Effect of Nanoclay Addition on the Biodegradability and Performance of Starch-Based Nanocomposites as Mulch Films.

The biodegradation and performance of potential agricultural mulch films prepared from native and oxidized corn starch nanocomposites with chitosan-modified bentonite were studied under simulated soil test conditions. Samples were removed at different times and their wet and dry weights were registered. A photographic register of films appearance was also included. Bio-physicochemical changes along biodegradation progress were followed by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TG). Results indicate that all samples degraded in a three step process and that they almost fully degrade by 100 days of testing. The chemical modification of starch and the addition of fillers did not produce significant differences in biodegradation rate. Microbial attack, mainly by fungal microorganisms started at the end of the first week and produced a 50% weight loss in approximately 35 days. Biological assays indicate that germination was negatively affected by proposed starch-based films. [ABSTRACT FROM AUTHOR]