Patent ID: 7148297

Claim:
A polymer made in accordance with a process for forming such polymer whose polymer architecture is controlled to modify properties of said polymer, said process comprising: free radical polymerizing at a temperature from about 80° to 170° C. and in the presence of a cobalt-containing chain transfer agent and a free radical initiator at least two unsaturated monomers A and B defined by the formula: CH 2 ═CXY wherein X for monomer A is H and X for monomer B is CH 3 or CH 2 OH; Y is selected from the group consisting of OR, Q 2 CR, halogen, CO 2 H, COR, CO 2 R, CN, CONH 2 , CONHR, CONR 2 AND R′; R is selected from the group consisting of substituted and unsubstituted alkyl, substituted and unsubstituted aryl, substituted and unsubstituted heteroaryl, substituted and unsubstituted aralkyl, substituted and unsubstituted alkaryl, and substituted and unsubstituted organosilyl, the substituents being the same or different and selected from the group consisting of carboxylic acid, carboxylic ester, epoxy, bydroxyl, alkoxy, primary amino, secondary amino, tertiary amino, isocyanato, sulfonic acid and halogen; and the number of carbons in said alkyl groups is from 1 to 12; and R′ is selected from the aromatic group consisting of substituted and unsubstituted aryl, substituted and unsubstituted heteroaryl, the substituents being the same or different and selected from the group consisting of carboxylic acid, carboxylic ester, epoxy, hydroxyl, alkoxy, primary amino, secondary amino, tertiary amino, isocyanato, sulfonic acid substituted and unsubstituted alkyl, substituted and unsubstituted aryl, substituted and unsubstituted olefin and halogen; wherein the improvement comprises controlling said polymer architecture by: introducing said monomers A and B at a molar ratio of A:B in the range of about 1,000:1 to 2:1 and by employing steps selected from the group consisting of: I decreasing the molar ratio of A:B from about 1,000:1 toward 2:1; II increasing the temperature from above 80° C. toward 170° C.; III increasing the conversion of said monomers to said polymer toward 100% from less than about 50%; IV choosing monomers A and B such that the ratio of the chain transfer constant of A:B is decreased to below 1; V increasing the concentration of cobalt chain transfer agent; and a combination thereof; whereby: said molecular weight of said polymer is lowered by employing at least one of said steps I, IV, and V; a higher degree of said vinyl-terminated end groups in said polymer is effected by employing at least one of said steps I, IV, and V; and said branching in said polymer is increased by employing at least one of steps I, II, IV, and V with step III.