Timbers softened

Nail sickness Nail sickness is chemical decay associated with corroded metals in marine situations. Chemical degradation of wood by the products of metal corrosion is brought about by bad workmanship or maintenance, or unsuitable (permeable) timber species, all of which permit electrolyte and oxygen access which promotes corrosion. Chemical decay of wood by alkali occurs in cathodic areas (metal exposed oxygen present). Softening and embrittlement of wood occurs in anodic areas (metal embedded oxygen absent) caused by mineral acid from hydrolysis of soluble iron corrosion products. 

Some materials may bum quite slowly but may propagate a flame rapidly over their surfaces. Thin wood paneling will burn readily, yet a heavy timber post will sustain a fire on its surface until it is charred, then smolder at a remarkably slow rate of burning. Bituminous materials may spread a fire by softening and running down a wall. Steel of course does not burn, but is catastrophically weakened by the elevated temperatures of a fire. PVC does not bum, but it softens at relatively low temperatures. Other plastics may not burn readily but still emit copious amounts of smoke. And some flammable plastics, such as... 

Abrasive action by water and sand in aquatic environments may remove the outer softened layers of soft-rotted timber, and thus expose the underlying layers for further attack (76). This exposure will result in a more extensive attack at the water level, giving a characteristic appearance of the smooth rounded shapes common to driftwood. Wood-degrading bacteria may often also contribute to the surface softening in aquatic environments. 

Fatty acids are raw materials for fatty amines, ethoxylated fatty amines, quaternary ammonium compounds (Quats), fatty acid-polyamine condensates, fabric softeners based on esterquats, fatty add amides, alkyl keten dimers for paper sizing and amphoteric surfactants. Binding of oleic add anhydride to cellulose fibre by chemical grafting is a recently introduced sustainable process to protect construction timber for outdoor use, such as pinewood shutters, from moisture and outside attack. Impregnation of the wood involves two stages firstly in an autoclave, where vacuum and pressure ensure its penetration, and then in a tank where the wood is soaked in a bath of anhydride, to encourage grafting of the anhydride on the wood. ... 

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