Fabrication of water/oil-resistant paper by nanocellulose stabilized Pickering emulsion and chitosan

Abstract

Developing plastic/fluorine/silicon-free and degradable water/oil-resistant coatings for paper-based packaging materials to replace disposable plastic products is a very effective way to solve the problem of ‘white pollution’ or microplastics pollution. A novel water/oil-resistant coating was developed by alkyl ketene dimer (AKD)-based Pickering emulsion and chitosan in this work. Cellulose nanofibrils (CNF) were used as a stabilizing solid for AKD emulsion, with the addition of chitosan as an oil-resistance agent. The coating provides excellent hydrophobicity, water/oil resistance as well as good barrier properties. The water contact angle was as high as 130° and the minimum Cobb60 value was 5.7 g/m2, which was attributed to the hydrophobicity of AKD. In addition, the kit rating reached maximum 12/12 at coating weight of 8.26 g/m2 and the water vapor transmittance rate (WVTR) was reduced to 153.4 g/(m2⋅day) at the coating weight of 10.50 g/m2. The tensile strength of the paper was increased from 28.1 to 43.6 MPa after coating. Overall, this coating can effectively improve the performance of paper-based materials, which may play an important role in the process of replacing disposable plastic packaging with paper-based materials.