Biodegradable Blends Prepared from Polycaprolactone and Poly(glutamic acid): Structure, Thermal Properties, and Biodegradability

Biodegradable polycaprolactone/poly(glutamic acid) (PCL/PGA) blends were prepared by a melt blending method. Additionally, acrylic acid-grafted polycaprolactone (PCL-g-AA) was studied as an alternative to PCL. The samples were characterized using Fourier transform infrared (FTIR) spectroscopy, nuclear magnetic resonance (NMR), differential scanning calorimetry (DSC), an Instron mechanical tester, and scanning electron microscopy (SEM). Because of poor compatibility between PCL and PGA, the mechanical properties of PCL/PGA blends were worse than of PCL alone. The PCL-g-AA/PGA blends had obviously improved mechanical properties over PCL/PGA ones, and the former provided a plateau tensile strength at break when the PGA content was up to 20 wt%. Biodegradation tests of blends were also conducted in a soil environment; the results showed that the mass of blends declined by about the PGA content within 4 weeks.