Study on Hydrolysis of Poly(Lactic Acid)/Chitosan/Polyethylene Glycol Nanocomposites in Phosphate Buffer Solution

Poly(lactic acid)/chitosan/polyethylene glycol (PLA/CS/PEG) nanocomposites were prepared by solution method. The content of PEG was 2 – 10 wt. % compared with the weight of PLA. The characterization and morphology of the nanocomposites before and after hydrolysis in phosphate buffer solution were determined by fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry and scanning electron microscopy (SEM). The hydrolysis of PLA/CS/PEG nanocomposites in phosphate buffer solution for different testing time was also investigated. It was clear that the shift of wavenumber for C=O, OH, CH3 groups in FTIR spectra of PLA/CS/PEG nanocomposites before and after hydrolysis. The SEM images of the PLA/CS nanocomposite in the presence of PEG indicated that PEG played a role in the improvement of interaction and dispersion between CS and PLA phases, limitation of permeability of phosphate buffer solution into the structure of the nanocomposites. The obtained results of hydrolysis after 28 testing days showed that the PLA/CS/PEG6 nanocomposite (containing 6 wt. % of PEG) had the lowest weight loss with highest regression coefficient (R2 = 0.9933) in the phosphate buffer solution.