One-pot synthesis of ABC type triblock copolymers via a combination of "Click Chemistry" and atom transfer nitroxide radical coupling chemistry

A new strategy for one-pot synthesis of ABC type triblock copolymers via a combination of "click chemistry" and atom transfer nitroxide radical coupling (ATNRC) reaction was suggested, and poly(tert-butyl acrylate)-block-polystyrene-block-poly(ethylene oxide) (PtBA-PS-PEO) and poly(tert-butyl acrylate)-block-polystyrene-block-poly(epsilon-caprolactone) (PtBA-PS-PCL) were successfully prepared by this method. The precursors with predetermined number-average molecular weight and low polydispersity indices, such as PS with alpha-alkyne and omega-bromine end groups, PtBA with azide end group, PEO and PCL with a 2,2,6,6-tetramethylpiperidine-1-oxyl end group, were directly prepared by living polymerization technique using the compounds with corresponding functional groups as initiators, and no further modifications of the end groups were needed, except PtBA-N-3. The coupling reaction between precursors was carded out in the CuBr/N,N,N',N '',N ''-pentamethyldiethylenetriamine system with high efficiencies. The obtained polymers were characterized by FT-IR, H-1 NMR, differential scanning calorimetry, and gel permeation chromatography in detail.