Chemistry of wood strength

This chapter presents a theoretical model to explain the relationship between the mechanical properties and the chemical components of wood. This model is then used to describe the effects of altered composition on those mechanical properties. Many of the theories presented are unproven. They should be considered as a starting point for dialogue between chemists and engineers that will eventually lead to a better understanding of the chemistry of wood strength. 

The theories presented are unproven. They are offered as a starting point—a point to be verified, refined, and reconsidered, a point from which, through mutual cooperation between the fields of engineering and chemistry, the chemistry of wood strength may be truly explained. 

Winandy, J.E. and Rowell, R.M. (1984) The chemistry of wood strength. Chapter 5, in The Chemistry of Solid Wood (ed. R.M. Rowell), American Chemical Society, Washington, DC, p. 218. 

Over the years the strength of wood has been, for the most part, studied by physical chemists and engineers and the chemistry of wood has been studied by organic chemists and biochemists. In a materials science approach to wood research, these disciplines must work together to relate the physical properties to the chemistry of the wood material. 

The macroscopic level of consideration takes into account fiber length and differences in cell growth such as earlywood, latewood, reaction wood, sapwood, heartwood, mineral content, resin content, etc. Difierences in growth chemistry can cause significant differences in the strength of wood. 

Molecular. At the molecular level the relationship of strength and chemical composition deals with the individual polymeric components that make up the cell wall. The physical and chemical properties of cellulose, hemicelluloses, and lignin play a major role in the chemistry of strength. However, our perceptions of wood polymeric properties are based on isolated polymers that have been removed from the wood system and, therefore, possibly altered. The individual polymeric components may be far more closely associated with one another than has heretofore been believed. 

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