Recyclable oil resistant paper with enhanced water resistance based on alkyl ketene dimer modified sodium alginate

Abstract Sustainable coatings exhibit potential in enhancing oil resistance of packaging paper. Alkyl ketone dimer (AKD) was used to esterify sodium alginate (SA) to prepare water and oil resistant agent SAD. As SAD was coated on paper, it reduced the surface energy and blocked the fiber pores of paper, thus improving the barrier performance of paper. The oil resistance grade can reach grade 6 at coating amount of 2.13 ± 0.26 g/m 2 , which is qualified for food packaging. The coated paper also showed good barrier to hot castor oil. Resistance to organic solvent and water were also enhanced with initial water contact angle (WCA) increased to 69.2°. Compared with base paper, SAD coated paper had better mechanical properties and more importantly, coated paper can be effectively recycled to achieve green recycling.