Highly efficient synthesis and characterization of multiarm and miktoarm star-long-branched polymers via click chemistry

Abstract

Two series of 3–12 multiarm star polymers of butadiene and styrene (S-PB and S-PS) with high M_n of arms (≥20 kg mol⁻¹) and narrow PDI (≤1.04) were synthesized via click chemistry between azide-terminated polymers and multialkynyl organic molecules. Comparing to the previous report, higher yield of coupling reaction (≥85%) was obtained along with increasing arm number and molecular weight of the single-arm polymer (over 4–5 times that before). In particular, 96.1%, as the highest efficiency, occurred in the synthesis of 12-arm star PB. The 4-miktoarm star copolymer of butadiene and styrene was also synthesized with high yield (95.1%), high arm M_n and narrow PDI (1.04) by one pot synthesis using click reaction between two different linear polymers (PS-N₃ and PB-N₃) and a 4-arm core. All the star polymers were characterized by GPC-MALLS-Viscosity-DRI. These multiarm star polymers exhibit morphologies from random coil to hard sphere depending on the arm-number of the star polymers. Intrinsic viscosity appeared the maximum with increasing arm numbers in star PB and PS, in which PB-4arm and PS-6arm had the highest values, respectively.