Fundamental study on barrier coating of paper using cationic cellulose nanofibrils

Abstract

In this study, never-sized base paper was used to investigate layer-by-layer multilay-ered barrier coating with cationic and anionic cellulose nanofibrils (CNFs). The cationic and anionic CNFs were both prepared by isolating hardwood bleached kraft pulp (HwBKP) using a microgrinder. Surface modification of the HwBKP with polydiallyldimethylammo-nium chloride (Poly-DADMAC) was undertaken to create cationic CNFs before microgri-nding. The barrier coating was applied with a rod coater, and the coating weight and air permeability of the barrier-coated paper were measured. Coverage by the CNFs was evaluated via scanning-electron-microscope images of the barrier-coated paper. As the pass number of micro-grinding increased, the air permeability of the paper barrier-coated with cationic and anionic CNFs increased. As the number of coating layers increased, the coating weight increased, and coverage of the barrier-coated paper improved. The coating weight and air permeability of the paper barrier-coated with both cationic and anionic CNFs exhibited higher values than those of paper barrier-coated with only anionic CNFs for the same number of coating layers. Consequently, high air permeability and high coverage of paper are possible if both cationic and anionic CNFs are utilized as barrier coatings. ? 2020 Korean Technical Assoc. of the Pulp and Paper Industry. All rights reserved.