Synthesis and Properties of Poly(Ester Urethane)s Consisting of Poly(L-Lactic Acid) and Poly(Ethylene Succinate) Segments

An aliphatic polyester based poly(ester urethane) (PEU) consisting of poly(L-lactic acid) and poly(ethylene succinate) was successfully prepared via chain-extension reaction of poly(L-lactic acid)-diol (PLLA-OH) and poly(ethylene succinate)-diol (PES-OH) using 1,6-hexamethlyene diisocyanate (HDI) as a chain extender. PLLA-OH was obtained by direct polycondensation of L-lactic acid in the presence of 1,4-butanediol. PES-OH was synthesized by condensation polymerization of succinic acid with excessive ethylene glycol. The structures and molecular weights of PLLA-OH, PES-OH, and PEUs were characterized by proton nuclear magnetic resonance (H-1 NMR), Fourier transform infrared (FTIR), and gel permeation chromatography (GPC). The PEUs were further studied by the means of thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and tensile testing. The data of GPC analysis indicated that high molecular weights for example more than 200 000 g.mol(-1) were easily synthesized through chain-extension reaction. The PEUs synthesized with high molecular weight and excellent tensile properties could find some applications in biomaterials and environmental friendly materials.