Functional Polylactides Achieved by Iron‐Catalyzed (Co)Polymerization of Different Lactides

Abstract Polylactides are important biodegradable and environment‐friendly materials with monomers being from bio‐sources, being enhanced their applicable properties with higher hydrophilicity as well as more side‐chain groups. Using iron complex catalysts ( Fe1‐Fe8 ), the ring‐opening polymerization (ROP) of four lactides ( L ‐LA, Ph ‐LA, BrPh ‐LA, Bz ‐LA) was individually and efficiently achieved, so were the ring‐open copolymerization (CROP) of L ‐LA with other lactides. For the ROP of L ‐LA, its TOF value reached up to 1.74 × 10 4  h −1 along with obtaining PLA with molecular weight up to 4.28 × 10 4 g· mol −1 ; in contrast, the TOF as 1.01 × 10 3  h −1 was observed for the ROP of Ph‐LA with observing its polymer with highest M n as 7.94 × 10 3  g mol −1 . The CROP of L ‐LA and Ph ‐LA could smoothly proceed whatever their feeding sequences and afforded the random or block copolymer. However, the CROP of L ‐LA with either Bz ‐LA or BrPh ‐LA heavily depends on their feeding sequences, making it necessary to first add L ‐LA and then another comonomer. The microstructures of polymer obtained were characterized by 1 H/ 13 C NMR and MALDI‐TOF. Their architecture of the CROP polymers was significantly affected by the substituents of lactides as well as the feeding sequences.