Decay anhydride modified wood

HUl, C.A.S., Forster, S., Farahani, M.R.M., Hale, M.D.C. and Williams, G. (2005). An investigation of cell wall micropore blocking as a possible mechanism for the decay resistance of anhydride modified wood. International Bio deterioration and Biodegradation, 55(1), 69-76. 

As noted previously in Chapter 3, the improved dimensional stability of wood as a result of anhydride modification has been found to be a function of WPG only, irrespective of the anhydride used for modification (Stamm and Tarkow, 1947 Hill and Jones, 1996b Li etal., 2000b). This shows that improved dimensional stability arises due to a bulking phenomenon, caused by the volume occupied by the bonded acyl adducts in the cell wall. The dimensional stabilization of wood modified with crotonic anhydride has also been reported ( etin and Ozmen, 2001). Reductions in the EMC have also been attributed to a bulking phenomenon (Papadopoulos and Hill, 2003), and in at least one example of decay protection (Papadopoulos and Hill, 2002). Further research is needed to determine if this is the case for resistance to other decay organisms. Only with the phenomenon of surface wettability does the relationship between a physical property of chemically modified wood and WPG seem to be broken (Hill and Jones, 1996c) (Table 4.1). 

The resistance of propylene and butylene epoxide modified wood to subterranean termites was studied (Rowell etal., 1979). A threshold of 34 % WPG was found to give good protection. Giant ipil ipil (Leucaena leucocephala) was modified with acetic anhydride, maleic anhydride - glycerol or propylene oxide (Mallari etal., 1988, 1990). All modified samples showed good decay resistance to C. versicolor and Tyromyces palustris. 

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