Effect of heat treatment on the wettability of white ash and soft maple by water

Experimental techniques for characterising water in wood covering the range from dry to fully water-saturated

“…Despite the shortcomings of both methods as discussed by Wålinder and co-workers (Wålinder and Johansson 2001;Wålinder and Ström 2001), they both show that modification can alter the contact angle with water. For instance, both thermal modification (Bakar et al 2013;Hakkou et al 2006;Kocaefe et al 2008) and acetylation (Bryne and Wålinder 2010) appear to increase the contact angle with water, while furfurylation (Bryne and Wålinder 2010) slightly decreases it. The effect of these changes on the overhygroscopic sorption isotherms has not been investigated.…”

Surface Wettability of Wood Species from Tropical and Temperate Zones by Polar and Dispersive Liquids

“…Studies carried out so far (Zhang et al, 1997;Kúdela, 2014;Rolleri et al, 2016) show that the wettability of wood shows a signifi cant differentiation depending on the chemical composition, roughness, polarity of the wetting liquid, processing method and air parameters. Wood wettability is also signifi cantly affected by thermal treatment (Gérardin et al, 2007;Kocaefe et al, 2008) or fungicide protection, among others (Fuczek et al, 2010).…”

“…Authors studied the contact angle of wood with water for 50 s, with ethylene glycol for 10 s and with formamide for 1 s, while maintaining the appropriate intervals between the measurements. Santoni and Pizzo (2011) studied the contact angle of Mediterranean wood species with water at intervals of 0.3 s for 150 s. Kocaefe et al (2008) marked the contact angle of white ash (Fraxinus americana) and soft maple (Acer rubrum) before and after heat treatment within 30 s. Due to the dynamics of changes, the more rational solution is to defi ne the contact angle of wood with water for a specifi ed period of time. This makes it possible to determine more complete wettability characteristics of wood.…”

“…Wettability of wood is described by a number of parameters, of which the most studied and analysed are contact angle and surface free energy. Only a few authors examine wetting energy, spreading coeffi cient of reference liquid, work of adhesion for the phase boundary wood-liquid, surface tension of the liquid (Zhang et al, 1997;Kocaefe et al, 2008;Wolkenhauer et al, 2009;Gonzalez de Cademartori et al, 2015).…”

Mid-infrared spectroscopy and dynamic mechanical analysis of heat-treated obeche (Triplochiton scleroxylon)wood

“…In addition, an increase in crystallinity could be attributed to degradation/rearrangement of amorphous cellulose content (Hill 2006). Heat treatment of wood causes decomposition of hemicelluloses, ramification of lignin and crystallisation of cellulose (Kocaefe et al 2008); these changes result in reduction of swell of heat-treated wood (Calonego et al 2011). In an early study conducted by Tjeerdsma et al (1998), significant reduction in water adsorption of heat-treated wood was attributed to the increase in the relative proportion of the crystalline cellulose, in which the hydroxyl groups are not easily accessible to water molecules.…”