Biobased nanocomposite coating of paper for packaging

Abstract

Biobased coating material is required to replace synthetic polymer-based paper coating material for a safe and clean environment. The study aimed to investigate the use of biobased nanocomposites as a coating material for paper. The biobased nanocomposite was prepared using nanocellulose, sodium alginate (SA), and bio-synthesized silver nanoparticles (AgNPs). Nanocrystalline cellulose (NCC) was produced through acid hydrolysis, followed by fractionation. The average size of the crystals was 15 nm in width and 125 nm in length. AgNPs were prepared by the reduction of AgNO3 with lignin. The synthesis of silver nanoparticles was confirmed by UV–visible and FTIR spectroscopy. SA-NCC composite coating improved the barrier and strength properties of paper. The paper with composite coating demonstrated a 29.11 % increase in tensile index in the cross direction, 20.82 % increase in the machine direction, and 77.89 % improvement in burst index at a coating weight of 1.68 g/m2. The composite-coated paper showed better air barrier and lower water absorption characteristics than sodium alginate-coated paper. The incorporation of AgNPs in the coating mixture introduced the antimicrobial activity of the paper as well.