Resin impregnated wood

Table I. Average Lifetime of Resin-Impregnated Wood in Ground Contact...

Use First stage of urea formaldehyde resins impregnating wood to increase hardness and fire resistance and to form self-binding laminations for plywood manufacture permanent-press fabrics. 

Boron has been included as a neutron absorber in various materials in addition to concrete. For example, borated graphite, a mixture of elemental boron and graphite, has been used in fast-reactor shields. Boral, consisting of boron carbide (B4C) and aluminum, and epoxy resins and resin-impregnated wood laminates incorporating boron have been used for local shielding purposes. Boron has also been added to steel for shield structures to reduce secondary gamma-ray production. In special situations, where a shield has consisted of a heavy metal and water, it has been beneficial to add a soluble boron compound to the water. 

Resistance to chemical attack is generally improved by resin impregnation, which protects the underlying wood and reduces movement of Hquid into the wood. Resistance to acids can be obtained by impregnating with phenoHc resin and to alkaHes by impregnating with furfural resin (see Phenolic RESINs). 

As with so many research areas in wood modification, much of the early work in resin impregnation was performed by Alfred Stamm and co-workers at the Forest Products Laboratory in Madison (Stamm and Seborg, 1941). On the basis of this work, two veneer-based prodncts were developed (Impreg and Compreg), which will be described in... 

Cellulose, which is more fibrous than wood flour, is used as a filler for urea and melamine plastics. Melamine dishware is a laminated structure consisting of molded resin-impregnated paper. Starch and soybean derivatives are biodegradable, and the rate of disintegration of resin composites containing these fillers may be controlled by the amount of these fillers present in polymers. 

The impregnation of PF (phenol-formaldehyde) resin into wood was studied in the early part of the twentieth century. PF resin wood composites have been commercialized as Impreg and Compreg for their high mechanical strength and dimensional stability. Although the enhancement of decay resistance by PF resin treatment was also found earlier [1], it has not been applied to wood preservation techniques for the prevention of biodeterioration. 

Acetylation and phenolic resin impregnation arc found to be applicable to reconstituted wood products in yielding good biological resistance. Treatments with crosslinking agents and WIC can be applied to these end products but further studies are required to improve production technology. 

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