SÍNTESE DE LÍQUIDOS IÔNICOS BASEADOS EM BIOMOLÉCULAS E SUA APLICAÇÃO NA FORMULAÇÃO DE FILMES DE AMIDO

Abstract

Green Chemistry is related to the sustainable development of chemical activities, both within the industry and academy. Thus, several methodologies have been proposed, as ionic liquids, a class of green solvents composed entirely of ions. As they are composed of charged units, they have low vapor pressure, and therefore are considered non-volatile. They have low melting points, typically below 100 °C, and are highly polar, allowing the dissolution of inorganic and organic substances. An important precursor for the synthesis of bio-ILs is choline, a type of quaternary ammonium salt that is part of B-complex vitamins. These bio-ILs, being environmentally compatible solvents, can be used as additives and/or as plasticizers of films from natural sources instead of polymers of synthetic origin that are not biodegradable. Considering the importance of the development of environmentally adequate techniques for the synthesis of solvents of low toxicity as well as of new materials, the objectives of this work are related to: the development of methodologies for the synthesis of ionic liquids derived from choline hydroxide; incorporation of ionic liquids into films obtained by cassava starch; and characterization of the films by physical and chemical analysis to verify the potential of the biodegradable film associated with the ionic liquid. The methodology for the synthesis of ILs is to react equimolar amounts of choline hydroxide with a series of amino acids and organic acids under constant agitation for six hours at room temperature. For the formulation of the biodegradable film, the casting method was used, which consists in heating the mixture under constant agitation to the gelling temperature (70ºC), for subsequent addition of the plasticizers used in each film. The thickness, water solubility, relative humidity and optical properties of the films were analyzed. In all the analyzes performed, the best behavior was that of the film containing 0.5% of [Ch][Glu] IL as plasticizer. These results are probably due to the potential solubilization of the IL and the interactions with the polymer chains of the starch.