Li, Longfei, Zhai, Hong, Wang, Tao, Qiu, Xibo, Qiang, Na, Dong, Peng, Bai, Ying, Peng, Ai-Yun, and Quan, Daping
The ring-opening copolymerization of lactide with carbonate is an available strategy to incorporate reactive groups to the pendent sites of copolymer for further functional modification. A series of random and block copolymers were synthesized from l -lactide (L -LA) and 2-bromomethyl-2-methyltrimethylene carbonate (BMTC) using dodecanol as initiator and stannous octoate as catalyst. The structures of the copolymers were characterized by nuclear magnetic resonance (1H NMR, 13C NMR), gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). The composition of the copolymers can be controlled through changing the feed ratios of n BMTC / n L -LA. It was found the random P(BMTC- co - L LA) copolymers had the semicrystalline characteristic due to the relative long block-like segments of P L LA (L L , P L LA = 5.3–7.3) and the polar interactions from bromo groups, but their crystallinity (X c, P L LA) and melting temperature (T m, P L LA) decreased when the BMTC content increased. The X c, P L LA and T m, P L LA of P(BMTC- b -P L LA) block copolymers were relatively higher than the corresponding random copolymers, and approached gradually to the pure P L LA with the increase of the molecular weight of P L LA block. Finally, the pendent bromo groups of P(BMTC- co - L LA) were easily transformed into azides, which could proceed the azide-alkyne click reaction smoothly and quantitatively at room temperature. Image 1 • Bromine-functionalized poly(carbonate-co-lactide)s were synthesized successfully. • The composition and structure of the copolymers could be controlled precisely. • The random P(BMTC- co - L LA) copolymers exhibited the characteristic of semicrystalline. • Bromine-functionalized poly(carbonate-co-lactide)s could undergo post-polymerization modification easily and efficiently. [ABSTRACT FROM AUTHOR] more...