| abstract |
A functional polymer having at least one substituent capable of forming a stable free radical is formed by polymerizing a diene monomer, such as butadiene, to form a first polymer block of the functional polymer. The first polymer block has a weight average molecular weight of less than 150,000. A vinyl aromatic monomer, such as styrene, is polymerized to form at least a second polymer block of the functional polymer. The copolymer is contacted with a stable free radical providing compound to form the functional polymer. By adding sufficient vinyl aromatic monomer, a low molecular weight functional rubber polymer can be rendered processable at ambient temperatures, while maintaining a solution viscosity which is suited to subsequent free radical catalyzation of vinyl aromatic monomers. |