A facile and sustainable strategy to construct recyclable paper with enhanced water and oil resistance for eco-friendly food packaging

As a potential substitute for petroleum-based plastics as food packaging material, application of paper is hampered by weak resistance to water and oil. In light of this, paper barrier coating was prepared based on sodium alginate and alkyl ketene dimer. The properties of the obtained SAKD emulsion were investigated and stabilizing mechanism was proposed. Furthermore, SAKD emulsion was applied on paper surface for enhancing barrier properties against both water and oil. After coated, oil resistance KIT was increased from 0 to 8, sizing degree increased by 3977 % and Cobb30 decreased by 66.08 % probably because a more closed structure formed with lower surface energy. Barrier properties to air, water vapor and organic solvents were also strengthened. Additionally, the coating exhibited good stability after folded repeatedly. Furthermore, SAKD coating layer did not negatively affected degradability of paper and the coated paper could be efficiently recycled via a facile treatment, confirming its eco-friendliness. This work demonstrates a sustainable and simple route to prepare paper with good barrier properties and provides the feasibility of developing eco-friendly paper packaging for food based on bio-based materials.