Many-arm star polymers synthesized using chlorosilane linking agents:: Their structural quality concerning arm number and polydispersity

A series of polybutadiene star polymers were produced by coupling living poly(butadienyl)lithium with dendritic chlorosilane linking agents. The theoretical arm numbers of the stars covered the range from 4 to 64, and the arm molecular weight was kept short with dM(n(arm)) = 10(3). MALDI-TOF MS and H-1 NMR spectroscopy were used to characterize the dendritic linking agents. The low M-n(arm) also allowed the investigation of the star polymers by MALDI-TOF MS in addition to the classical characterization techniques. It was found that up to the star with 16 arms the structural quality with respect to functionality and polydispersity coincides with the theoretical values. In the ease of the star polymers with theoretically 32 and 64 arms, the average functionalities found for the chlorosilane dendrimers were 31 and 60, respectively, and the polydispersities were considerably smaller than 1.01. The corresponding star polymers had average arm numbers of approximately 29 and 54, along with molecular weight distributions of 1.01 and 1.02, respectively.