One-Pot Preparation of 3-Miktoarm Star Terpolymers via "Click Chemistry" and Atom Transfer Nitroxide Radical Coupling Reaction

A new strategy for synthesis of 3-miktoarm star terpolymer without any protection of initiating sites or slow purification steps was reported. The precursors PtBA-N3 (poly(tert-butyl acrylate) with azide end group, TEMPO PEO or TEMPO PCL and PS-alkyne/Br were designed and prepared first, then the star terpolymer composed of PtBA, PS, and PEO. The key precursors PS-alkyne/Br, PtBA-N3, and TEMPO-PEO or TEMPO-PCL were prepared and characterized fully by GPC, 'H NMR, MALDI-TOF, and FTIR. The one-pot procedure was carried out in presence of CuBr/Cu/PMDETA at 70°C for 24 h, the click chemistry between azide group and alkyne functional group, and ATNRC reaction between TEMPO group and bromine group were realized simultaneously. Thermal transitions of the 3 miktoarm star terpolymer and its corresponding linear analogue were determined by DSC. The results indicated the occurrences of click chemistry and ATNRC reaction, and the formation of star terpolymers.