Cellulose nanofibers from sugarcane bagasse and their application in starch‐based packaging films

Abstract Starch‐based biocomposites exhibit great potential as an alternative to fossil‐based materials. This work focused on investigating the properties of the starch‐based biocomposite reinforced by cellulose nanofibers derived from sugarcane bagasse (SCB). The sodium hydroxide (NaOH) concentration was varied from 4%, 8%, and 12% wt/vol for the SCB extraction process. The obtained nanofibers, respectively called SCBNF4, SCBNF8, and SCBNF12, were characterized by various techniques prior to being incorporated into modified starch (MS). The effects of the type and amount of SCBNF on the mechanical properties, thermal behavior, optical transparency, and moisture absorption of the biocomposite films were examined. All SCBNF samples had a cellulose type I structure with a diameter on the nanometer scale, regardless of the NaOH concentration. The SCBNF's diameter decreased, whereas the crystallinity index increased with increasing NaOH concentration. When incorporated into MS, the higher SCBNF loading resulted in enhancements of mechanical properties and resistance to moisture absorption with the sacrifice of optical transparency. The biocomposite filled with SCBNF12 exhibited better overall performance at a certain filler loading due to the greater filler‐polymer interaction. The benefits of greater strength, light weight, and eco‐friendliness of the developed biocomposites make them suitable for many applications, including packaging. Highlights Diameter and crystallinity index of SCBNF were governed by NaOH concentration. Adding SCBNF to MS greatly improved the biocomposite's mechanical properties. SCBNF12 showed the highest biocomposite's overall performance. The maximum strength was achieved at 1 phr of SCBNFs. The addition of SCBNFs reduced water and moisture absorption.