Influence on the addition of starch to bio-based films of Polylactic acid

MALBOS, LUCIANA; MANFREDI, L. B.; IGLESIAS MONTES, M.L.; CYRAS, V. P.

Mar del Plata

Jornada; Jornadas INVESTIGAR UNMDP; 2020

Jornadas INVESTIGAR UNMDP

In recent years, polymers obtained from natural and biodegradable resources have attracted great interest due to the decrease in the reserve of fossil fuels and the growing concern about the accumulation of waste. Therefore, biodegradable polymers have been the subject of numerous investigations, in order to reduce the environmental impact. In this work it is proposed the development of biodegradable coatings from bio-based polymer blends: starch and polylactic acid (PLA). In this way, the synergy between the good properties of each polymer would allow to obtain a new advanced material. On the one hand, PLA would provide good mechanical properties while, on the other hand, starch would offer good thermal properties and lower cost. Native and acetylated starch were plasticized with 30 wt.% of glycerol. Polymeric films with PLA/Starch and PLA/Acetiled-Starch ratio of 70/30 were obtained by melt mixing (T profile of 140?180°C and 50 rpm) and compression molding (190ºC and 70 kg/cm2). Pure PLA and the final films were characterized by Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). The addition of native and acetylated starch to PLA produced an increase in the crystallinity of the films, which would indicate that starch acts as a nucleating agent. Finally, PLA-based materials with higher thermal resistance could be obtained as a result of the addition of starch and the consequent higher crystallinity degree.