Effect of airflow presence during the manufacturing of biodegradable films from polymers with different structural conformation

The preparation method to obtain biodegradable films has an important effect on their performance. The drying of film-forming solutions is a very important step usually ignored during the manufacturing of biodegradable films. The objective of this study was to evaluate the effect of the drying process (natural convection or forced convection) on the functional properties of films from polymers with different structure. The film-forming solutions were dried using airflow (forced convection) and no air circulation (natural convection). Films from polyvinyl alcohol (PVOH, with linear structure) and polymers with different degree of branching (potato starch and high amylose corn starch) were evaluated. Films dried in forced convection showed important changes in the water adsorption, mechanical and thermal properties. Drying under forced convection could have promoted the formation of intermolecular bonds during the rearrangement of the polymer chains resulting in films with greater barrier to water vapor and better mechanical performance.