Using Cellulose Nanofibril from Sugarcane Bagasse as an Eco-Friendly Ductile Reinforcement in Starch Films for Packaging

Attempts have been made to replace conventional plastics in food packaging with biodegradable materials as a promising alternative because they are natural, renewable, and low-cost. This study aimed to develop biodegradable and resistant films from cellulose nanofibrils (CNFs) from sugarcane bagasse when used as reinforcement in starch films. Sugarcane bagasse pulps were subjected to alkaline treatment, with the residual lignin remaining. Part of the material was subjected to a bleaching process with H2O2. The pulps were subjected to the mechanical fibrillation process, and unbleached and bleached CNFs were produced. Percentages of 10%, 20%, 30%, and 50% CNF were added to a solution containing 2.5% starch (m/m) solids to make the films. The addition of unbleached CNF promoted an average increase in the tensile strength and Young’s modulus values, especially for films with higher percentages of CNF (30% and 50%). The contact angle values increased with the CNF concentration, with all films being classified as hydrophobic (>90°), except for the films with 30% and 50% unbleached CNF. The 50% unbleached and bleached CNF samples showed low water vapor permeability (2.17 g.mm/Kpa−1 day−1 m2), indicating a good vapor barrier. Although the influence of residual lignin on the test results was not identified for the other samples, treatments with 50% CNF of sugarcane bagasse (unbleached or bleached) should be highlighted among the properties evaluated for reinforcing the structure and improving the barrier properties of cassava starch-based films. Furthermore, this study proposes using sugarcane bagasse, which is a waste widely available in Brazil, placing the study in line with three Sustainable Development Goals (SDGs).