Wood, Modified

wood that has been processed by some chemical substance (synthetic resin, ammonia, and so on) to improve its mechanical properties and impart water resistance to it. In most cases the wood is impregnated under pressure; polymerization or polycondensation of the chemical substances introduced into the wood (mers, oligomers, and others) is brought about by heat treatment or by irradiation with X rays and alpha, beta, and gamma rays in the presence of catalysts. Modified wood has 75 percent greater resistance to static bending than natural wood; it absorbs 3-5 times less water and is less susceptible to abrasive wear by a factor of 1.5-2.0. Modified wood is used to manufacture sliding bearings in units of farm machinery, parts that operate in aggressive mediums, and casting patterns and master forms.