Effects of wood microfiber chemical treatment on mechanical properties of wood/polypropylene composites moulded by injection process

The technological option for developing composite materials appears as a sustainable alternative for the manufacturing industries, allowing the design of new materials with improved physical-mechanical properties. Composites materials formed by treated microfibers on recycled and pigmented polypropylene matrix were produced in a single screw extruder and moulded by injection as test specimens for tensile, flexion, and impact tests, subsequently, the mechanical, thermal and morphological characterization of the composites was carried out. The chemical treatments tested in this work have the purpose of removing oils, waxes, and lignins which cover the natural fibre cell wall external surface. In this way, the treatment will promote an increase in the maximum stress and the modulus of elasticity in tension and bending. Thus, the results obtained show that the composites with eucalyptus microfibers treated with NaClO achieved greater strength and stiffness under tensile, flexural, and impact loads. Finally, it can be affirmed that the treatments have increased the interfacial adhesion of the materials, contributing to the higher shear strength between the phases.