Wooden rubber

The long, soluble polysaccharides that make up the hemicellulose portion of native hardwood and softwood species are called wood gum . The wood consists of 22 to 35 percent hemicellulose, a good 40 percent wood cellulose and, depending on the type of wood, up to 30 percent lignin and the living tissue, the so-called cambium layer .

To extract cellulose from wood, accompanying substances, including lignin , are removed by treatment with hydrogen sulfites . The hemicelluloses are also dissolved out by boiling with aqueous sodium hydroxide solution . The term wood rubber , which is now rarely used , was chosen for the substance obtained in this way. Essentially, wood gum is a polysaccharide mixture consisting mainly of xylans and a few mannans , arabans and galactans .