Effects of heat treatment on brittleness of Styrax tonkinensis wood

Abstract

A new approach is proposed for the evaluation of the brittleness of heat-treated Styrax tonkinensis wood. Heat treatment made wood more brittle when wood was heated at a higher temperature or for a longer time. The brittleness increased to four times that of the control when wood was heated at 200°C for 12 h. For treatment at 160°C, the increase in brittleness without any change in weight is thought to be possibly caused by the relocation of lignin molecules. At higher temperatures, loss of amorphous polysaccharides due to degradation is thought to become the main factor affecting brittleness. The crystallites that were newly formed after 2 h of treatment showed brittleness that was different from that of the inherent crystallites remaining after 12 h of heat treatment. This inherent crystalline cellulose possibly plays a role in brittleness. There is also the possibility of using color to predict the brittleness of heat-treated wood.

Influence of thermal modification on nail withdrawal strength of spruce wood

“…The average density of control spruce was 433 kg/m 3 . This value corresponds to the 420 kg/m 3 indicated by Mayes and Oksanen (2003) or 443 kg/m 3 found by Kariz et al (2013). Arnold (2010) found a lower value of density, 402 kg/m 3 .…”

“…The EMC values of native wood correspond to moisture content under conditions of φ = 65 ± 3% and t = 20 ± 2 °C. While the control spruce wood reached a moisture content of approximately 12%, thermal modification reduced EMC to half that of the unmodified wood (4 to 6%, depending on the temperature, as stated by Mayes and Oksanen 2003). Kariz et al (2013) found 5% moisture content of spruce wood after thermal treatment at 230 °C, and Arnold (2010) found a 60% decrease in EMC after thermal modification at 180 to 220 °C.…”

“…The product also has excellent dimensional stability. Reducing the moisture content of the material by more than 50% is attained by significantly lowering the moisture absorption and shrinkage of the material (Mayes and Oksanen 2003). In addition, there are also numerous wood-deteriorating effects, such as bulging, twisting, warping, and other deformations.…”

The effect of thermal treatment on physical and mechanical properties of Luehea divaricata hardwood

“…After the mechanical tests, the load-deflection curves were analysed in order to estimate the brittleness of untreated and thermally treated wood according to the methodology described by Phuong et al (2007).…”

Impact of Thermal Modification of Spruce Wood on Screw Direct Withdrawal Load Resistance

“…The first sign of the modification is a darkening in coloration. In addition to a change in color, there are also changes in the primary physical and mechanical properties of the wood (Požgaj et al 1993;Vernois 2001;Yildiz et al 2006;Phuong et al 2007;Esteves and Pereira 2009;Gaff and Matlák 2014;Fekiač et al 2015). The most significant effects registered have been in wood density, dimensional stability, and moisture absorption.…”