A poly(lactic acid)\|based block copolymer was synthesized in order to increase the cell ahesion of poly(lactic acid).Lys(Z)NCA was first synthesized from Nε-carbobenzyloxy-L-lysine and triphosgene in THF.Diblock copolymers aminoended poly(Nε-carbobonzyloxy-L-lysine)-b-poly(lactic acid) were synthesized in DMF in the condition that amino-ended PLA was used as initiator.Amphiphilic triblock copolymers poly(L-lactic acid)-b-poly(Nεcarbobonzyloxy-L-lysine)-b-poly(ethylene glycol) were synthesized in CHCl3 in the condition that amino-ended poly(lactic acid)-b-poly(Nε-carbobenzyloxy-L-lysine) was acylationed by carboxyl-terminal poly(ethylene glyco1).The block copolymers were characterized via IR(infrared spectroscopy)

1H-NMR(nuclear magnetic resonance)

GPC(gel permeation chromatography) and TEM(transmission electron micrographs).The results revealed that triblock copolymers with controlled Mn and narrow molecular weight distribution (Mw/Mn =1.07) were synthesized

the acylation reaction yield was more than 70%.Poly(ethylene glyco1) and Nε-carbobenzyloxy-L-lysine were introduced into the main chain of poly(lactic acid)

and a kind of ideal bioabsorbable polymer materials were obtained.