7 - Furan Resins

Abstract

Furan resins are condensation products of furfuryl alcohol (FA). The resins are derived from vegetable cellulose, a renewable resource. One of the major advantages in furan resins stems from the fact that they are derived from vegetable cellulose. Suitable sources of vegetable cellulose are corn cobs, sugar cane bagasse, oat hulls, paper mill byproducts, biomass refinery eluents, cottonseed hulls, rice hulls, and food stuffs such as saccharides and starch. Furan-based monomers can polymerize through two well-known mechanisms. The first involves chain or polyaddition polymerization, which is initiated by free radical, cationic, or anionic promoters. Polymerization produces macromolecules with furan rings pendant on the main chain. The second method is polycondensation, also referred to as polymerization condensation. Aramid fibers are used as a reinforcing material for a phenol resin and a furan resin. The most important industrial furan resins are based on 2-furfuryl alcohol. Materials known to be suitable for curing furan resins include inorganic and organic acids. Examples of suitable organic and inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, tartaric acid, and maleic acid. Furan resins are used mainly in the foundry industry as sand binders for casting molds and cores. Furan resins are often used in combination with other resins. Furan resins are highly corrosion resistant; therefore, they are use in mortars and in cements. Improved mechanical properties are implemented by reinforcing with glass fibers.