Synthesis and properties of poly (L-lactide)-poly(ethylene glycol) multiblock copolymers

A series of multiblock copolymers of PLLA-PEG(PLE) with high molecular weight were synthesized by coupling PLLA-PEG-PLLA triblock copolymers with succinic anhydride in the presence of (N, N-dimethylamino) pyridine(DMAP) and dicyclohexylcarbodimide (DCC). The results of the viscometry measurement, GPC and ¹H-NMR, elucidated that multiblock PLE copolymers with high content of short PEG segments (M_n = 2000) had been successfully obtained. The crystallinity of the copolymers was investigated by X-ray diffraction. Mechanical testing showed that multiblock copolymers had relatively high tensile strength and large elongation. In a word, the measurements showed that the multiblock PLE copolymers had high content of short PEG segments (M_n = 2000), high molecular weight (M_w ∼ 100,000), excellent hydrophilicity and mechanical properties. The results of cells cultured on the multiblock PLE copolymer indicated that it might be suitable to be utilized as cell scaffold for tissue engineering.