UV-activated hydrosilylation: A facile approach for synthesis of hyperbranched polycarbosilanes

A facile approach for synthesis of hyperbranched polycarbosilane from AB₂ monomer via UV-activated hydrosilylation is presented in this communication. The polymerization process was monitored using real-time FTIR spectroscopy and the resulting hyperbranched polycarbosilanes were characterized using ¹H-NMR, ¹³C-NMR, ²⁹Si-NMR and SEC/MALLS. It is found that hyperbranched polycarbosilane can be synthesized from methyldiallylsilane via UV-activated hydrosilylation with bis(acetylacetonato) platinum(II) as catalyst. The polymerization activated by UV irradiation was much faster than that under thermal conditions. The similar degree of branching, average number of branch units and the exponent of the Mark- Houwink equation demonstrate that the hyperbranched polycarbosilane synthesized via UV-activated polyhydrosilylation possesses almost the same branching structure as that synthesized via thermal-activated polyhydrosilylation.