Copolymerization of azide-containing carbonate with lactide and post functionalization

The intention of this work was to study the polymerization of a cyclic carbonate monomer bearing one azido group, i.e. 2-(azidemethyl)-2-methyltrimethylene carbonate (AMTC), to disclose the characteristics of the resulted polymers and to explore the feasibility of their post-functionalization with alkynyl compounds via Click reaction. Homopolymerization of AMTC was first studied using stannous octoate (Sn(Oct) 2 ) as the catalyst and dodecanol as the initiator, which had the characteristic of active polymerization. Copolymerization of AMTC with L -lactide ( L -LA) was then investigated under the same reaction condition, in which L- LA exhibited higher reactivity than AMTC. The reactivity of AMTC was low not only in its homopolymerization but also in its copolymerization with L -LA, while the conversion of AMTC increased by extending the reaction time. The copolymer P(AMTC-co- L LA) (PLAC) had the semicrystalline characteristic due to the relative long block-like segments of P L LA ( L ¯ L = 35.5 ). Based on these results, copolymerization of AMTC with L -LA using PEG 4K as macroinitiator was further studied to afford PLAC-PEG-PLAC copolymers. The copolymerization could be well controlled at low ratio of [M] 0 /[I] 0 (from 10 to 50) and molar fraction of AMTC in feed ( f AMTC = 0.1, 0.2). The pendent azido groups of PLAC-PEG-PLAC could undergo post-functionalization through azide-alkyne click reaction easily and efficiently.