Patent ID: 7521486

Claim:
A method for making a branched polymer composition, comprising: (a) reacting monomers into a plurality of oligomer molecules, each oligomer molecule in said plurality of oligomer molecules having a first end and a second end; and (b) irradiating said oligomer molecules with radiation sufficient for energizing at least one atom at an interim location between said first end and said second end on each oligomer molecule to form activated oligomer molecules so that (1) the energized atom directly separates from the activated oligomer molecule at said interim location, and (2) a free radical site remains on each activated oligomer molecule at said interim location; (c) wherein a plurality of said activated oligomer molecules bond at said free radical sites at their respective interim locations, forming branched polymer portions; (d) said branched polymer composition consists essentially of polymer molecules having said branched polymer portions; and (e) said branched polymer composition comprises polymer selected from the group consisting of fluoroelastomer, acrylic elastomer, ethylene/acrylic elastomer, nitrile rubber, polyurethane, silicone rubber, ethylene-propylene rubber, thermoplastic elastomer derived from fluoroelastomeric oligomer in said oligomer molecules, thermoplastic elastomer derived from acrylic elastomeric oligomer in said oligomer molecules, thermoplastic elastomer derived from ethylene/acrylic elastomeric oligomer in said oligomer molecules, thermoplastic elastomer derived from nitrile rubber oligomer in said oligomer molecules, thermoplastic elastomer derived from polyurethane oligomer in said oligomer molecules, thermoplastic elastomer derived from silicone rubber oligomer in said oligomer molecules, and thermoplastic elastomer derived from ethylene-propylene rubber oligomer in said oligomer molecules.