Study of Chemical Modification by Impregnation of Fresh Poplar Log and by Hot-Press Drying Process

Abstract

In this work, fresh poplar logs were chemically impregnated with a pulsedipping machine. The impregnated timbers were compressed and dried by use of a multilayer hot-press drying kiln. With a compression rate of 28.67%, such an approach not only enhanced the density and mechanical properties of the treated wood, but also influenced the set recovery from the compressive deformation. Extra urea was added into the modifier to optimize the effect of the set recovery; however the result was a slight decrease in the mechanical properties. The positions of the X-ray diffraction (XRD) peaks did not change, which indicated that the structure of the cellulose was not noticeably affected by this treatment. The Fourier transform infrared spectroscopy (FT-IR) analysis showed that the intensity amide (N-C=O) absorption peak increased significantly due to the chemical impregnation. Scanning electron microscopy (SEM) showed that the high strain in the hot-press process drastically reduced the volume of void spaces in the specimens and deformed the cell lumens.

The Effect of Chemical Changes during Heat Treatment on the Color and Mechanical Properties of Fir Wood

“…These disadvantages were overcome by the use of a durable hardwood species, particularly tropical hardwoods, or by means of wood preservation. The most common method for increasing the decay resistance of wood is the application of various chemicals (Hill 2006;Papadopoulos 2010;Wu et al 2010;Chen et al 2013;Xie et al 2013;Han et al 2015;Osvaldová et al 2016), but chemical treatments may have a negative environmental impact during their production, service life, and in their disposal or recycling situations (Hill 2006;Kocaefe et al 2008). Thermal treatment is a different method for the improvement of wood properties (Seborg et al 1953;Alen et al 2002;Militz 2002;Gurdil et al 2009;Allegretti et al 2012;Bazyar 2012;Cademartori et al 2015;Missio et al 2015;Candelier et al 2016;Missio et al 2016).…”

Determination of the Combined Effect of Chemical Modification and Compression of Agatis Wood on the Dimensional Stability, Termite Resistance, and Morphological Structure

“…If there are changes in the shape regularity structure, flexibility will be lower because wood density increases. This phenomenon shows that cells in wood filled with chemical agents changed the preferred orientation of wood by replacement of hydroxyl groups with monomers that polymerize with wood (Chen et al 2013). Wood modification results in an increase in the crystallinity of modified agatis wood, as shown by X-ray diffraction (Fig.…”

“…Many attempts have been made to stabilize the compressed deformation of wood permanently by resin treatment (Inoue et al 1991;Dungani et al 2014) and chemical modification (Inoue et al 1994;Bhat et al 2011;Chen et al 2013). Several studies have been conducted on densifying wood by impregnation using the monomers styrene (ST), methyl methacrylate (MMA), and glycidyl methacrylate (GMA).…”

Moisture state variety in poplar lumber with moisture content above fibre saturation point during hot-press drying

“…Hot-press drying shows advantage in improving drying rate and surface strengthening of wood [1]. The hot-press drying characteristics of wood have been studied [2][3][4][5]. And most of these investigations focused on the effects of drying on drying time [6], drying quality [7], physical-mechanical properties [8] and microstructure [9] of hot-press drying wood.…”