Amongst polyphenols, tannins belong to the most effective chemical protection systems against biological attack on trees. Tannins are water-soluble and are thus leached out easily when used for wood protection. In situ polymerized tannin-hexamine wood preservatives have better leaching resistance (LR), but they do not resist weathering. In this study, tannin copolymer formulations were prepared with hexamine, formaldehyde, furfural, glyoxal, furfuryl alcohol and maleic anhydride, impregnated in wood, and cured at higher temperatures. The wood samples treated with these formulations were tested for their anti-swelling efficiency (ASE), leaching behavior, mechanical properties, and their resistance against fire, weathering and biological attack. Several tannin-treated specimens showed improved hardness and enhanced leaching and fire resistance. Some formulations also responded well to artificial weathering cycles, but natural weathering cycles deteriorated their performance. Samples treated with maleic anhydride showed improved leachability and high biological resistances, even without the addition of inorganic biocides. These organic and bio-friendly products can be considered as promising alternatives to heavy metal-based wood preservatives.

Plant species have developed effective defense strategies for colonizing diverse habitats and protecting themselves from numerous attacks from a wide range of organisms, including insects, vertebrates, fungi, and bacteria. The bark of trees in particular constitutes a number of components that protect against unwanted intruders. This review focuses on the antioxidative, dermal immunomodulatory, and antimicrobial properties of bark extracts from European common temperate trees in light of various skin pathogens, wound healing, and the maintenance of skin health. The sustainability aspect, achieved by utilizing the bark, which is considered a byproduct in the forest industry, is addressed, as are various extraction methods applied to retrieve extracts from bark.

Furfuryl alcohol (FA) and lactic acid (LA) are two of the most interesting biomolecules, easily obtainable from sugars and hence extremely attractive for green chemistry solutions. These substances undergo homopolymerization and they have been rarely considered for copolymerization. Typically, FA homopolymerizes exothermically in an acid environment producing inhomogeneous porous materials, but recent studies have shown that this reaction can be controlled and therefore we have implemented this process to trigger the copolymerization with LA. The mechanical tests have shown that the blend containing small amount of FA were rigid and the fracture showed patterns more similar to the one of neat polyfurfuryl alcohol (PFA). This LA-rich blend exhibited higher chloroform and water resistances, while thermal analyses (TG and DSC) also indicated a higher furanic character than expected. These observations suggested an intimate interconnection between precursors which was highlighted by the presence of a small band in the ester region of the solid state 13C–NMR, even if the FT-IR did not evidence any new signal. These studies show that these bioplastics are basically constituted of PLA and PFA homopolymers with some small portion of covalent bonds between the two moieties.