Enhancing mechanical properties of PLA and PP composites through ionic zeolite with copper nanoparticle reinforcement: microstructural and micromechanical characterization

Three-dimensional printing has experienced steady growth across various industries, but its application in the production of biomedical devices and components is hindered by the lack of materials with suitable mechanical properties and controlled bioactivity. Most polymers have limitations in terms of their strength and bioactivity, necessitating the incorporation of special features to overcome these shortcomings. Among these polymers are polylactic acid (PLA) and polypropylene (PP), which are highly reusable materials. Zeolite, a widely available natural material, has the potential to address these bioactivity and strength limitations. Therefore, this study focuses on the development of composite materials, specifically PLA + zeolite and PP + zeolite, doped with Cu nanoparticles. The goal is to obtain composite materials capable of effective application in the biomedical field through 3D manufacturing, providing an efficient, cost-effective, and non-toxic alternative. The methodology employed involved extrusion manufacturing, followed by the validation of zeolite dispersion in PP and PLA through optical microscopy and the analysis of zeolite morphology using scanning electron microscopy. The mechanical response of the materials was determined through nanoindentation tests and tensile experiments. The results obtained revealed an appropriate dispersion of zeolite in both polymer matrices. Nanoindentation tests highlighted significant anisotropy and an auxetic response in zeolite. However, virtual tests demonstrated a high precision between submicrometric and macrometric scales in the composite materials. Tensile tests indicated a substantial increase in the stiffness of the composite upon zeolite incorporation, with a 21.48% increase in the case of the PLA matrix compared to PLA without zeolite, and a 19.12% increase in the case of PP compared to PP without zeolite. These results hold promise for the fabrication of filaments intended for additive manufacturing processes in the biomedical field, offering an accessible and effective solution. Graphical abstract