Successive synthesis of well-defined many arm star-branched polymers by an iterative methodology using a specially designed 1,1-diphenylethylene

The synthesis of well-defined regular and asymmetric star-branched polymers having as many as 63 arms, each of similar or different composition, is described. This synthesis has been achieved by developing a new, iterative methodology using a specially designed functionalized reagent, 3,5-bis(3-(4-(1-phenylethenyl)phenyl) propoxy) benzyl bromide ( 5). This reagent is capable of introducing two 1,1-diphenylethylene (DPE) functions via one reaction site. The methodology involves only two sets of reactions for entire iterative reaction sequence: ( a) an addition reaction of living anionic polymer(s) to DPE-chain-functionalized polymer to link polymer chain( s) and (b) an in situ substitution reaction of 5 with 1,1-diphenylalkylanions newly generated after the addition reaction. Two DPE functions are introduced per one anion. With this methodology, well-defined 3-, 7-,15-, and 31-arm followed by 63-arm regular star-branched polystyrenes as well as 3-arm AB(2), 7-arm AB(2)C(4) ,and 15-arm AB(2)C(4)D(8), followed by 31-arm AB(2)C(4)D(8)E(16) asymmetric stars were successively synthesized. The A, B, C, D, and E segments were polystyrene, poly(alpha-methylstyrene), poly(4-methylstyrene), poly(4-methoxystyrene), and poly(4-trimethylsilylstyrene) segments, respectively. All of the analytical results with H-1 NMR, SEC, SLS, and RALLS measurements revealed a high degree of structural and compositional homogeneity in each of all the stars synthesized in this study.