There are many factors that cause wood discoloration, mainly divided into two aspects: internal factors and external factors:
1、 Internal factors causing wood discoloration:
Wood is mainly composed of cellulose, hemicellulose, lignin and a small amount of extract. Complex natural polymer compounds contain not only unsaturated double bond and conjugation system of carboxyl group, but also hydroxyl group.
II. The external factors that cause wood discoloration are:
Wood is very easy to be affected by the external environment, which makes the surface texture of wood loose, rough, discolored and faded, and even the wood loses the fiber attached to the surface, and is gradually dropped by cracks or brittle fragments.
3、 The causes and influencing factors of wood discoloration and how to prevent and eliminate them
Photochromism: some materials in wood choose to absorb light with wavelength greater than 290nm, which leads to the change of electron between energy levels and the formation of photochromic chemical bond, which leads to the change of wood color.
Photochromic protection: block ultraviolet rays; change the structure of light absorbing components in materials, destroy the structure of color changing materials, so as to isolate oxygen and capture atomic oxygen, capture free radical extraction solvent.
In order to eliminate light color and restore the original normal color of wood surface, the following two methods can be used:
1. Remove with sandpaper or planer. Suitable dyes or pigments can be used for color changing materials.
2. wood was treated with oxidant bleach such as hydrogen peroxide and sodium chlorite.