Surface Treatment of Cardboard with Plant and Bacterial Derived Nanocellulose Suspensions

This study investigates powdered cellulose materials, particularly nanocellulose derived from plant and bacterial sources. The nanocellulose was generated by hydrolyz-ing bleached sulphate softwood and hardwood pulp samples with strong acids. The origi-nal materials are present in the product lines of leading Russian pulp and paper companies. The bacterial cellulose was produced under laboratory conditions from Medusomyces gise-vii. The dimensional parameters of the nanocellulose samples were evaluated using electron microscopy, and the degree of polymerization was measured by determining the viscosity of the cellulose solutions in cadoxene. The bleached softwood pulp had a nanocellulose particle length of 80-200 nm, a particle diameter of 80-100 nm, and a degree of polymerization of 60. The bleached hardwood pulp had a particle length of 80-150 nm, a particle diameter of 70- 100 nm, and a degree of polymerization of 50. The bacterial nanocellulose had a particle length of 120-250 nm, a particle diameter of 70-120 nm, and a degree of polymerization of 110. Suspensions of various concentrations (from 1 to 10 %) were prepared from nanocellu-lose samples, which were subsequently used as reinforcing additives in cardboard samples. The additive was applied to the surface in one or two layers. Additives of nanocellulose prepa-rations reduced the breaking length (from 9.6 to 40.4 %) along with an increase in cardboard density (from 6.3 to 23.8 %), tensile rigidity (from 14.0 to 25.0 %) and bursting strength (up to 31.9 %). The best results were obtained by applying a nanocellulose suspension of bleached softwood pulp to the board surface in two layers: a 9.6 % decrease in breaking length was ob-served with an increase in density of 23.8 %, tensile rigidity of 25.0 %, and bursting resistance of 31.9 % relative to the control sample. Therefore, the study showed the possibility of using nanocellulose suspensions derived from plants and bacterial sources by acid hydrolysis for the surface treatment of cardboard.