Bacterial Cellulose Coatings for Improved Air and Moisture Barrier Properties of Kraft Paper

ABSTRACT This work presents an investigation on bacterial cellulose (BC) as coatings over kraft paper for improvement in the barrier properties. The 100‐m‐thick papers were coated with 3 g/m of BC by wet casting. Comparisons of surface characteristics were made with kraft paper coated with chitosan, another widely used biodegradable polymer. Electron micrographs revealed that these coatings provided a conformal filling of the asperities on the surface and reduced the roughness. Coating with BC made the kraft paper more lyophobic. The water vapor transmission rate (WVTR) and air permeability of the kraft paper were reduced by g/m/day and m/Pa s, upon coating with BC. These barrier properties and changes in surface wettability were either quantitatively similar or better than those when coated with chitosan and achieved with a thin coating (2 m). Both these key characteristics were achieved while maintaining nearly the same chemical, mechanical and thermal characteristics of the coated and uncoated papers. These results suggest that BC can be explored as a biopolymer coating to improve the barrier properties of paper for packaging applications.