Application of Cellulose Nanofibrils Isolated from an Agroindustrial Residue of Peach Palm in Cassava Starch Films

摘要

Cellulose nanofibrils (CNF) isolated from the external sheaths of palm peach (Bactris gasipaes) were evaluated as improvers of several characteristics of cassava starch films. The cellulosic material of 10 to 30 nm diameter was produced by mechanic defibrillation. All films were characterized by scanning electron microscopy, thermal analysis, water vapor permeability (WVP), Fourier transform infrared spectroscopy, physical characterizations (solubility, humidity, water activity, thickness, tensile strength and elongation) and optical analysis. The incorporation of CNF as reinforcement caused changes in all properties analyzed, thus differing from the control film (without cellulosic reinforcement). Physical reinforcement was the main effect observed in films containing CNF, according to the mechanical resistance and permeability analyses. Furthermore, such analyses confirmed the increase in tensile strength in 306% and reduction in 26% of WVP for films containing 5.37% nanofibrils, when compared to the control. Higher opacity was verified as more CNF was added to the filmogenic matrix, as a result of the dispersion of light by nano-sized fibrils. No variations in the thermal profiles occurred in films containing CNF or not. Spectroscopic data revealed a possible crosslinking formation between starch and CNF, which can influence positively the tensile strength of such films.