Synthesis and Characterization of Lactic Acid Based Poly(ester−amide)

The effects of polymerization temperature and the amount of chain extender, 2,2‘-bis(2-oxazoline), on the synthesis of lactic acid based poly(ester−amide) (PEA) were studied. High molecular weight polymer was produced only within a narrow range of polymerization parameters. The highest molecular weights were achieved with the molar ratio of oxazoline/carboxyl end groups being 1.2/1.0 at 200 °C. Poly(ester−amide) was analyzed (GPC, DSC, IR, NMR), and the mechanical properties were measured and compared with those of some biopolymers and commercial thermoplastics. Measured by GPC, the highest molecular weights were over 300 000. The mechanical properties of PEA were good: tensile strength of the high molecular weight polymer was as much as 67 MPa, and the Charpy impact strength was 34 kJ/m2.