Patent ID: 6624261
Filing Date: 2003-09-23
Classification: C08F,C08G

Abstract:
A process for forming a polymer whose polymer architecture is controlled to modify properties of said polymer, said process comprising:free radical polymerizing at a temperature from about 80Â° to 170Â° 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: CH2&boxH;CXY whereinX for monomer A is H and X for monomer B is CH3 or CH2OH; Y is selected from the group consisting of OR, O2CR, halogen, CO2H, COR, CO2R, CN, CONH2, CONHR, CONR2 AND Râ€²; 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, hydroxyl, alkoxy, pimary amino, secondary amino, teritary amino, isocyanato, sulfonic acid and halogen; and the number of carbons in said alkyl groups is from 4 to 12; and Râ€² 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, pimary amino, secondary amino, teritary amino, isocyanato, sulfonic acid substituted and unsubstituted alkyl, substituted and unsubstituted aryl, substituted and unsubstituted olefin and halogen provided when X&boxH;H, Râ€² is not an unsubstituted aryl; 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 80Â° C. toward 170Â° 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: steps for lowering molecular weight of said polymer comprise at least one of said steps I, II, IV and V; steps for effecting a higher degree of vinyl-terminated end groups in said polymer comprise at least one of said steps I, II, IV and V; and steps for increasing branching in said polymer comprise at lest one of steps I, II, IV, and V with step III.