Verso un'industria del legno più verde: Esplorazione delle resine naturali a base di tannino per prodotti in legno ingegnerizzati sostenibili.

Nowadays, the transition toward renewable resources is crucial for addressing environmental challenges. Wood material, known for its versatility and sustainability, offers a durable and recyclable alternative to finite fossil resources. The wood industry is a significant adhesive consumer, and can drive eco–friendly policies by adopting environmentally conscious solutions. In this context the objective of the current study is to investigate a range of natural resins tailored for the production of engineered wood products, offering sustainable alternatives to conventional synthetic resins. The research has begun with a preliminary study of different tannin–based resins, proposing different hardeners and studying the physical and chemical characteristics of the resins, and thus the most promising formulations suitable for our study's objectives have been identified. Hence, the most interesting formulations have been applied in the production of engineered wood products. Specifically, a tannin–hexamine resin has been used to impregnate various wood species, showing that low percentages of the hardener (<5%) are sufficient to increase the mechanical properties of the wood. Instead, furans–tannin resins have been utilized for the production of plywood and particleboards. Although acceptable results have been shown for applications in dry environments, limitations for wet purposes have been reported. In this direction, a protein counterpart, silk fibroin, within a promising tannin–based formulation has been proposed to improve moisture tolerance. The results have shown how low amounts of silk fibroin lead to a substantial increase in mechanical properties, also in a humid environment. Finally, in a general perspective of sustainable development and in cooperation with the producers of the silk cocoons, an environmental impact analysis carried out with the Life Cycle Assessment methodology, has been developed. This environmental impact study aimed to revitalize the Italian industry of silk production, while also providing a comparative analysis with similar studies performed in different international contexts. Those researches consistently highlight silk as having the highest environmental impact among fibre–based materials. However, sustainable and non–intensive agricultural practices involved within the Italian supply chain have demonstrated a reduced environmental impact compared to intensive methods. However, specific hotspots in the supply chain have been identified and reported in order to enhance the overall sustainability in the process. In conclusion, this research provides a comprehensive exploration of tannin-based resins, utilizing a commercial extract as a polyphenolic matrix.