Liu, Shaofeng Li, Huaike Zhao, Na Li, Zhibo Stereoselective Ring-Opening Polymerization of <i>rac</i>-Lactide Using Organocatalytic Cyclic Trimeric Phosphazene Base Phosphazene base is an important organocatalyst in polymer chemistry owing to its high activity and versatility. In this contribution, we demonstrate that cyclic trimeric phosphazene base (<b>CTPB</b>) can catalyze stereoselective ring-opening polymerization (ROP) of <i>rac</i>-lactide (<i>rac</i>-LA) to produce isotactic stereoblock PLA (<i>P</i><sub>i</sub> up to 0.93). The polymerizations are highly controlled, as evidenced by linear relationship between molecular weights (MW) and monomer conversions and the narrow dispersity (<i>Đ</i> = <i>M</i><sub>w</sub>/<i>M</i><sub>n</sub>) of the resulted polymers with high fidelity of end groups. The investigations on polymerization parameters show that the tacticity of produced PLA depends on the polymerization temperatures and solvents, while the kinetic studies reveal a faster rate for ROP of l-LA as compared to <i>rac</i>-LA under same conditions. Based on these results, the chain end control mechanism is proposed to explain the production of isotactic stereoblock PLA from <i>rac</i>-LA by an achiral catalyst. chain end control mechanism;rac;polymerization temperatures;CTPB;P i;polymer chemistry;MW;end groups;ROP;monomer conversions;achiral catalyst;polymerization parameters show;cyclic trimeric phosphazene base;Organocatalytic Cyclic Trimeric Phosphazene Base Phosphazene base;catalyze stereoselective ring-opening polymerization;Stereoselective Ring-Opening Polymerization;isotactic stereoblock PLA 2018-05-16
    https://acs.figshare.com/articles/journal_contribution/Stereoselective_Ring-Opening_Polymerization_of_i_rac_i_-Lactide_Using_Organocatalytic_Cyclic_Trimeric_Phosphazene_Base/6275606
10.1021/acsmacrolett.8b00353.s001