Abstract: Hydroxyl terminated lactic acid prepolymer （PLEG） was synthesized from poly ethylene glycol (PEG) and lactic acid, which was further condensed with maletic anhydride (MA) forming MPLA. The effect of reaction conditions (composition, temperature, reaction time, etc.) on the molecular weight (MW) of the product was studied via orthogonal design experiments. The maximum MW about 60000 was obtained at a weight ratio of MA/PLEG of 1/15, reacted at 130 C for 15 h. The mechanical properties, hydrophilicity, and in vitro degradation behavior of MPLA were studied. Modified with MA, MPLA exhibited better tensile strength, modulus, elongation at break, and hydrophilicity than PLEG. In addition, MPLA showed good in vitro degradation behavior, with the degradation rate related to the content of maletic anhydride.

Key words: maletic anhydride, lactic acid prepolymer, biodegradation, polycondensation, modification