Innovation starts with waste and leads back to sustainability. This is the key message that emerged from the presentation by Dr Damiano Rossi of the University of Pisa, delivered at the III National Conference of the SCI Division of Chemistry for Technologies and the XIV AICIng Conference. His research, titled “Polyamide 6 recycled fishing nets modified with biochar fillers and reclaimed carbon fibres: an effort toward sustainability and circularity”, demonstrated how plastic waste and agricultural residues can be turned into advanced materials for industry.
The study is part of the activities of the CO-SMART project, promoted by the National Centre for Sustainable Mobility (MOST) and supported by the National Recovery and Resilience Plan (PNRR), under Spoke 11, which focuses on the development of innovative materials for mobility and the environment.
Recycled and reinforced fishing nets: a new life for marine plastic
Every year, over 640,000 tonnes of fishing nets end up in the sea, accounting for around 20% of marine plastic. Rossi’s research team tackled this issue with a circular approach: converting recycled polyamide 6 (PA6) from discarded nets into advanced polymer composites, strengthened with biochar (plant-based carbon from agricultural waste) and reclaimed carbon fibres.
Dual reinforcement: biochar and regenerated carbon fibres
The study followed two main research pathways:
- In the first, recycled polyamide was reinforced with lignocellulosic biochar (5–15% by weight), improving the elastic modulus (from 2.6 to 4.5 GPa) and moisture resistance (with a 50% reduction in water absorption). Particularly noteworthy was the use of rice husk biochar, which exhibited flame-retardant properties thanks to its silica content—without compromising mechanical performance.
- In the second pathway, carbon fibres were regenerated through an innovative two-step thermo-oxidative process, preserving their original size and strength while increasing surface activation, thus improving adhesion to the polymer matrix.
The results were striking: composites containing 15% regenerated carbon fibres achieved a tensile modulus of 13.1 GPa (compared to 3.2 GPa for unreinforced rPA6) and an impact toughness of 28.4 kJ/m²—almost three times that of the unreinforced material.
The environment benefits: -5.7 tonnes of CO₂
What made the work even more significant was the Life Cycle Assessment (LCA) approach, which quantified the environmental benefits: a reduction of over 5,700 kg of CO₂ equivalents compared to the use of virgin materials, proving that recycled composites are winners even from an emissions standpoint.
CO-SMART: circularity that delivers
Damiano Rossi’s presentation provided concrete proof of how circular economy principles can lead to high-performance, low-impact materials, with potential applications in the automotive sector, shipbuilding, and technical components.
In line with the CO-SMART project, this research advances a vision that blends science, sustainability and technology, transforming the problem of marine plastic into an opportunity to build a cleaner, safer, and smarter future.
