Mechanical properties and antimicrobial activity of pumice stone/sludge filled thermosetting composites

The exploitation of natural quarries generates a high amount of waste as a result of the extraction, screening and segmentation processes. These usually inert wastes are not typically reused and end up in landfills. There is an urgent need for sustainable solutions aiming at the valorisation of these mineral wastes through the development of innovative products with greater added value and active functionalities. In this work, the applicability of different mineral wastes was tested on the development of advanced active ecocomposites. Several formulations/conditions, using green epoxy and polyester matrixes, were assessed in order to determine the reasonable production parameters. Additionally, two different antibacterial agents were added and the efficacy was tested. The overall mechanical performance of the ecocomposite was evaluated during every stage of development. The combination of dried sludge and green epoxy resin (SE_70), containing 70% of mineral waste, revealed to be most promising composition with interesting mechanical properties (tensile strength 91.63 ± 3.31 (MPa); strain (%) 0.69 ± 0.05; and Young's modulus (GPa) 13.65 ± 0.64). The functionalization of these samples was successful and the antibacterial activity was confirmed. However, the active agent affected the short-term mechanical properties. Nevertheless, the QUV® accelerated weathering test confirmed that the main long-term properties were unaffected. Thus, it is concluded that mineral waste from quarry activities can be use in the development of new sustainable added value advanced products.