As per the research published in ACS Omega, substituting plastic layers in takeout containers with paper could improve sustainability. Through mechanical testing and computer simulations, researchers explored paper-aluminium laminate designs that maintain durability and functionality. Zarei's team initially created two types of paper-aluminium laminates – A machine direction laminate (MD) and a cross-direction laminate (CD).
A machine-direction (MD) laminate, with aluminium and paper fibres aligned parallel to the loading direction (with the grain), and a cross-direction (CD) laminate, with fibres oriented perpendicular to the loading direction (against the grain). Researchers tested the tensile strength of these MD and CD laminates against conventional polyethylene-aluminium laminates by gradually applying force to samples with laboratory machines. Additionally, they developed a digital model, validated by tensile strength data, to simulate these stretching tests and reliably predict the material's behaviour under various conditions.
In the tests, the polyethylene-aluminium laminate demonstrated greater stretchability before breaking compared to both paper-aluminium laminates. Among the paper options, the MD paper laminate stretched further but developed cracks along the grain faster than the CD paper. Using simulations with MD, CD, and a mixed MD/CD paper on their digital model, the researchers predicted that combining aluminium with a paper layer containing both MD and CD fibres could achieve mechanical properties close to traditional polyethylene-aluminium laminates.
While the MD/CD paper-aluminium laminate has not yet been produced in the lab, this research provides valuable insights for packaging engineers aiming to develop sustainable materials with performance comparable to conventional options.
Source: Al Circle
