Furan polymer concrete

Furan polymers are based on furfuryl alcohol, which is derived from agricultural residues such as corncobs, rice hulls, oat hulls, or sugar cane bagasse. The furan prepolymer is usually cross-linked with furfuryl alcohol, furfuraldehyde, or formaldehyde to yield thermosetting polymers, highly resistant to most aqueous acidic or basic solutions and strong solvents such as ketones, aromatics, and chlorinated compounds. The important characteristic of furan resins is their ability to be stored for long periods of time (up to 5 years), even at low temperatures. 

However, short-term pot life and toxicity in the uncured state hamper the use of these resins, and high self-heating temperature causes significant thermal stresses, which adversely affect the strength characteristics of furan PC. It was found that the 

The furan polymers are used as binders in mortars and grouts to achieve chemically resistant brick floors (e.g., carbon brick and red shale brick) and linings. In addition to exhibiting superior chemical resistance, these floors have excellent resistance to elevated temperatures and extreme thermal shock [2,6,7], 

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Furan polymer concrete is a corrosion-resistant polymer material. Endurance tests (a year or more) showed high resistance of this material to most industrial chemicals, except oxidants (nitric acid, acetic acid) and some solvents (acetone, benzene, alcohol). 

Furan mortars and grouts are formulated using either 100% carbon or part carbon/silica fillers. Although not normally used as a monolithic surfacing, they are used to produce furan polymer concrete. Either formulation is satisfactory to resist normal atmospheric pollution but more aggressive pollutants might require the use of 100% carbon filler. Furan grouts normally are filled with only 100% carbon filler. 

TABLE 3.6 FURAN POLYMER CONCRETE-QUAKER OATS CHEMICALS... 

Furan polymer concrete is a strong, concrete-type material with outstanding corrosion resistance made by bonding size-graded aggregates with a furfuryl alcohol-based furan" resin. 

Corrosion tests have been conducted on 1 inch x 2 inch furan polymer concrete test cylinders made with Quaker s QO FA-RoK resin/catalyst system by totally immersing them in several key media at 1 SOT for one year. Results of these tests indicate that furan polymer concrete should be suitable for use in environments that have been serviced for many years by furan mortars and furan FRP equipment. 

Furan polymer concrete is attacked by strong oxidizing agents, a few aggressive solvents and chemicals that attack silica. However, it may perform satisfactorily with some of these media where the service is a splash/spill wash down exposure or where materials such as very dilute sodium hypochlorite are used as cleaning agents. 

The polymer concretes are distinguished by the nature of the binder e.g., furan, polyester, epoxy, phenol formaldehyde, carbamide, and so on. The classification of the main types of polymer concrete according to the kind of synthetic resins involved is shown in Figure 1.2 [7],... 

Polymer concretes based on phenol-formaldehyde, acetone-formaldehyde resins and monomers, and methyl methacrylate are much less common. Phenolic resins are similar to furan in many physical and mechanical properties. However, they are unstable in alkalis like polyester resins [7],... 

Binders used for polymer concrete include epoxy resins (EP), unsaturated polymer resin (UP), vinyl ester resin (VE), methyl metacrylate (MMA) and furan resins [9-11]. 

Most synthetic resins are petrochemical-based. Furan resins are unique in that they are agriculturally based, with the furfurayl alochol produced from agricultural byproducts such as com cobs, bagasse, rice, and oat hulls. Although the most versatile of all resins in use, furan resins are not a popular choice for use as polymer concrete because of their tendency to shrink and their brittleness. They do provide a wide range of corrosion resistance and are resistant to atmospheric corrosion (see Table 10.2). 

Phenolic resins are not used in monolithic surfacings in grouts or in polymer concretes but are extensively used in mortars. They are two-component systems as are the furan resins using 100% carbon filler, or 100% silica filler, or part carbon and part silica filler. Like the epoxies, the phenolic resins can be allergenic to sensitive skin. Protective clothing should be worn by persons handling the phenolic resins. Phenolic resins have a limited shelf life and must be stored at 45°F (7 C). 

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