Multiscale modification on water resistance and dimensional stability of Populus cathayana by alkali lignin combined with heat treatment

IRG/WP 18-40826

H Zhou, J Li, E Ma

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.


Keywords: wood, modification, alkali lignin, water resistance, dimensional stability

Conference: 18-04-29/05-03 Johannesburg, South Africa


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