Thermal behavior of heat-treated wood using two-dimensional correlation of near-infrared spectroscopy and differential scanning calorimetry

Heat treatment of wood can decrease its heat capacity and thermal transitions, which are thermal behavior properties of wood. A calorimetric study that highlights the thermal behavior of the molecular mobility of materials is necessary to investigate the thermal degradation of wood. Furthermore, combining it with a nondestructive measurement technique would widen its scope of applicability, especially for wood in service or historical wood that cannot be altered or damaged by invasive methods. Neolamarckia cadamba (Roxb.) Bosser, also known as burflower-tree, a tropical fast-growing hardwood species that has become popular for light-construction works in the past decade, is treated at 90, 120, and 150 celcius for a duration of 8 h to 3.5 months, scheduled logarithmically. Near-infrared spectroscopy and differential scanning calorimetry (DSC) were used to measure the chemical changes and thermal behavior of the wood before and after heat treatment. Two-dimensional correlation spectroscopy (2DCOS) analysis was then applied to assess the NIR second-derivative spectra and DSC thermograms. The results showed that 2DCOS analysis could assess NIR second-derivative spectra and DSC thermograms under careful observation, as DSC thermograms comprise both qualitative and quantitative information. It provides a new point of view in the non-destructive analysis of wood thermal degradation.