High Barrier, Biodegradable Nanocomposite Films Based on Clay-Coated and Chemically Modified Gum Kondagogu
Abhilash Venkateshaiah, Renee L. Timmins, Elmar Sehl, Stanislaw Waclawek, Miroslav ?Cerník, Vinod V. T. Padil and Seema Agarwal
Macromol. Mater. Eng., 2022, 2200008, DOI: 10.1002/mame.202200008
Lately, environmentally benign packaging materials with biodegradability, flexibility, and high barrier properties are sought after as a substitute for conventional plastic packaging materials due to increasing plastic pollution and microplastics in the environment. Although natural polymers can be sustainable alternatives to petro-sourced, non-biodegradable plastics, they suffer from the poor barrier and mechanical properties. In this study, a mechanically stable, biodegradable film of tree gum kondagogu with remarkable barrier properties is fabricated. The introduction of spray-coated, waterborne, large-aspect ratio sodium-hectorite dispersion on tree-gum films ensured very high barrier properties even at high relative humidity conditions (oxygen transmission rate (OTR) ˜1.7 cm3 m-2 day-1 bar-1 at 75% relative humidity). The coating not only decreases gas permeability through the films but also minimizes the sensitivity of performance to humidity levels. The clay-coated nanocomposite films outperformed various commercial polymers and are comparable to high-performance packaging films in terms of oxygen barrier properties. Further, the coating improved the mechanical properties of the films rendering them a prospective packaging material. These biodegradable, high-barrier and mechanically robust films are a promising advance in the field of sustainable packaging.