Copper Wire-Catalyzed RDRP in Nonpolar Media as a Route to Ultrahigh Molecular Weight Organic-Inorganic Hybrid Polymers

摘要

Controlled synthesis of high-molecular weight (MW) organic-inorganic hybrid polymers based on polyhedral oligomeric silsesquioxane (POSS) monomers has previously proved difficult to achieve by reversible-deactivation radical polymerization methods. Here, this problem is tackled by employing a rarely used combination of Cu(0) catalysis and nonpolar solvents to polymerize a POSS-methacrylate monomer, ~iBuPOSSMA. It is revealed that chain transfer to solvent plays a dominant role in this system as only benzene and not toluene allows for synthesis of low dispersity, ultrahigh MW products (up to 3 500 000). Importantly, the process is characterized by very low amounts (units of ppm) of copper released into the polymerization mixture, leading to products with no discoloration. Finally, benzene use is also shown to be beneficial for copper bromide-catalyzed polymerization of ~iBuPOSSMA, affording polymers with moderate MWs and extremely low dispersities (down to 1.06).