The effect of aging on lignins of wood

Application of FTIR spectroscopy to the characterization of archeological wood

“…This probably explains why lignin was more abundant in the shipwreck timber, even though a combined source and environment effect cannot be ruled out. Previous FTIR studies showed that lignin is partially oxidized when wood is under dry air conditions during a long period, causing an increase in the relative proportion of carbonyl groups (Borgin et al 1975, Wilson et al 1993). However, wood under anoxic conditions may undergo hydrolysis followed by leaching of the hydrophilic carbohydrates, contributing to the dominance of the lignin proportion (Borgin et al 1975, Wilson et al 1993, Colombini et al 2007).…”

“…Previous FTIR studies showed that lignin is partially oxidized when wood is under dry air conditions during a long period, causing an increase in the relative proportion of carbonyl groups (Borgin et al 1975, Wilson et al 1993). However, wood under anoxic conditions may undergo hydrolysis followed by leaching of the hydrophilic carbohydrates, contributing to the dominance of the lignin proportion (Borgin et al 1975, Wilson et al 1993, Colombini et al 2007). Gelbrich et al (2008) also found a high degree of degradation of archaeological wood, average lignin content increasing from 25% in fresh wood to up to 45% in archaeological wood.…”

Natural and artificial ageing of spruce wood as observed by FTIR-ATR and UVRR spectroscopy

“…The crystalline structure of cellulose in 300-400-year-old wood does not differ from fresh, unaged, wood. However, the degree of condensation of lignin and the number of polyconjugated systems increases as a result of oxidation and the amount of acid soluble lignin decreases (Borgin et al 1975). In thermal treatment, a decrease in the amorphous polysaccharide content is observed, as well as condensation and (Tjeerdsma et al 1998;Nuopponen et al 2004).…”

“…Fourier transform infrared spectroscopy (FTIR) spectroscopy is an analytical technique well suited for studying the changes that take place in wood during ageing or weathering (Borgin et al 1975;Fengel 1991;Horn et al 1994;Müller et al 2003;Pandey and Pitman 2003;Popescu et al 2005;Ucar et al 2005;Dobrica et al 2008). It is recognised thaţ a decrease in polyose content occurs during natural ageing as a result of a slow hydrolysis initiated by acetic acid which originates from cleaved O-acetyl groups of hemicelluloses.…”

15. Aging and Fossilization

“…Borgin et al (1975b) found oxidative changes in the lignin molecules of samples with ages of 900-4 400 years. Borgin et al (1975b) found oxidative changes in the lignin molecules of samples with ages of 900-4 400 years.…”