Mechanical Behavior and High Formability of Palm Leaf Materials

The proliferation of single‐use plastics has stimulated interest in sustainable material substitutes with sufficient ductility and structural integrity. Herein, the mechanical behavior and high formability of the leaf sheath from a representative palm species—Areca catechu—and its immense potential for manufacturing of eco‐friendly food packaging are reported on. Using microstructural analyses, such as X‐ray micro‐computed tomography (μCT), electron microscopy, and optical profilometry, under different loading conditions, it is shown that this leaf can accommodate forming strains as large as 200%, similar to ductile metals. The sheath deformation response is highly sensitive to hydration, with up to 400% increase in forming strain. The embodied energy for leaf products is four to five orders smaller than for plastic or paper products. The results establish the microstructure basis for the high formability and the contours of a forming limit diagram that delineates product shapes that can be formed in a single step from this plant material.