Understanding decay resistance, dimensional stability and strength changes in heat-treated and acetylated wood

Mode of action of brown rot decay resistance in modified wood: a review

“…As pointed out above, brown rot fungi degrade hemicelluloses before cellulose (Militz 2002;Weiland and Guyonnet 2003;Rowell et al 2009) and this order of degradation is considered by many investigators to be a key step (Boonstra et al 2007;Rowell et al 2009). Rowell et al (2009) proposed that arabinose, which is the only L-pentose sugar found in wood, is a key compound that triggers the chain reactions of degradation and that its absence would prevent the initiation of degradation.…”

“…The optimization of processes and product properties could be further improved by a better understanding of the underlying mechanisms of inhibition or delay of biological degradation after nontoxic modifications. Decay resistance has been reviewed independently for acetylated wood (Papadopoulos 2010) and thermally modified wood (Esteves and Pereira 2009) as well as in a combined review (Rowell et al 2009). Previous research concerning the degradation of cellulose by brown rot fungi was summarized by Baldrian and Valaskova (2008).…”

Chemical Modification of Wood by Acetylation or Furfurylation: A Review of the Present Scaled-up Technologies

“…Today, the acetylation process, as applied in liquid phase, yields chemically modified timber that has considerably improved physical, mechanical, and biological material properties (Hill 2006;Jones and Hill 2007;Rowell et al 2009;Larsson-Brelid 2013;Alexander et al 2014;Gérardin 2016), which are presented below.…”

“…Currently, much is known about the modes of action of modified wood, which includes the following: i) the equilibrium moisture content is lowered in modified wood, and hence it is harder for fungi to obtain the moisture required for decay; ii) there is a physical blocking of the entrance of decay fungi to micropores of the cell walls; and/or, iii) inhibition of the action of specific enzymes (Hill 2006;Rowell et al 2009;Rowell 2012). These three are only parts of the whole mechanism.…”

“…It can be degraded by a wide variety of microorganisms, it burns, and it is decomposed by ultraviolet energy (Stamm 1964;Rowell 1983). With an increased awareness of the fragility of the environment and the need for durability in wood products, new technologies have been developed to increase the service life of wood without the use of toxic chemicals (Rowell 1983(Rowell , 1984Militz 1991;Westin 1996;Hill 2006;Rowell et al 2009;Rowell 2012;Gérardin 2016). Issues of sustainability and carbon sequestration converge in this search for new 'green' technologies to improve durability, stability, and performance of wood, especially in exterior applications (Rowell 2016).…”