Development of starch-based films using a biofriendly ionic liquid as plasticizer

Nowadays, starch has been used as matrix for biodegradable films, since in the presence of a plasticizer (water and polyols) and elevated temperature, a process known as "gelatinization" occurs, resulting in disruption of the granular semi-crystalline structure. ln this context, lonic Liquids (lls) have been investigated as alternative plasticizers, due to their exceptional properties, such as negligible vapor pressure and plasticizing ability. 1·3 ln this work, we present [Ch]Bz IL as a new plasticizer agent for the development of film formulations. The IL was obtained by a neutralization reaction between benzoic acid and cholinium ch loride and, then, used in the film formulation through the casting method , which consists in the heating of an aqueous solution of starch 3%. For comparison, we prepared a film containing only glycerol 1 % as plasticizer (Table 1 ). Films characterization were performed in a Mi noita digital colori meter and the data were used in the equation 1. Thickness was measured in a digital micrometer. The data showed a slight increase in the film thickness in both glycerol concentrations (0.5 and 1.0%), when 0.5% of IL was employed as plasticizer. Generally, the starch-based fi lm formulations lead to a high opacity grade due to the plasticizer addition. However, we observed that the IL addition resulted on a lower opacity percentage when compared with the glycerol film, due to the compati bility between the IL and the starch polymeric chains. Thus, we presented herein a novel film formulation based on ionic liquids.