This research explores the potential introduction of marine waste-derived biological fillers within bio-epoxy matrices to mitigate the environmental impact of traditional materials, like fiberglass, in boat construction. However, this raises concerns about biofouling and degradation, issues that have not been extensively investigated in composites, especially over a time frame representative of issues that could arise during service. Although protective solutions like biocides and specific coatings exist, degradation remains challenging when attempting to use eco-friendly natural fillers. This study specifically integrates various biological fillers, namely ceramics (mussel, oyster, clam powder) or ligno-cellulosic (i.e., Posidonia oceanica fibers) into epoxy for use in some boat components (bench seats for the bridge deck), aiming to evaluate the biofouling process under extreme (or decommissioning) conditions. In itself, epoxy does represent an ideal enclosing matrix for biomass waste, which ideally needs to be introduced in significant amounts. The development of biofouling in the specific context of Kotor’s Bay, Montenegro, for a duration of six months, and relevant composite degradation were examined. In particular, three situations were reproduced by positioning the samples in a harbor environment: (i) on the bottom of the sea (2 m. depth), (ii) immersed just below the surface (0.5 m. depth), and (iii) on the splashing surface (pier). The concerns identified appear generally limited in the case of the envisaged application, despite some significant wear effect in the case of the samples containing Posidonia. However, this study also offers information and caveats in terms of more ambitious prospective applications (e.g., the boat hull structure).

Bio-epoxy composites were fabricated by casting a resin–hardener–filler mixture into 3D-printed molds, using different sea-originated secondary raw materials: mussel shell powder (MSP) (63–83 μm) and Posidonia oceanica short fibers (POF) (1–2 mm). Monofiller composites were prepared with 5 or 10 wt.% MSP, or 5 or 10 wt.% POF. Hybrid formulations were also produced, containing both MSP and POF in two combinations, where the total amount of filler again summed up at 10 wt.%. A subset of the samples was conditioned by immersion in a 35 ‰ NaCl solution reproducing seawater composition until saturation was reached. Characterization was carried out on unconditioned and conditioned samples by Shore D hardness and Charpy impact tests while performing three-point flexural loading only on unconditioned ones. Fracture morphology was also investigated. Adding MSP slightly enhanced resin hardness, whereas impact absorption exhibited, to a variable extent, a two-phase behavior, reproducing crack initiation and propagation. The MSP6-POF4 hybrid configuration provided the greatest improvement in absorbed energy (25–30% higher), which was retained after conditioning. The introduction of fillers, first separately, then in combination, resulted in a reduction in flexural strength to a similar extent for all unconditioned configurations. Finally, composite panels containing 10 wt.% MSP, 10 wt.% POF, and a 6MSP–4POF hybrid formulation, intended for prospective boat deck applications, were fabricated and compared with neat bio-epoxy, showing satisfactory consolidation. Density and post-molding dimensional shrinkage were measured on the panels.

Waste upcycling is often seen as a scattered concept, difficult to be put into practice in an educational yet scientific context. The idea is to provide an educational experience able to supply the students a wider perspective over how waste can be brought back into the productive system, until at all possible not. Outsourcing and characterization of waste, production of biofilms, home composting experiments. The experimentation gives a practical view of what is meant by circular economy moreover suggesting ideas about possible options for selecting waste and starting characterising it. In particular, it offers indications about the scientific method for testing materials including waste and being aware of their end-of-life, which all have influence on sustainability of the process. Ideally, depending on the time allotted for experiments, the work can be repeated iteratively to improve the results. Also, a database about possible local waste for DIY production of bioplastics can be generated over time, including considerations about ease of outsourcing, availability, seasonality, etc.