Moisture content deteriorated wood

Free radicals are generated at the wood surface during irradiation. The rate of free radical formation is enhanced when moisture content increases from 0 to 6.3%. Electron spin resonance and UV studies on the behavior of free radicals generated and their interactions with oxygen molecules to form hydroperoxides revealed that free radicals and singlet oxygen play important roles in discoloration and deterioration reactions of wood surfaces. 

Wood for charcoal production must first be cut, split and dried because wet wood has a low heat value. In the moist tropics it is difficult to hold timber in stack for more than a couple of months without noticeable deterioration, but even in that time the moisture content can drop from 60% towards 30%. Stock holding also ensures continuity of supply. 

Moisture Content. In a specific circumstance (a treatment problem of a group of oak timbers), the moisture content and the amount of internal sound wood core were used instead of chemical analyses to assess degradation (6). The wood condition has been classified as follows Class I, the most deteriorated wood, contains over 400% water ([weight of water] / [oven-dry weight of wood] X 100) and virtually no core Class II is 185-400% water, with a core present and Class III is less than 185% water, with only the surface degraded. The analyses included moisture contents and the pin test to determine the extent of sound wood. 

The type of pretreatment depends on the moisture content of the wood and its degree of deterioration. For slightly deteriorated woods, no pre-... 

Strength of the bulk wood will depend, first, on the wood s density, grain pattern, grain direction, and moisture content. Second, it will depend on any damage or deterioration the wood may have suffered. Deterioration will normally be quite significant with archaeological wood, and considerably more attention will be given to it later. 

Well-designed and well-made joints should retain their mechanical properties indefinitely if the wood moisture content stays within reasonable limits (i.e., < 15%) and if the temperature remains within the range of human comfort. However, when bonded joints are exposed either intermittently or continuously to abnormally high or low temperatures for long periods they will eventually deteriorate [23]. 

Moisture Moisture variations are usually caused by rain, snow, hail, frost, and dew. Changes in humidity lead to changes in equiUbrium water content. When moisture increases, water vapor is absorbed by WPCs, particularly wood. When moisture decreases, wood shrinks. The changes in moisture accelerate the deterioration of wood flour/plastic interface bonding. 

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