FTIR examination of preservative retention in beech wood (Fagus sylvatica L.)
A method of FTIR examination of preservative retention in beech wood structure was developed. Beech wood samples of different preservative content were prepared using low pressure preservation process in laboratory conditions. Then samples were homogenized in a laboratory mill and measurements were performed using FTIR spectrometer with attenuated total reflectance unit. Pure preservative was also measured and from its spectrum 1,555 cm−1 absorption band was chosen as the characteristic for preservative. 1,027 and 1,370 cm−1 were absorption bands characteristic for wood which were chosen as reference peaks. Values of two absorbance ratios, A1,555/A1,027 and A1,555/A1,370 were correlated with the preservative content in particular samples. Correlation coefficients were 0.8390 and 0.8313, respectively.
An evaluation of the influence of heat treatment on the preservative retention in ash wood (Fraxinus excelsior L.)
As high temperature followed by preservation may cause many different, sometimes contrary changes in wood properties, the aim of this paper was to determine the retention and possible distribution of copper containing preservative in ash wood with an X-ray spectrometer. Two solutions corresponding to the final retention 2 and 4 kg/m3 were applied as preservative for model laboratory scale low-pressure preservation of ash wood. Before preservation was made, samples were heat treated for 2 or 6 hours at 180°C, apart from the control samples. The mapping option of the X-ray spectrometer was applied and the surface on the half-cut cross-section was analysed. Copper was acknowledged as the retention indicator. On the basis of the results obtained, it can be assumed that the heat treatment improves the treatability of samples with the parameters used. Longer treatment durations increase the uptake of the preparation solutions.
Characterization of CDDC (Copper dimethyl dithiocarbamate) Treated Wood
This study investigates the chemical interaction between copper dimethyl dithiocarbamate (CDDC) and wood using various analytical tools such as environmental scanning electron microscopy (ESEM), X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform-infrared spectroscopy (FTIR). ESEM and XRD reveal CDDC crystalline deposits on wood cell wall-lumen interface with approximate particle size of 29nm. XRD patterns specific to SDDC (sodium dimethyl dithiocarbamate) were observed on treated wood but disappeared after water washing. XPS confirms the presence of copper (II) on CDDC treated wood similar to that of pure CDDC powder. FTIR suggests that copper from the copper monoethanolamine complex interacts with wood components through ligand exchange. The exchange is likely between carboxyl groups from carboxylic acids or lignin phenolic groups and the 2-ethanolamine ligand of the copper complex. In the second step treatment, CDDC is formed through interaction between copper retained by carboxyl groups and dimethyl dithiocarbamate from SDDC. The negligible solubility of CDDC in water and the 95 % removal by organic solvent extraction suggest that CDDC crystals are attached in wood through physical interaction.