Fabrication of coconut dregs residue derived nano-cellulose film for food packaging

•Production of cellulose film from coconut dregs is reported for the first time.•Hydrochloric acid concentration and ultrasonication affect the mechanical properties and the transparency of the film produced.•The film produced can maintain the freshness of grapes better than conventional plastic. To replace conventional plastic as food packaging, several studies related to the preparation of cellulose films from various types of biomass have been reported. However, there have been no reports regarding the use of coconut dregs residue as source of cellulose for the fabrication of cellulose films. This is the first report on the fabrication of cellulose film from coconut dregs under various conditions. The purpose of this work was to investigate the effect of hydrochloric acid, and ultrasonication during the isolation process of cellulose from coconut dregs on the characteristic of cellulose film produced. Hydrochloric acid was used in the hydrolysis process and the concentrations used were 3 M, 5 M, and 7 M. The ultrasonication process was performed after the bleaching process of cellulose isolation. Cellulose films were prepared from ultrasonicated isolated cellulose particles prepared with different hydrochloric acid concentrations and compared with cellulose films obtained from isolated cellulose without the ultrasonication process. Results showed the higher hydrochloric acid concentration the lower particle size of cellulose produced. The cellulose particle size decreased after ultrasonication treatment and cellulose obtained using hydrochloric acid 7 M became nano-size cellulose particles after the ultrasonication process. These results influence the film properties obtained from these cellulose particles, where the lower the particle size the more transparent the film produced. The most transparent film was produced from cellulose particles isolated using hydrochloric acid 7 M in combination with the ultrasonication process. Furthermore, hydrochloric acid concentration and ultrasonication also influenced the tensile strength, crystallinity, and thermal stability of the films.