Filmes nanoestruturados a base de quitosana oriunda da casca de camarão reforçados com nanofibrilas de celulose extraídas do resíduo de açaí

Abstract

In the Amazon region, there are numerous subproducts from extractivism economic (e.g., fibers from açai fruit and chitosan by shrimp shells) that have been showed a great potential for sustainable products development. Considering this scenario, cellulose nanofibrils (CNFs) obtained from açaí processing residues can be used as reinforcement in polymeric matrices such as chitosan applied as polymer matrix, in order to guarantee improvements on mechanical, thermal and barrier properties of nanocomposites. This work aims to investigate the effect of adding CNFs from açaí residues on physical and mechanical properties of chitosan-based nanocomposite films from two Amazon shrimp species: M. amazonicum (QMA) and M. carcinus (QMC). Chitosan was isolated from these two species through the chemical method and CNF was obtained by mechanical defibrillation of the açaí stone fibers. The pure and composite formulations were prepared using the casting technique and characterized in relation to water vapor permeability rate (WVPR), water vapor permeability (WVP), water solubility (WS), water absorption (WA). Film surfaces were also analyzed using atomic force microscopy (AFM) and scanning electron microscopy (SEM). Chitosan was characterized as a function of the degree of deacetylation (DD) and the yield of the quantified processes. The results showed that the chitosan obtained from the shells of M. amazonicum presented a DD higher than that obtained from M. carcinus. Neat CNF films showed a surface with greater roughness and less homogeneous compared to neat QMA and QMC films, as indicated by AFM images. The nanostructured films exhibited an improvement on physical properties (WVPR, WVP, WS and WA) after the CNF addition. On the other hand, the increase in the concentration of the reinforcement tended to form agglomerates.