Controlled synthesis of functionalized polysiloxanes with dendritic structure

摘要

General characteristic of the structure and the ways of a synthesis of dendrtic polymers, especially known methods of the synthesis of dedritic polysiloxanes (Schemes A and B) was presented. A new method of the synthesis of functionalized dendritic polysiloxanes, developed by Authors's team, was discussed. Anionic polymerization and ring opening copolymerization of cyclotrisiloxanes were used to obtain "tailor made" living polysiloxanes containing vinyl side groups and active propagation center-silano-late group-at one end of a chain. Termination of this polymer on the poly-functional core containing chlorosilyl groups leads to the grafting of polyxiloxane on the core (Scheme E). Branched polysiloxane, after transformation of vinyl groups to chlorosilyl ones, becomes a core for grafting of the next generation of polysiloxane branches (Scheme H). At the least step of the synthesis, to the living polymer also another functional groups, e.g.-CH_2CH_2PPh_2 or -(CH_2)_3Cl, are introduced. The method presented makes possible the synthesis of dendritic polymer of controlled density as well as location of the branches and functional groups. The own research works focused on the synthesis of dendritic polysiloxanes chemically bounded to the silica gel surface (Scheme I) were also shortly discussed.