Furane resin

Furane resins are superior to polyesters and epoxies for resistance to ketones, chlorinated solvents and carbon disulfide. However, as they are 

Dimensional Stability Stiffness Hardness Electrical Conductivity Thermal Conductivity Moisture Resistance Handleability 

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The inherent fire resistance and low smoke properties of furan resins appear to be related to the high degree of charring that takes place with minimum evolution of volatiles when exposed to fire. 

A number of cement materials are used with brick. Standard are phenolic and furan resins, polyesters, sulfur, silicate, and epoxy-based materials. Carbon-filled polyesters and furanes are good against nonoxidizing acids, salts, and solvents. Silica-filled resins should not be used against hydrofluoric or fluosihcic acids. Sulfur-based cements are limited to 93°C (200°F), while resins can be used to about 180°C (350°F). The sodium silicate-based cements are good against acids to 400°C (750°F). 

There are now commercially available a large range of laminated plastics materials. Resins used include the phenolics, the aminoplastics, polyesters, epoxies, silicones and the furane resins, whilst reinforcements may be of paper, cotton fibre, other organic fibres, asbestos, carbon fibre or glass fibre. Of these the phenolics were the first to achieve commercial significance and they are still of considerable importance. 

Because of their favourable price, polyesters are preferred to epoxide and furane resins for general purpose laminates and account for at least 95% of the low-pressure laminates produced. The epoxide resins find specialised uses for chemical, electrical and heat-resistant applications and for optimum mechanical properties. The furane resins have a limited use in chemical plant. The use of high-pressure laminates from phenolic, aminoplastic and silicone resins is discussed elsewhere in this book. 

The furan or furane resins mainly find use because of their excellent chemical and heat resistance. In the past they have mainly been used in applications peripheral to the plastics industry such as foundry resins, for chemically resistant cements and for binders. Recent developments have facilitated their use in laminates for chemical plant. 

The two intermediates of commercial furan resins are furfural and furfuryl alcohol. Furfural occurs in the free state in many plants but is obtained commercially by degradation of hemicellulose constituents present in these plants. There are a number of cheap sources of furfural, and theoretical yields of over 20% (on a dry basis) may be obtained from both com cobs and oat husks. In practice yields of slightly more than half these theoretical figures may be obtained. In the USA furfural is produced in large quantities by digestion of com cobs with steam and sulphuric acid. The furfural is removed by steam distillation. 

Catalytic hydrogenation of furfural in the presence of copper chromite leads to furfuryl alcohol, the major intermediate of the furan resins Figure 28.1). 

For commercial use a partially condensed furan resin is normally prepared which is in the form of a dark free-flowing liquid. Final cure is carried out in situ. 

The principal applications for furan resins are in chemical plant. Specific uses include the lining of tanks and vats and piping and for alkali-resistant tile cements. The property of moisture resistance is used when paper honeycomb structures are treated with furan resins and subsequently retain a good compression strength even after exposure to damp conditions. 

Furane resin-chopped strand mat laminates have tensile strengths in excess of 200001bf/in (140 MPa), a heat distortion temperature of about 218°C and good fire resistance. 

GANDiNi, A. furan resins , Encyclopedia of Polymer Science and Technology (2nd Edition), Vol. 7, pp. 454-73, John Wiley, New York (1987)... 

Biomass phenolic and furan resins polyimides glassy carbons, binder and matrix carbons" graphite films and monoliths activated carbons ... 

Resins not softened by heating are the phenolics furan resins, aminoplastics, alkyds, allyis, epoxy resins, polyurethanes, some polyesters, and silicones. 

Epoxide and furan resins These materials, somewhat more expensive than the polyesters, may also be fabricated without the use of pressure, and at... 

One of the most important furan resins from an industrial standpoint is undoubtedly that obtained from 2-furfuryl alcohol. The final cross-linked product displays outstanding chemical, thermal and mechanical properties8. ... 

In contrast with the above situation, the polymerization of 2-furfurylidene methyl ketone, di-2-fiirfurylidene ketone and their homologues has been the subject of a large volume of (mainly technical) publications because of the useful applications of the final cross-linked products. As pointed out in the introduction, this review does not deal with the technological aspects of furan resins and in this section only the mechanistic aspects of the first phase of these polymerizations will be discussed. 

Euran Furan resins are thermosetting polymers derived from furfuryl alcohol and Furfural. The cure must be carefully controlled to avoid the formation of blisters and delaminations. To obtain optimum strength and corrosion resistance, furan composites must undergo a postcure schedule at carefully selected temperatures depending upon the laminate thickness. Equipment made with furan resins exhibits excellent resistance to solvents and combinations of acids and solvents. These resins are not for use in strong oxidizing environments. 

No discussion of polymer fire retardance would be complete without at least a brief mention of the highly aromatic polymers, all of which are very difficultly flammable if they burn at all (1 ). Although the low flammability of phenolic and furane resins are well known, these thermally... 

Morrill Act of 1862, 24 353 Mortality studies, PCB-related, 13 141 Mortar cements, 5 500t Mortars, 5 467, 500t 21 482-483 citric acid application, 6 648 furan resins in, 12 274 slaked lime in, 15 64 Mortar substitute, sulfur coatings as, 23 593... 

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