Preparo de filmes nanocompósitos biopoliméricos reforçados com nanofibras a partir da casca do cupuaçu (Theobroma grandiforum Schum)

Abstract

Synthetic polymers take many years to degrade in the environment, making them efficient materials for the environment, currently, there is a worldwide interest in sustainable and biodegradable plastic materials. Biopolymers are an alternative, they are materials of natural origin and renewable sources. Among several natural polymers, we have chitosan, derived from chitin, and cellulose acetate, derived from cellulose, which show to be promising in the formation of filmogenic solutions. In addition, the removal of nanocellulose from biomass and its introduction into polymeric matrices has been shown to be an alternative as a reinforcement, as it promotes mechanical resistance. In this context, the present work aimed to produce polymeric blends composed of cellulose acetate and chitosan and reinforced with nanocellulose extracted from cupuaçu bark. The mixtures were obtained by the casting technique, where 1%, 2%, 4% and 6% cellulose acetate solutions were prepared, as well as chitosan solutions in 0.5%, 1%, 2% and 4% acetic acid. The films were characterized in terms of optical, structural, morphological and mechanical properties. The films with the best transmittance results were with 4% and 6% cellulose acetate concentrations and with 2% and 4% chitosan concentrations, where the AC6Q20 and AC6Q40 films obtained the best transparency and were selected for the addition of nanocellulose. The incorporation of the nanomaterial in the polymeric matrix of the films altered the mechanical properties of the material, in addition, the materials were pores in the polymeric matrix, being an indicator of the presence of nanocomposite. Visually, the films formed by the mixtures of chitosan and acetate formed resistant and transparent films, however the addition of nanocellulose enriched with turbidity, due to the use of PSS for its solubility in aqueous solutions. The mixtures of chitosan cellulose acetate (AC6Q20 and AC6Q40) obtained in this study have potential for use in plastic films, and may contribute to the use of smaller amounts of chemical preservatives in food and reduce the environmental impact caused by non-biodegradable packaging.