6. The process of claim 5 comprising regenerating, after the attaching, a multi-centered chain shuttling agent comprising a polymer segment attached thereto.