Microstructure and Mechanical Performance of Molongó Wood: Unveiling an Unexplored Amazonian Timber

This study investigates the microstructure and mechanical properties of the Amazonian Malouetia Tamaquarina (Aubl.) (Apocynaceae), commonly known as Molongó wood. In this paper we provide the first assessment of its potential for use in structural sandwich panels. Microstructural characterisation is performed using scanning electron microscopy (SEM), X-ray computed tomography (XCT), and mercury intrusion porosimetry (MIP). The wood exhibits a highly porous cellular structure with porosity values up to 87.8%. The cell wall thickness is observed to range from 2.6 to 10 µm. Mechanical testing is employed to assess the response in tensile, compressive, flexural, and Charpy impact loading. A strong anisotropy is observed, where the longitudinal direction exhibits the highest strength and stiffness. Tensile and flexural moduli reach 0.85 GPa and 0.82 GPa, respectively. In contrast, the impact resistance is highest in the transverse direction, due to pit deformation. The lignin content of the wood is 27.1%, in line with lightweight angiosperm woods. The results suggest that Molongó wood combines low density and favourable specific properties, indicating potential for lightweight, sustainable structures.