Heat-treated lignin

Figure 12. The rate of free radical formation (—A—) and weight loss (—A—) on heating of lignin and treated lignin...

Fig. 4.8.14. Heat capacity (Cp) curves of quenched (cooled rapidly) and annealed (heat-treated) dioxane lignin A quenched from 423 K to 310 K, B annealed at 395 K for — 60 min, — lOOmin, - 940min, 1300min (Hatakeyama et al 1982)...

Figure 7. DSC curves of H202 treated lignin-cellulose mixtures. Conditions closed aluminum pan with a pinhole 975 psi N2 pressure 20 °C min heating rate. (Reproduced with permission from Ref 142. Copy-right 1982y Gordon and Breach Science Publishers.)...

Tall oil rosin is a by-product of paper manufacturing. Raw wood chips are digested under heat and pressure with a mixture of sodium hydroxide and sodium sulfide. Soluble sodium salts of lignin, rosin, and fatty acids are formed, which are removed from the wood pulp as a dark solution. The soaps of the rosin and fatty acids float to the top of the mixture, where they are skimmed off and treated with sulfuric acid to free the rosin and fatty acids. This mixture, known as cmde tall oil (CTO), is refined further to remove color and odor bodies fractional distillation separates the tall oil rosin acids from the fatty acids (see Tall oil). 

The lignin hypothesis implies that the active copper fungitoxicant is fixed by ion exchange to the lignin. The importance of the fixation mechanisms has not been accounted for, but soft-rot attack in hardwood treated with CCA was accelerated when the wood was subjected to rapid fixation of the preservative at elevated temperatures after treatment (3J). Undoubtedly, the change in fixation mechanisms caused by the heat treatment has a marked effect on the control of soft-rot decay. This observation is also compatible with the fixation and lignin hypothesis theories. 

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