Introduction of Functional Groups into Divergent Starburst Polysiloxanes

Functional groups, such as dimethylamino and hydroxy groups, were introduced to the periphery position of the third generation starburst polysiloxane (G3) prepared by the divergent method. Phenylsilane unit of the second generation polymer (G2-Ph) was converted to the diethylaminosilane unit (G2-DEA) via the corresponding bromosilane (G2-Br) generated by the reaction of the phenylsilane with bromine. Next, G2-DEA was reacted with the building block possessing one silanol and two dimethylamino, or one silanol and two benzyloxy unit, yielding the starburst polysiloxanes possessing 24 dimethylamino groups (G3-DMA) or benzyloxy groups (G3-Bz) at the periphery position. The latter polymer was converted to G3-OH which had 24 hydroxy groups. The IR, 1H NMR, and GPC measurements supported a successful introduction of these functional groups. The solubility of the starburst polysiloxanes was remarkably affected by the functional groups.