Properties of poly(ethylene glycol)-grafted poly(lactic acid) plasticized with poly(ethylene glycol)

Poly(lactic acid) (PLA) was grafted by a poly(ethylene glycol) (PEG) acrylate through reactive blending method and consecutively blended with a low molecular weight PEG plasticizer. The grafted PEG on the PLA was confirmed by nuclear magnetic resonance (NMR) and Fourier transform infrared (FTIR) spectroscopy. Properties of the plasticized PLAs (PLEs), prepared by blending the PEG-grafted PLA (PLG) with various contents of the PEG plasticizer, were investigated using tensile testing, wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), dynamic mechanical analysis (DMA), and hydrolytic degradation analysis. The tensile strength of the plasticized PLA (PLE09) was decreased by 48%, from 51.1 to 26.7 MPa, while its elongation at break increased by 24 times, from 6.5% to 158%. Thermal properties and biodegradability were also greatly influenced by the hydrophilic PEG modifier.