Whole Wood as a Potential Source for Shaped Articles

A review of the effect of heat and pressure on wood, particularly the techniques used to “reform” wood particles into shaped articles without the use of added chemical binders. Two classes of reaction are distinguished: “open” systems, in which the volatile decomposition products of wood are allowed to escape, and “closed” systems in which the cleavage products can be recombined quantitatively. In open systems oxidative degradation predominates; in closed systems hydrolytic degradation predominates because of the formation and retention of volatile acids. Reforming conditions require pressures in excess of 1,000 psi and temperatures from 200 to 400?F. Water was found to be essential to the reforming process, so that a closed system is required. An industrial application of the reforming technique is the Runkel process used in the manufacture of toilet seats in West Germany, which uses pressures of from 1,200 to 2,500 psi, and forms these molded products without added resin binder.

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