摘要
Despite the extraordinary success has been achieved in metal catalyst-promoted stereoselective ring-opening polymerization（ROP） of rac-lactide（rac-LA）, well-controlled stereoselective rac-LA ROP by organic catalyst still remains a scientific challenge. Here we report our investigations into organocatalytic stereoselective ROP of rac-LA by utilizing novel bulky chiral and achiral N-heterocyclic carbenes（NHC）, 1,3-bis-（1′-naphthylethyl）imidazolin-2-ylidene. The effect of polymerization conditions（e.g. solvent, temperature, alcohol initiator） on ROP behavior by these bulky NHCs has been fully studied, leading to the formation of isotactic-rich stereoblock polylactide（Pi = 0.81） under optimized conditions with high activity（Conv. = 98% in 30 min） and narrow molecular weight dispersity（D = 1.05）.
Despite the extraordinary success has been achieved in metal catalyst-promoted stereoselective ring-opening polymerization（ROP） of rac-lactide（rac-LA）, well-controlled stereoselective rac-LA ROP by organic catalyst still remains a scientific challenge. Here we report our investigations into organocatalytic stereoselective ROP of rac-LA by utilizing novel bulky chiral and achiral N-heterocyclic carbenes（NHC）, 1,3-bis-（1′-naphthylethyl）imidazolin-2-ylidene. The effect of polymerization conditions（e.g. solvent, temperature, alcohol initiator） on ROP behavior by these bulky NHCs has been fully studied, leading to the formation of isotactic-rich stereoblock polylactide（Pi = 0.81） under optimized conditions with high activity（Conv. = 98% in 30 min） and narrow molecular weight dispersity（D = 1.05）.
基金
financially supported by the Science and Technology Commission of Shanghai Municipality(No.17JC1401200)
