Preparation of Chitosan‐g‐Poly(l‐Lactic Acid) Copolymer

Abstract

ABSTRACT Although poly ( l ‐lactic acid) (PLLA) is used as tissue engineering scaffold to implant in vivo, secondary inflammation will be induced by the lactic acid enrichment in short period during the PLLA implant degradation. To dissolve the problem, the chitosan (CS), a typical polyaminosaccharide is introduced to neutralize the acetic acid when the scaffold is degraded in vivo. First, the active amino groups of CS are protected by excess phthalic anhydride. Then, the ring‐opening polymerization of lactide onto phthaloyl‐protected CS could be performed without the addition of a catalyst. Finally, the product is deprotected by hydrazine hydrate to give chitosan‐ g ‐poly ( l ‐lactic acid) (CS‐ g ‐PLLA). The structure of CS‐ g ‐PLLA copolymer is characterized by infrared spectrum and 1 H nuclear magnetic resonance. When CS is introduced on PLLA, the solution of the degraded copolymer ceased to be acidic. In addition, CS‐ g ‐PLLA shows excellent solubility in some organic solvent for the easier tissue engineering scaffold preparation.