Identifying microstructural properties of paper

Abstract

AbstractNowadays, paper is no longer used only as a writing and printing material. In addition to its use as a packaging material, it is an important substitute for products that were previously made from carbon‐based resources. Due to its high recycling potential, paper will very likely become even more important in the future. Therefore, it is essential to know the structure and performance and to know how to influence them depending on the application. One key aspect is the distribution of the fibers in the paper. It has a great influence on the load‐bearing capacity of different directions and on the strength of the product. Forty samples of a three‐layer paperboard were examined for their fiber distribution. For this purpose, X‐ray microcomputed tomography scans were performed, which provided data on the entire thickness of the paper in a nondestructive manner. The fiber orientations were described using orientation tensors. The distribution of the principal direction was analyzed and approximated with parametric probability density functions chosen on the basis of statistical tests. It was first proved that the fibers are mainly aligned in the plane. Furthermore, variations in the fiber distributions within a paper roll were found, with a larger scatter visible in the center of the paper roll.