Synthesis and Characterization of Starch Graft Biodegradable Polyester and Polyesteramide by Direct Polycondensation

Starch graft poly(lactic acid-co-glycolic acid) (St-g-PLGA) and poly(lactic acid-co-glycolic acid-co-ϵ-caprolactam) (St-g-PLGC) copolymers were prepared by direct polycondensation from soluble starch, lactic acid, glycolic acid and ϵ-caprolactam in presence of stannous chloride (SnCl2 · 2H2O). The structure of the copolymers was clarified by NMR spectroscopy, and the thermal properties were investigated by differential scanning calorimetry (DSC) and thermogravimetric (TG) analysis. The results indicated that the glass transition temperature (T G ) increased when the contents of ϵ-caprolactam decreased. Moreover, The mechanical properties examination demonstrated that tensile strength and bending strength changed from 32.3 Mpa and 69 Mpa to 24.2 Mpa and 28 Mpa.