Development of strong and high-barrier food packaging films from cyclic-anhydride modified bacterial cellulose

Using non-substituted and long-chain substituted cyclic anhydrides as the esterifying agents and dimethyl sulfoxide as the solvent, high water vapor/oxygen/bacterial resistant, mechanically/thermally strong, and biodegradable bacterial cellulose (BC) films have been fabricated according to a simple, efficient, and low-pollution surface modification protocol. The anhydride loading, reaction time and characterization in terms of the esterification degree, crystallinity, microstructures, transparency, barrier resistance, mechanical and thermal properties of the films, and fruit preservation tests were investigated. Modification with 10 wt% dodecenyl succinic anhydride (DSA) increased the dry tensile strength (TS) of the film to 124 MPa and the wet TS to 81 MPa in 30 min. Modification with 10 wt% octadecenyl succinic anhydride (OSA) reduced the water vapor permeability of the film by 84% and yielded the highest antimicrobial effect on the film surface. The film modified with 3 wt% of maleic anhydride (MA) had the strongest oxygen barrier and preserved strawberries most effectively. These films were totally biodegraded in soil within one month and exhibit strong potential to be bio-based and biodegradable food packaging materials.