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

Polylactides are important biodegradable and environment‐friendly materials with monomers being from biosources, being enhanced their applicable properties with the 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) were 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 1.74×104 h‐1 along with obtaining PLA with molecular weight up to 4.28×104 g·mol‐1; in contrast, the TOF as 1.01× 103 h‐1 was observed for the ROP of Ph‐LA with observing its polymer with highest Mn as 7.94×103 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 were heavily depending their feeding sequences, being necessary of firstly adding L‐LA then another comonomer. The microstructures of polymer obtained were characterized by 1H/13C NMR and MALDI‐TOF. Their architectures of the CROP polymers were significantly affected by the substituents of lactides as well as the feeding sequences.