Synthesis of heteroarm star-branched polymers by means of anionic living polymerization in conjunction with functional group transformation

The synthesis of new heteroarm A(2)B(4), A(2)B(delta), A(2)B(12), and ABC(4) star-branched polymers with well-defined structures is described. Our method for these star polymer synthesis involves the three reaction steps: The first step is to prepare the polystyrenes with a definite number of methoxymethylphenyl groups as prepolymers. The methoxymethylphenyl groups thus introduced are quantitatively transformed into chloromethylphenyl groups by treating with BCl3, in the second reaction step. In the third step, poly isoprenyllithium is reacted to link with the chlorinated prepolymers to afford the desired heteroarm star polymers. The resulting heteroarm star polymers were finally isolated in 80-85% by SEC fractionation. Their well-defined and controlled structures were demonstrated by SEC,H-1 NMR: and light scattering measurements.