Potential Agricultural Mulch Films Based on Native and Phosphorylated Corn Starch With and Without Surface Functionalization with Chitosan

In order to overcome the problem that represents the use of agricultural polyethylene-mulch films a bio-based and biodegradable alternative based on starch was proposed and evaluated. Starch phosphorylation followed by surface functionalization with chitosan was carried out in films made from corn (Zea mays) starch. The potential agricultural mulch films were manufactured from native and phosphorylated corn starch. The modification of the starch was made by means of two methodologies: wet chemistry by means of aqueous suspension method followed by extrusion and reactive extrusion in a single step. All film systems done were then obtained by thermo-molding. Thermal, barrier, mechanical and morphological characterization was carried out in order to evaluate the potential of these materials as agricultural mulches. The results suggested that the modification made on the starch and surface functionalization were not adequate to achieve the recommended properties for the agricultural usage. Phosphorylated starch films, however, showed adequate barrier and thermal properties, despite that their mechanical behavior still needs to be improved.