Chemistry of Wood Strength

Authored by: Jerrold E. Winandy , Roger M. Rowell

Handbook of Wood Chemistry and Wood Composites

Print publication date:  September  2012
Online publication date:  September  2012

Print ISBN: 9781439853801
eBook ISBN: 9781439853818
Adobe ISBN:


 Download Chapter



The source of strength in solid wood and engineered wood composites is the wood fiber. Wood is basically a series of tubular fibers or cells cemented together. Each fiber wall is composed of various quantities of three polymers: cellulose, hemicelluloses, and lignin. Cellulose is the strongest polymer in wood and, thus, is highly responsible for strength in the wood fiber because of its high degree of polymerization and linear orientation. The hemicelluloses act as part of a matrix for the cellulose and increase the packing density of the cell wall; hemicelluloses and lignin are also closely associated and make up the cell wall matrix in which the cellulose is imbedded. The actual role of hemicelluloses relative to the strength of virgin wood has recently been shown to be far more critical toward the overall engineering performance of wood than had previously been assumed. It is now accepted that one important role of hemicelluloses is to act as highly specific coupling agents capable of associating both with the more random areas (i.e., noncrystalline) of hydrophilic cellulose and the more amorphous hydrophobic lignin. Lignin not only holds wood fibers themselves together, but also helps bind carbohydrate molecules together within the cell wall of the wood fiber. The chemical components of wood that are responsible for mechanical properties can be viewed from three levels: macroscopic (cellular), microscopic (cell wall), and nano-molecular (polymeric) (Winandy and Rowell, 1984). Mechanical properties change with changes in the thermal, chemical, and/or biochemical environment. Changes in temperature, pressure, moisture, pH, chemical adsorption from the environment, UV radiation, fire, or biological degradation can have significant effects on the strength of wood.

Search for more...
Back to top

Use of cookies on this website

We are using cookies to provide statistics that help us give you the best experience of our site. You can find out more in our Privacy Policy. By continuing to use the site you are agreeing to our use of cookies.