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.
通过聚合二烯单体(如
丁二烯)形成功能聚合物的第一聚合物嵌段,从而形成具有至少一个能够形成稳定自由基的取代基的功能聚合物。第一聚合物嵌段的重量平均分子量小于 15 万。聚合
乙烯基芳香族单体(如
苯乙烯),至少形成功能聚合物的第二聚合物嵌段。将共聚物与提供稳定自由基的化合物接触,形成官能聚合物。通过添加足够的
乙烯基芳香族单体,可使低分子量的功能性橡胶聚合物在环境温度下进行加工,同时保持溶液粘度,以适合
乙烯基芳香族单体的后续自由基催化。