Ferric ethoxide．ferric n—propoxide．ferric iso—propoxide and ferric n—butoxide were used as initiators respectively for bulk ring-opening polymerization of lactides．The effects of initiator content and polymerization time on the polymerization were investigated．It was showed that these ferric alkoxides were efficient initiators for the ring—opening polymerization of lactides with higher than 90％ of monomer conversions polymerized at 130℃ for 36 h．Maximum molecular weights were achieved at 1／1000 of initiator／monomer mole ratio for the four ferric alkoxides and then decreased gradually with increasing the amount of initiator and prolonging polymerization time．Poly(D；L-lactide)and pely(L-lactide)withthe maxium viscosity-arerage molecularweights(Mv)of 7．28×104 and 19．00×104 respectively were synthesized by using ferric ethoxide as initiator．It was found that the ligands of the ferric alkoxides had significant influence on the molecular weight and molecular weigth distribution of the polymerization products．With increasing the volume of the ligands of the ferric alkoxides

the molecular weight decreased and the molecular weight distribution broadened．1H and 13C-NMR analyses indicated that the ferric alkoxides studied here had no racemization on the ring-opening polymerization of L—lactide

but exhibited isotactie stereoselectivity addition on the ring—opening polymerization of D

L-lactide．Intermolecular tranestefificafion took place during polymerization of D．L-lactide for the four ferric alkoxides as evidenced by the results of MALDI-TOF MS analysis．and quantitative evaluations by 13C-NMR were made for the four initiation systems．However

no regularity of ligands of the ferric alkoxleds on both of isotactic stereoselectivity addition and intemaolecular tranesterification was found due to incomplete resolution of the13C-NMR spectra．