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Changes in the degree of decay of lignocellulosic substrate used in a screening test of fungicidal wood preservatives
1977 - IRG/WP 287
This report contains results of investigations aimed at: a) determination of the effect of the kind of substrate and species of test fungus on quantitative changes in used samples prepared from spruce cardboard, and b) comparison of the threshold fungicidal values of come fungicides determined with accelerated method, with values obtained by block method. During performed investigations, the method described in Document No.: IRG/WP/262 was used. Assesment of decomposition degree was based on the loss of weight and amount of NaOH consumption by the substrate.
Effects of alkali treatment on some mechanical and chemical properties of creosote treated oaks
1991 - IRG/WP 2366
To date, there is a lack of information on the effects of chemical treatment on the performance of creosote preservative treated oak sleepers. This factorial experiment was designed to analyze three main effects: species (Quercus alba and Quercus rubra) creosote treatment (treated and untreated), and alkali (NaOH) soaking (0, 1, and 10 percent). The modulus of elasticity (MOE) and fiber stress at proportional limit in compression perpendicular to grain, hardness modulus, surface hardness, alcohol-benzene extractives, hot-water extractives, 1% NaOH extractives, lignin, pentosans, holocellulose, and alpha-cellulose content were determined on specimens. The test results indicated that species, creosote treatment, and alkali soaking significantly affect both the mechanical and chemical properties of the oak sleepers.
P Chow, A J Reinschmidt, E J Barenberg, L C Chang
Multiscale modification on water resistance and dimensional stability of Populus cathayana by alkali lignin combined with heat treatment
2018 - IRG/WP 18-40826
The aim of this study was to enhance the water resistance and dimensional stability of fast growing wood by alkali lignin combined with heat treatment. Poplar (Populus cathayana) samples were first impregnated with alkali lignin solution and then subjected to heat treatment at 140, 160, and 180°C respectively for 2h. Properties of leachability, moisture adsorption and water absorption, contact angle, tangential and volumetric swelling for the control and modified samples were investigated. Moreover, the morphological and chemical alterations were analyzed by scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM) and Fourier transform infrared (FTIR) spectroscopy. The results indicated that all of the alkali lignin treated wood showed a great leaching resistance. What’s more, alkali lignin treatment was capable of improving surface hydrophobicity and decreasing moisture and water uptake and thus the dimensional instability of modified wood. These changes were more obvious as the heat-treating temperature increased. The results of SEM, CLSM and FTIR suggested that the alkali lignin existed in cell lumen as well as cell wall of wood fibers and vessels, and small alkali lignin molecules may react with wood matrix. Results from this study could not only enrich the approach as well as reduce the cost of wood modification, but also achieve the aim of higher value application for industrial lignin.
H Zhou, J Li, E Ma