Preparation of multi-allylic dendronized polymers via atom-transfer radical polymerization

Atom-transfer radical polymerization (ATRP) was investigated to polymerize a styrene monomer carrying carbosilane dendrons with 6 terminal allyl branches. Polymers with a monomodal molar mass distribution and low polydispersity have been produced, while by comparison the free-radical polymerization technique led to chain transfer early in the polymerization. Steric effect brought by the dendrons result in a slow polymerization rate, leading to an apparent saturation of the degree of polymerization. By pushing up the polymerization conditions (eg. increase of temperature or concentration), interchain couplings started to take place, most likely from reactions at the allyl branches. These results are very similar to the ones previously reported for the anionic polymerization of this same multi-allylic dendronized monomer.