Biodegradation of modified starch/poly lactic acid nanocomposite in soil

In this work, the effect of lactic acid grafted starch nanocrystals (g-SNCs) on the rate of the soil burial degradation of Poly (lactic acid) was studied using the weight loss measurement (wt.%), X-ray Photo Electron Spectroscopy (XPS), Fourier-Transform Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC). The weight loss results demonstrated that the degradation rate of PLA accelerated by adding g-SNCs nanoparticles. The FT-IR analysis showed that the intensities of C-O, C=O, and C-H bond of PLA/g-SNCs are higher than neat PLA that has declined further by increasing soil burial time. The XPS displayed that the atomic percentage of the O-C=O in PLA/g-SNCs was reduced more than neat PLA after soil burial. In addition, the variation of the O/C ratio has been controlled by g-SNCs nanoparticles degradation due to the higher hydrolysis tendency of g-SNCs. Also, the DSC analysis depicted that the glass transition temperature and degree of crystallinity of PLA/g-SNCs nanocomposites obviously decreased and increased respectively despite a slight variation for neat PLA. Regarding all the above facts, it was hypothesized that the soil burial-induced degradation rate of PLA can be significantly augmented in the presence of g-SNCs.