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This work examined the chemical interrelations between melamine–formaldehyde (MF) and waterlogged archaeological wood to demonstrate the effect of the MFtreatment on cultural heritage objects. Samples from a Roman waterlogged trunk of Greek fir, were analyzed with Fourier Transform Infrared Spectroscopy (FTIR), solid-state 13C Nuclear Magnetic Resonance (NMR), analytical pyrolysis with in-situ silylation Py(HMDS) coupled with Gas Chromatography Mass Spectrometry (GC/MS) and Evolved Gas Analysis-Mass Spectrometry, (EGA-MS) before and after the MFtreatment. FTIR results showed the formation of amide functionalities due to melamine reactions and strong evidence of lignin modification, while the deteriorated cellulose fraction appeared to have undergone further depletion as a result of the MF treatment. The 13C NMR spectra of the MF-treated wood clearly demonstrated the presence of the resin within the wood and indicated that MF carbons were strongly interacting with lignin moieties. Spectra also revealed that the retention of the MF resin in the wood was positively correlated to the degree of wood degradation. Py(HMDS)-GC/MS of MF-treated wood provided few peaks attributed to holocellulose or lignin pyrolytic products, and it was not possible to detect any signs of non-MF-modified wood components, as the lignocellulosic wood matrix appeared to have been transformed into a new biopolymer. EGA-MS profiles of the MF-treated archaeological wood showed early evolution of volatiles due to free MF retained in the wood, while its thermal stability appeared increased in comparison to untreated material. Nonetheless, mass peaks indicated that the chemistry of MF-treated wood was completely different from both fresh and untreated deteriorated wood. Overall, results showed that the MF treatment irreversibly modified the residual chemistry of the archaeological material and failed to preserve its original physical and historical integrity. This permanent modification of unknown longevity is considered not in line with conservation ethics and, therefore, inappropriate for the long-term preservation of cultural heritage objects. [ABSTRACT FROM AUTHOR]

This review describes the capability of analytical pyrolysis-based techniques to provide data on lignin composition and on the chemical alteration undergone by lignin in archaeological wooden objects. Applications of Direct Exposure Mass Spectrometry (DE-MS), Evolved Gas Analysis Mass Spectrometry (EGA-MS), and single and double-shot Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS) in archaeological lignin characterisation are described. With comparison to cellulose and hemicelluloses, lignin is generally less prone to most degradation processes affecting archaeological artefacts in burial environments, especially waterlogged ones, which are the most favourable for wood preservation. Nevertheless, lignin also undergoes significant chemical changes. As wood from waterlogged environments is mainly composed of lignin, knowledge of its chemical structure and degradation pathways is fundamental for choosing preventive conservation conditions and for optimising consolidation methods and materials, which directly interact with the residual lignin. Analytical pyrolysis coupled with mass spectrometry, used in several complementary operational modes, can gather information regarding the chemical modifications and the state of preservation of lignin, especially concerning oxidation and depolymerisation phenomena. Several applications to the analysis of wood from archaeological artefacts affected by different conservation problems are presented to showcase the potential of analytical pyrolysis in various scenarios that can be encountered when investigating archaeological waterlogged wood. [ABSTRACT FROM AUTHOR]

The COST EU-PoTaRCh Action establishes a network focused on the past, present, and future significance, production, and use of major forest by-products in Europe and beyond. The Action centers around forest by-products-primarily potash, tar, resin, and charcoal (PoTaRCh), along with plant extracts-which have been produced and utilized for over 100,000 years due to their unique chemical, biological, and therapeutic properties. The primary goal of the Action is to demonstrate the importance of these products for the socio-economic development of European countries and beyond, as well as their impact on biodiversity and the natural environment. The Action's objectives are organized into five Working Groups (WGs), each aligned with specific areas of interest: heritage, chemical characterization, archaeology, environmental history, and future perspectives of PoTaRCh materials. A key aspect of the Action is its support for stakeholders outside the scientific community who possess knowledge of PoTaRCh products through their use in industries such as production, education, and the promotion of forests' natural and cultural heritage. In doing so, the Action brings together stakeholders with diverse activity profiles, including museums, state forests, the forestry industry, associations dedicated to preserving traditions, and the tourism sector. The EU-PoTaRCh Action adheres to the three key principles of COST's inclusiveness policy: participation of inclusiveness target countries, gender balance, and the involvement of young researchers, including in leadership positions., Competing Interests: No competing interests were disclosed., (Copyright: © 2024 Zborowska M et al.)