Study on biodegradable polymers: synthesis and characterization of poly(DL-lactic acid-co-l-lysine) random copolymer

Poly(DL-lactic acid-co-l-lysine) (PLAL) random copolymer was obtained by copolymerization of amino acid-N-carboxy anhydride with lactic acid anhydrosulphite in the presence of an initiator. The structures of the poly(DL-lactic acid-co-ε-cbz-l-lysine) and PLAL were characterized by IR, ¹H-NMR, ¹³C-NMR and elemental analysis. Different initiators were used to initiate the ring-opening copolymerization. Good agreement between calculated and actual compositions was observed in most cases when using dibutylzinc as initiator. The solubility of PLAL was discussed.