Furfuryl alcohol resins

Furfuryl alcohol is comparable to kerosene or No. 1 fuel oil in flammabiUty, the Tag Closed Cup flash point is 170°F. In the presence of concentrated mineral acids or strong organic acids, furfuryl alcohol reacts with explosive violence. Therefore, precautions should be taken to avoid contact of such materials with the alcohol. Caution is also recommended to avoid over-catalysis in the manufacture of furfuryl alcohol resins. 

Uses. Furfuryl alcohol is widely used as a monomer in manufacturing furfuryl alcohol resins, and as a reactive solvent in a variety of synthetic resins and appHcations. Resins derived from furfuryl alcohol are the most important appHcation for furfuryl alcohol in both utihty and volume. The final cross-linked products display outstanding chemical, thermal, and mechanical properties. They are also heat-stable and remarkably resistant to acids, alkaUes, and solvents. Many commercial resins of various compositions and properties have been prepared by polymerization of furfuryl alcohol and other co-reactants such as furfural, formaldehyde, glyoxal, resorcinol, phenoHc compounds and urea. In 1992, domestic furfuryl alcohol consumption was estimated at 47 million pounds (38). 

The industrial value of furfuryl alcohol is a consequence of its low viscosity, high reactivity, and the outstanding chemical, mechanical, and thermal properties of its polymers, corrosion resistance, nonburning, low smoke emission, and exceUent char formation. The reactivity profile of furfuryl alcohol and resins is such that final curing can take place at ambient temperature with strong acids or at elevated temperature with latent acids. Major markets for furfuryl alcohol resins include the production of cores and molds for casting metals, corrosion-resistant fiber-reinforced plastics (FRPs), binders for refractories and corrosion-resistant cements and mortars. 

PhenoHc and furfuryl alcohol resins have a high char strength and penetrate into the fibrous core of the fiber stmcture. The phenoHc resins are low viscosity resoles some have been neutralized and have the salt removed. An autoclave is used to apply the vacuum and pressure required for good impregnation and sufficient heat for a resin cure, eg, at 180°C. The slow pyrolysis of the part foUows temperatures of 730—1000°C are recommended for the best properties. On occasion, temperatures up to 1260°C are used and constant weight is possible even up to 2760°C (93). 

Metal-casting cores/molds, furfuryl alcohol resins in, 12 272-273 Metal catalysis, dye degradation by, 9 381-384... 

It has been known for some time that lithium can be intercalated between the carbon layers in graphite by chemical reaction at a high temperature. Mori et al. (1989) have reported that lithium can be electrochemically intercalated into carbon formed by thermal decomposition to form LiCg. Sony has used the carbon from the thermal decomposition of polymers such as furfuryl alcohol resin. In Fig. 11.23, the discharge curve for a cylindrical cell with the dimensions (f) 20 mm x 50 mm is shown, where the current is 0.2 A. The energy density for a cutoff voltage of 3.7 V is 219 W h 1 which is about two times higher than that of Ni-Cd cells. The capacity loss with cycle number is only 30% after 1200 cycles. This is not a lithium battery in the spirit of those described in Section 11.2. 

Uses. Solvent for cellulose ethers, esters, resins, and dyes liquid propellant binder in foundry cores manufacture of resins including furfuryl alcohol resin (furan resin) and furfuryl alcohol-formaldehyde resins... 

Fig. 47. 15 MHz 13C MAS NMR spectrum of cured furfuryl alcohol resin a. The spectrum of the same resin obtained with dipolar dephasing (100 ps interrupted decoupling) b (reprinted from Ref.2341 with permission)...

Drastic alkali resistance tests consisting of heating wood specimens in boiling 10% NaOH for 16 days reduced the crushing strength at the elastic limit for untreated southern yellow pine from 620 to 80 psi and for the wood containing 71% furfuryl alcohol resin from 2650 to 890 psi (56). 

Dimensional Stabilization of Wood with Furfuryl Alcohol Resin... 

Table I. Efficiency of Furfuryl Alcohol Resin Treatment of End Matched Yellow Poplar Sticks...

Table II. Efficiency of Furfuryl Alcohol Resin Treatment of Douglas fir and Engelmann Spruce cross Sections Cured at 120°C in Aluminum Foil, the Antishrink Efficiency CASE) and the Relative Abrasion Resistance.

Figure 2. Relative toughness vs. logarithm of the zinc chloride catalyst concentration for end-matched furfuryl alcohol resin treated yellow poplar sticks. O, average relative toughness of resin-treated specimens. A, average relative toughness of specimens impregnated with the same aqueous catalyst concentration and subjected to the same heating and time cycle with no furfuryl alcohol present. Arrows indicate range of relative toughness values for the resin-treated specimens.

Figure 3. Relative abrasion resistance vs. logarithm of the zinc chloride catalyst concentration for end-matched cross sections of furfuryl alcohol resin-treated Engelmann spruce. Arrows indicate range of relative abrasion resistance values.

Table III Effect of furfuryl alcohol resin treatment of wood on the weight loss due to decay under ASTM soil-block tests for 12 weeks. 1/...

A limited amount of experimentation was made with plywood and laminated panels. These experiments used the same ammonium lignosulfonate/poly(furfuryl alcohol) resin or monomer systems, with H2O2 activation, maleic acid as catalyst, and Douglas-fir veneer. A dry wood failure of 100% was obtained with plywood (83% and 95% wet, after vacuum-pressure soak), with dry shear strength of 1135 psi for parallel laminated panel made with ammonium lignosulfonate-furfuryl alcohol (525 psi wet), and of 1640 psi for the one made using ammonium lignosulfonate/furfuryl alcohol resin (650 psi wet). 

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