ATRP promoted by ULIS was studied for its effectiveness for making block copolymers in a practical way. A macroinitiator derived from polystyrene was synthesized by allowing the polymerization to near quantitative conversions. The macroinitiator was capable of initiating polymerization of MMA by making use of the tridentate ligand available as part of the ?�chain end and without addition of any external ligand. Moderately high conversion of monomers was achieved in a reasonable time. Block copolymerization was also achieved without any ligand as well as metal salt although the conversion was moderately low. ULIS was also found to be suitable for making high molecular weight polymers with moderately high polydispersities. The polydispersity was dependent on the solvent employed for the polymerization and likely due to the high viscosity of the reaction medium even at 50% conversion or below. Owing to the fact that the polymerization was conducted using CuBr in ppm quantities, the polymers precipitated in a non-solvent were colorless and thus did not require any other cumbersome purification steps as is commonly employed for polymers obtained by ATRP. Since ULIS is active in water based polymerizations as well, it may be possible to make high molecular weight polymers with acceptable polydispersities by employing a suitable dispersion medium during polymerization.

Preparation of block copolymers and high molecular weight polymers by ATRP using Unimolecular Ligand Initiator (ULIS) dual functional systems

244th National Meeting (2012)

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