Poly(lactic acid) (PLA) was modified using a simple reactive blending method, where a low molecular weight poly(ethylene glycol) acrylate (PEGA) was blended with PLA in the presence of a radical initiator. To examine the initiation effect on the modification of PLA, various amounts of radical initiator (between 0 and 1.5 %) were added to the PLA/PEG acrylate mixture. The modified PLAs (PLMs) were characterized by gel permeation chromatography, Fourier transform infrared spectroscopy, wide-angle X-ray diffraction, and solvent extraction. The properties of the PLMs were investigated using tensile testing, differential scanning calorimetry, thermogravimetric analysis, scanning electron microscopy, and hydrolytic degradable analysis. The PEGA significantly influenced the molecular structure and properties of the modified PLA. The glass transition temperature of the PLMs was decreased by approximately 15 A degrees C (for PLM15) from 59.3 A degrees C of PLA, whereas their toughness increased considerably compared to PLA. In addition, PEG acrylate facilitates hydrolytic degradation, even after radical polymerization by reactive blending.