Effect of PCL Nanocomposite Coatings on the Recyclability of Paperboard Packaging

When it comes to the disposal of paperboard and cardboard packaging waste to reduce their environmental impact, recycling is one of the most desirable options. With innovations and development of biopolymer coatings and their application in packaging materials, new paper-based packaging solutions are expected on the market. Besides evaluating their mechanical and barrier properties, it is essential to assess their environmental impact. Therefore, this study investigated the impact of biodegradable polycaprolactone (PCL) polymer coating, as well as PCL modified with SiO2, Al2O3, and ZnO nanoparticles, on the recycling behavior of paperboard. The coating samples were prepared by dissolving PCL polymer in ethyl acetate and nanoparticle dispersion. Paperboard (230 g/m2) was printed by offset printing process and then coated with PCL and PCL nanocomposite coatings. Recycling was performed under controlled laboratory conditions following a standardized method. Deinkability was assessed by evaluating the optical properties and using an image analysis system. From the obtained results, it can be concluded that the use of PCL coatings and PCL coating modified with SiO2, Al2O3, and ZnO nanoparticles do not significantly impact the optical properties of the recycled pulp, thereby not restricting the implementation in paperboard production and waste management.