PLA coated paper containing active inorganic nanoparticles: Material characterization and fate of nanoparticles in the paper recycling process

Abstract

For paper and paperboard packaging, recyclability plays an important role in conserving the resources and reducing the environmental impacts. Therefore, when it comes to the nano-enabled paper packaging material, the recyclability issue should be properly addressed. This study represents our first report on the fate of nanomaterials in paper recycling process. The packaging material of concern is a PLA (Polylactic Acid) coated paper incorporating zinc oxide nanoparticles in the coating layer. The material was characterised and assessed in a lab-scale paper recycling line. The recyclability test was based on a method adapted from ATICELCA MC501-13, which enabled to recover over 99% of the solids material. The mass balance result indicates that 86–91% zinc oxide nanoparticles ended up in the rejected material stream, mostly embedded within the polymer coating; whereas 7–16% nanoparticles ended up in the accepted material stream. Besides, the tensile strength of the recycled handsheets suggests that the nano-enabled coating had no negative impacts on the recovered fibre quality.