Casting and extrusion processes to produce bio-based plastics using cassava starch modified by the dry heat treatment (DHT)

Although the number of studies focused on bio-based plastics is constantly rising, an important challenge to overcome is migrating from casting to extrusion, an industrially scalable method of production. In this work, we studied starch modification by dry heating treatment (DHT) and the production of cassava starch films or sheets, by casting or extrusion processes, respectively. The molecular changes promoted by the DHT process resulted in a new matrix. Furthermore, the slower drying in casting, and the faster drying in extrusion, promoted different molecular arrangements, which affected the material performance. The main results showed that DHT for 4 h in cassava starch produced bio-based plastics with increased mechanical properties and opacity while decreasing water permeability, moisture content and light transmittance. In conclusion, DHT showed to be an interesting alternative to produce biodegradable plastics with potential use in different industries. [Display omitted] •DHT promoted molecular changes resulting in a denser matrix.•For casting or extrusion, different polymeric matrix organization was obtained.•The faster drying in extrusion resulted in the formation of cracks and micro-void.•The slow drying in casting process resulted in an entangled matrix.•For casting or extrusion, DHT produced plastics with enhanced performance.