Structural changes of cassava starch and polylactic acid films submitted to biodegradation process.

Polylactic acid (PLA) and starch are compounds used in the manufacture of packaging to replace petroleum products as biodegradable and environmentally friendly materials. This study evaluated the structure and surface of a film manufactured by extrusion from cassava starch and PLA, which underwent a biodegradation process under compost conditions following the guidelines of ISO 4855-2:2007. Samples were taken every week for one month to perform Fourier Transform Infrared Spectroscopy (FT-IR) tests to identify functional groups on film, and High-Resolution Optical Microscopy (HROM) and Scanning Electron Microscopy (SEM) tests, from these techniques Structural changes in the film were evidenced. The addition of PLA increases the carbonyl index. The introduction of anhydrous malic acid (MA) in PLA/TPS mixtures may lead to an increase in the carbonyl index, The TPS/PLA composite film was framed in the three phases of biodegradation: disintegration, fragmentation, and mineralization. In week 4 a reduction in film size was observed with a thinning of the film with fractures that produced fragmentation and disintegration.